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The Great Connexion: Hume's Metaphysical Logic Of Belief-Constructed Causation


Vance Maxwell


I. Introduction

       It is a commonplace that Hume the philosopher[1] is essentially Hume the sceptic. Hume deploys his skeptical arguments in both epistemology and ethics.

       In the epistemological context, Hume argues that we can have no rational knowledge of matters of fact, reason in its strict or a priori sense yielding intuitive or demonstrative knowledge only of relations among ideas. Rather, our knowledge of matters of fact involves our applying a psychologically constituted relation of causal necessity to empirical elements. And while these elements, impressions and ideas[2], manifest relations of contiguity, succession and repetition, they do not reveal that crucial relation of power or necessary connection essential to causal inference, and to its mental source and form, 'belief'. Accordingly, the relation of power or necessary connection is somehow formed and felt by the mind, and applied adventitiously to experience hence articulated as cause-to-effect or effect-from-cause, as the idea of 'effect', or 'cause', is inferred from a 'present impression' of the other, respectively. As Hegel puts it, "Necessity is thus not justified by experience, but we carry it into experience; it is accidentally arrived at by us and is subjective merely."[3] While we regard the empirical causal relation as necessary, whether of 'outer sense' and physical or of 'inner sense' and mental, its 'necessity' is not intrinsic, but psychological and customary or habitual: we can never perceive either bodies or minds to act from an inherent power binding them to their effects in an absolute tie. Hence, from the side of the empirically given, Hume says, any 'cause' can produce any 'effect' and any 'effect' can proceed from any 'cause'. In this way, all empirical or causal judgments are synthetic (e.g., 'fire burns wood') and can be denied without contradiction. And accordingly, this constructed causal necessity is itself contingent as empirically applied to the atomistic sequences of impressions and their ideas.

       In the ethical context, Hume again argues that reason, restricted a priori to relations among ideas and empirically to relations among matters of fact, cannot either motivate ethical conduct or yield moral judgment. Only feelings of approbation or disapproval, deriving from a universal sympathy, can move us to act; and these feelings themselves, taken as focussed on matters of fact, constitute our moral judgments. Reason is both passive and merely auxiliary in moral life: it can identify situations calling for ethical response, and yield causal knowledge. But reason cannot yield knowledge of the moral 'ought', 'right' or 'wrong'. These, with causal necessity, are felt or believed.

       Hume completes his scepticism with this rejection of both material and spiritual substance, taken as objective and subjective substrata respectively grounding 'outer' and 'inner' sense. Proof here would be empirical; and no sense impressions of substrata exist to give meaning to ideas of such substances. But we do have sense impressions of collections of impressions of 'outer' and 'inner' sense. And so, in each case, the idea of substance is only the idea of a collection or 'bundle' of sense impressions. Notwithstanding, we believe in the existence of objective continuants or bodies, and of subjective continuants or minds/persons.

       What, then, is the dynamic of Humean scepticism? It is surely the opposition generated as Hume argues that, against reason, we stubbornly believe that constructed causality is independently real, that moral judgment and conduct are objective, and that bodies and mind/persons are real entities in themselves. Hume thinks this opposition to be both incomprehensible and beyond remedy, although irrationally we do and must believe as he explains. Hume the philosopher is baffled by this opposition; but Hume the man accepts it.[4] In this way, Hume distinguishes and separates the theoretical life of the philosopher from the practical life of the man of affairs: "Be a philosopher; but, amidst all your philosophy, be still a man".

       Our question now is this: can Hume the philosopher be reduced to Hume the sceptic, the psychological epistemologist, whose accounts of causality and belief seem utterly mentalistic, and to relate these philosophical categories only contingently to something 'objective' or otherwise real? The answer is surely no: it would be strange if Hume, a great philosopher and the greatest of the classical empiricists, could not provide resources at least to enlarge the context in which we might place, understand and even assess his scepticism. For, as will be argued here, it cannot stand alone, or indeed prevail.

       We must invoke Hume the metaphysician, but not dogmatically to impose metaphysics on the archetypal 'anti-metaphysician' as so many, like A.J. Ayer[5], treat him. Rather, Hume thinks himself a metaphysician who "must cultivate true metaphysics with some care, in order to destroy the false and adulterate".[6] Thus, while, Hume rejects the transcendentalism of Plato, and the rationalism of Spinoza, he imparts an unfailing sense of the universal as borne by his principle Custom. But more directly and concretely, Hume regards his enquiries into necessary connection or causality as metaphysical: "There are no ideas which occur in metaphysics more obscure and uncertain, than those of power, force, energy, or necessary connection of which it is at every moment necessary for us to treat in all our disquisitions. We shall, therefore, endeavour, ... to fix, if possible, the precise meaning of these terms, and thereby remove some part of that obscurity which is so much complained of in this species of philosophy" (EU 61-2). Now, if Hume's constructionist or belief doctrine of causality does, or is intended to remove some of the "obscurity" of these ideas, obscurity yet remains. However, while he does not or cannot elaborate, Hume does give that obscurity an import and distinctive metaphysical structure, to which even the best of current scholarship is oblivious. Moreover, a certain causal, and hence metaphysical, precision here can be drawn from a careful reading of Hume's texts, that precision being intended by Hume, as the above excerpt from EU clearly shows.

       We mean this: it is a mistake, made commonly by philosophers and scholars, to think that causality in Hume reduces at once to belief or constructed causality alone. Ayer conspicuously thinks this, for example.[7] And we shall see that Hume himself misleadingly promotes this reduction. However, as we argue in Parts III and IV of this paper, we find in Hume at least two kinds and levels of causality that stand as conditions for the possibility of his doctrine of causality as constructed from belief. These we may call original causality -- 'impression-to-idea' -- and aboriginal causality -- 'Custom' or 'Nature' -- such that Custom/Nature grounds impression-to-idea which in turn grounds belief-constructed causality[8]. Metaphysically, then, we have the cause (aboriginal) of a cause (original) of a cause (belief-constructed). Now, as in Hegel's words we "carry it [belief-causality] into experience", the meeting of the subjectively constructed causality or necessity with the atomic sequences of impressions ('outer' and 'inner') and their ideas (which empirical sequences as such can manifest no inherently necessary connection) is alone the focus of causal contingency, synthetic causal propositions, and thus of Hume's scepticism. But, we shall argue, no contingency or scepticism infects either original causality (impression-to-idea) or aboriginal causality, the metaphysical ground of original and of constructed causality. Hence, while contingency in Hume has a certain nature and scope, it is also contained and limited by the metaphysical necessity of original and of aboriginal causality, which indeed it presupposes.


II. The Nature, Scope And Limits Of Contingency

       This paper will place great weight on original causality as manifested in the impression-to-idea relation. The reader will have noted that, in making our preliminary claim of three levels of causation in Hume, we place original causality between aboriginal and belief-constructed causation. Evidently, then, original causation mediates the determination by Custom of the great plurality of beliefs, 'customs' or 'habits' informing what Livingston emphasizes as our 'common life'. As Hume, in the opening section (Pt. I) of Book I of the Treatise moves to establish the causality of impression-to-idea, he claims that their "constant conjunction, in such an infinite number of instances, can never arise from chance; but clearly proves a dependence of the impressions on the ideas, or of the ideas on the impressions" (T4-5). In view of our denying above that contingency and scepticism apply to either original or aboriginal causation, it now behooves us to determine briefly the nature and scope of contingency as functions of belief-constructed causation.

       In his Treatise, Hume identifies contingency with chance, and defines chance as "nothing real in itself ... merely the negation of a cause" (T125). But in his Enquiry, he writes: "Though there be no such thing as chance in the world, our ignorance of the real cause of any event has the same influence on the understanding and begets a like species of belief or opinion" (EU 56). Chance, then, involves the apparent negation of a cause where, nevertheless, the mind is determined to believe in, or to expect, equal outcomes. Hume accordingly discusses both chance and causality within probability or the quantifying and proportioning of belief in respect of two or more possible outcomes. Thus, whether the mind is determined by the apparent negation of a cause (chance), or by constructed causes, it is determined to believe in outcomes probabilistically. Since belief involves the feeling of power or necessary connection involved in the constructionist ascription of causality to experience, it is evident that, for Hume, contingency or chance is not ultimate, but is enclosed within belief itself. Contingency is hence subject to the conditions of belief given by original and aboriginal causality as proposed in Part I. We shall pursue them in Parts III and IV.

       For Hume, probability involves a mix of chance and of causality: in chance, the mind is determined to believe indifferently in equally possible outcomes; in causality, the mind is determined to believe in terms of relative frequency of actual causes. Let us elaborate, using Hume's example of throwing a die.

       The die has six sides; we assume that the die is not loaded, and that four sides have identical dots or patterns. Now the mind is determined by chance to believe indifferently that each of the sides has, as such, an equal chance with each of the others of turning up. The indifference of the belief, which here is sum of six beliefs, lies in the negation, in each case, of a cause (or loading) which added to the side, would make it turn up, and destroy the indifference of the chance belief. But note that the chance belief occurs within the causal beliefs that: (i) The die is thrown or caused to fall by its gravity, solidity, etc.; (ii) the die falls in a form of trajectory; (iii) the die falls so as to turn up one side. Hence, the contingent belief that any side can turn up is made possible and bounded by the causal belief that one side must turn up in the throw.

       Of course, other factors enter to qualify the contingent belief in terms of probability. From the standpoint of the sides of the die taken only as sides, no probability can arise. Hence, the belief in pure chance is the sum of six equal beliefs, each 'negating' a (loading) cause. But when we consider the sides in terms of an identical pattern on four sides, and another identical pattern on two, the causal principle which previously directed us to all six sides with equal force, each side yielding one-sixth of the total, now directs us to pit two force-sums, 4/6 (1/6+1/6+1/6+1/6) and 2/6 (1/6+1/6), against each other: the inferior belief destroys the superior belief by half its force. In this way the summed belief in pure chance divides and proportions into the probabilistic belief that, 2:1, a side bearing the prevailing pattern will turn up. As Hume says, we cannot know which side will turn up; but we do know that a side bearing the prevailing pattern is twice as likely to turn up as is another side of the die.

       What, then, is the scope of contingency or chance? Since Hume first defines chance as the "negation" of a cause and later, denying chance, clarifies "negation" as "ignorance" of a cause, contingency appears where we do not and cannot perceive a cause or necessary connection.[9] Two domains are involved here: first, we have the domains of sense impressions (outer and inner) in atomic sequences (spatial/temporal for outer, temporal for inner sense) thus excluding inherent causal necessity. Second, we have the domains of ideas which exactly copy their original impressions of outer and inner sense, except for having a lesser force, and hence also arise in a temporally atomistic sequence likewise excluding inherent causality or necessary connection. But contingency, for Hume, does not and cannot arise in the domains of original and aboriginal causality per se or as themselves causally related, these denials being argued in Parts III and IV of this paper. Rather, contingency or chance appears to confront only belief or constructionist causality as carried into the domains of atomistic experience, outer and inner. Finally, here note this: when Hume denies the reality of chance, and clarifies 'negation' as 'ignorance' of a cause, he has to mean that a cause, though unperceived, does exist. In claiming this, he violates and exceeds metaphysically his otherwise relentless and rigorous application of Berkeley's thesis that 'to be is to be perceived'. For he now clearly implies that a causal or necessary connection, though not perceived in the atomistic domains of sense impressions and their corresponding ideas, exists and is nonetheless somehow present. This connection Hume ultimately invokes as a 'pre-established harmony':

Here, then, is a kind of pre-established harmony between the course of nature and the succession of our ideas; and though the powers and forces by which the former is governed, be wholly unknown to us; yet our thoughts and conceptions have still, we find, gone on in the same train with the other works of nature. Custom is that principle, by which this correspondence has been effected; so necessary to the subsistence of our species; and the regulation of our conduct, in every circumstance and occurrence of human life.[10]

In this passage, Hume (i) states a direct relation between his ultimate principle, Custom, and the entire human fabric of belief and action, including morality as "the regulation of our conduct"; (ii) states this relation causally, such that Custom is, for the human intellect, the ultimate cause "by which this correspondence has been effected".

       Hume also invokes "powers and forces", which though "wholly unknown to us", nevertheless govern "the course of nature" such that "our thoughts and conceptions [go] on in the same train with the other works of nature". These powers are those of bodies affecting bodies and minds (as when we, looking, involuntarily perceive fire to burn wood), and of minds affecting bodies (as when we will to move a limb) and minds (as when we will to calculate, or to convince another mind). These are the physical and mental domains where activity is expressed in synthetic propositions, and where Hume lays bare what Russell calls the "tragic" problem of induction. In short, these are the domains into which we carry belief-constructed causality, the ultimate cause of which is, for man, Custom. As noted above, however, we shall argue that original causality (impression-to-idea) mediates the ultimate metaphysical action of Custom in generating the entire fabric of belief-constructed causation. In so arguing, we hope to shed light on the metaphysical relation of Custom to beliefs (e.g., that wood augments flame), and hence to illumine somewhat the "secret powers" which Hume repeatedly attributes to bodies and minds even though these powers be "wholly unknown to us".

       Now, before we go on to investigate belief-constructed causality in Part III, we should ask why scholars typically reduce all causality in Hume to belief. We have seen Ayer, writing relatively late, doing just this (n.7). Gasking, writing earlier[11], generally discusses what Hume would understand as synthetic causal beliefs when he considers "some typical statements of causal connection - 'The train-crash was due to a buckled rail; 'Vitamin B deficiency causes beri-beri'..." Gasking does not struggle with impression-to-idea or Custom at all in his paper. McNabb, writing the Hume article in The Encyclopedia of Philosophy, tells us: "Hume found that all inferences from the existence of one object to that of another are non-demonstrative and based on the relations of cause and effect. An exception to any causal connection is clearly imaginable; so is a pure fluke or a sudden change in the course of nature. Only by experience can we know whether any of these occur".[12] McNabb does consider impression - idea, but he mistakenly treats this distinctive relation as non-causal, as we show in Part IV. Several articles on Hume's two definitions of 'cause' (to be noted shortly) thereby restrict themselves to belief (or sceptical) causality.[13] We need not multiply illustrations of this scholarly reduction of Humean causation to belief as a posteriori synthetic.

       To answer our question, at least in part, Hume himself is significantly responsible for his reduction by scholars to philosophical sceptic par excellence. He himself often writes as though all causality is not more than psychological association carried into resisting atomistic domains of outer and inner sense: the elements of these domains in their contiguity, succession and (especially) repetition, somehow externally cause that association as our belief in their (the elements') causal nature.

       For example, it is well known that Hume divides relations into two classes: "such as depend entirely on the ideas, which we compare together, and such as may be chang'd without any change in the ideas" (T69). These relations are a priori and empirical, respectively. In the first class, Hume places "resemblance, contrariety, degrees in quality and proportions in quantity or number" (T70). In the second class he places "identity, the situations in time and place, and causation" (T73). As Livingston says, "Relations of the first sort are internally connected to the relata: ... Relations of the second sort are externally connected to the relata: ..." The first are "[t]he only infallible relations" (T79), and are alone "objects of knowledge and certainty" (T70), thereby constituting "the foundation of science" (T73). And the second, in Livingston's words, are "contingent, and propositions describing them are vulnerable to empirical test."[14] Clearly, then, Hume here characterizes all causality as empirically contingent, such that all causal propositions are synthetic, confutable and hence merely hypothetical.

       Again, Hume's famous two definitions of 'cause', given in both Treatise and Enquiry, taken together, characterize causality as essentially belief-constructed. In the Treatise, Hume introduces these definitions: "There may two definitions be given of this relation, which are only different, by their presenting a different view of the same object, and making us consider it either as a philosophical or as a natural relation; either as a comparison of two ideas, or as an association betwixt them." Hence:

[1] We may define a cause to be 'An object precedent and contiguous to another and where all the objects resembling the former are plac'd in like relations of precedency and contiguity to those objects that resemble the latter.'

Hume continues: "If this definition be esteem'd defective, because drawn from objects foreign to the cause, we may substitute this other definition in its place viz":

[2] 'A CAUSE is an object precedent and contiguous to another, and so united with it, that the idea of the one determines the mind to form the idea of the other, and the impression of the one to form a more lively idea of the other.' (T169-70).[15]

We may say that Df. [1] presents the constant conjunction and succession of 'objects' (impressions and their ideas) necessary to generate the impression of a powerful 'cause' enlivening the idea of an 'effect', and thus producing belief in the relation as expressed in Df. [2].

       And, finally, we shall go to the Abstract of Hume's treatise for an excellent summary statement of this reductionist tendency in Hume:

Were a man, such as Adam, created in the full vigour of understanding, without experience, he would never be able to infer motion in the second [billiard] ball from the motion and impulse of the first. It is not anything that reason sees in the cause, which makes us infer the effect. Such an inference, were it possible, would amount to a demonstration as being founded merely on the comparison of ideas. But no inference from cause to effect amounts to a demonstration. Of which there is this evident proof. The mind can always conceive any effect to follow from any cause, and indeed any event to follow upon another; whatever we conceive is possible, at least in a metaphysical sense: but wherever a demonstration takes place, the contrary is impossible, and implies a contradiction. There is no demonstration, therefore, for any conjunction of cause and effect. And this is a principle, which is generally allowed by philosophers. (T(A)650-51)[16]

Now, by "experience" here Hume means what he always means: the atomic or divisible sequences of outer and inner impressions and their ideas, manifesting the external relations of contiguity, succession and constant conjunction, and generating that belief which articulates them as 'cause' and 'effect', and is itself adventitious.

       In concluding this Part, we note once again two sentences in the above text: (i) "But no influence from cause to effect amounts to a demonstration"; (ii) "There is no demonstration, therefore, for any conjunction of cause and effect". Now, these claims notwithstanding, we shall argue in Part IV that Hume's doctrine of original causality (impression-to-idea) "amounts to" just such a demonstration. And, since original causality functions crucially to generate belief as "revivified" idea, we shall consider it as so functioning, thus working back to impression-to-idea in itself, and then finally as grounded in Custom. Proceeding thus, we can see how belief-constructed causality, applied to 'contingent' phenomena and hence the focus of Hume's scepticism, is made possible and thus limited by original causality itself grounded in aboriginal causality, or Custom.


III. Belief-constructed Causality

       For Hume, constructed causality is psychological in that the mind's or 'soul's'[17] building of belief, the feeling of power or a necessary connection among phenomena, leads us to call one phenomenon (or impression of 'outer' or 'inner' sense) a 'cause' and another its 'effect'. In a careful analysis found mainly in the Treatise (Bk. I, Pt. III), but also in the Enquiry (Section VII), Hume arrives at four relations pertaining to apparently contingent phenomena or impressions and their ideas. These relations, taken together, supply the necessary and sufficient conditions generating that belief leading us to ascribe causality to the phenomena: (i) The impressions (e.g., 'fire' and 'burning wood') must be perceived as contiguous or close together; (ii) The impressions must be perceived in temporal succession; (iii) The impressions must be repeatedly perceived as both contiguous and in succession; (iv) The impressions must be perceived as necessarily connected. The three relations of contiguity, succession and repetition pertain to the atomic or discrete phenomena themselves; but, while necessary, they are not sufficient to generate our attributing designations of 'cause' and 'effect' to them. What alone adds sufficiency to these conditions, and enables - indeed, forces - us to ascribe causality to the impressions, is the feeling of power constituting the relation of necessary connection now applied to the phenomena: 'fire' (cause) - 'burning wood' (effect). That feeling of power is the relational feeling of necessary connection, and it occurs as belief, to which we now turn.

       Hume thinks himself the only philosopher in history to ask and to answer the question: What is belief? For Hume definition is the analysis of a whole into its parts: "Complex ideas may, perhaps, be well known by definition, which is nothing but an enumeration of those parts or simple ideas, that compose them" (EU 62). Thus we may understand belief to be a kind of whole, or complex idea, such that to define it is to exhibit its parts. We can say, then, that belief has four parts: (i) an impression; (ii) an idea; (iii) a causal relation between an impression and an idea; (iv) the revivifying of the idea as somehow the effect of the causal relation. Now, the mind must already possess the idea such that when an associated impression forces the mind to think the idea more strongly than was the case, the mind believes the idea in what a commentator calls a "reality feeling".[18] Hume illustrates with the idea of home: I have the idea of home; and when, nearing home, I actually see a landmark (have a present impression of sense), my idea of home is revivified such that I now believe home to be real and imminent. Or, seeing a match applied to wood, I find my mind forced to the idea of the wood's burning such that the idea is strengthened, and I thereby believe that the wood will burn.

       Hume is both careful and consistent in denying that the difference between our believing x and disbelieving y lies in our thinking x to exist, and y not to exist. In the Treatise (Bk. I, Pt. II: VI), Hume clearly anticipates Kant's denial that existence is a property or predicate. Holding that esse est percipi, he denies that any particular impression gives rise to the idea of existence. Hence,"that idea when conjoin'd with the idea of any object, makes no addition to it. Whatever we conceive, we conceive to be existent. Any idea we please to form is the idea of a being; and the idea of a being is any idea we please to form" (T66-67). Moreover, Hume argues that if our believing x were to add a property, we could never believe x, since x would thereby change and cease to be x: "When you wou'd any way vary the idea of a particular object, you can only encrease or diminish its force and vivacity. If you make any other change on it, it represents a different object or impression" (T96). Accordingly, he concludes that "... as belief does nothing but vary the manner, in which we conceive any object, it can only bestow on our ideas an additional force and vivacity" (T96). It follows that to believe x and to disbelieve y is to think them in a different manner, such that they remain x and y: "Nothing is more evident than that those ideas to which we assent, are most strong, firm and vivid, than the loose reveries of a castle builder" (T97). We add now, and emphasize, that belief always occurs in relation to a present impression, outer or inner, as the belief involved concerns, for example, fire burning wood or one's willing to cross the room. Thus belief, whatever it fully is, expresses a kind of inference from what is present to what is absent, from a present impression (fire) to the revivified idea of what is absent, but hence believed (burning wood).[19] And, of course, the inference moves from a present cause to an absent but expected effect, or from a present effect to an absent but remembered cause, temporal succession and precedence being elements in belief as a defined whole.

       To continue, Humean belief is a construction leading us to ascribe causality to experience or phenomena in these way: (i) The mind repeatedly experiences the contiguity and succession of phenomena ('fire'-'burning wood') moving repeatedly from impression (fire) to impression (burning wood), and then from impression (fire) to idea - note the change - (burning wood) as an association of increasing force, increasingly revivifying the idea. (ii) From repeated associations, in which the mind moves with increasing force from impression to idea, there arises an original impression of power or necessary connection; this arises subjectively, since mere repetition of contiguity in experience cannot generate an original impression. (iii) From that original impression of power or necessary connexion there arises, as its 'copy', the idea of power or necessary connection which is then carried into outer and inner phenomena or experience as the 'cause-effect' relation.

       It is now appropriate to let Hume speak for himself on belief causation, and thus we quote a crucial summation from the Enquiry:

It appears, then, that this idea of a necessary connexion among events arises from a number of similar instances, which occur, of the constant conjunction of these events; nor can that idea ever be suggested by any one of those instances, surveyed in all possible lights and positions. But there is nothing in a number of instances, different from every single instance, which is supposed to be exactly similar; except only that after a repetition of similar instances, the mind is carried by habit, upon the appearance of one event, to expect its usual attendant, and to believe that it will exist. This connexion, therefore, which we feel in the mind, this customary transition of the imagination from one object to its usual attendant, is the sentiment or impression, from which we form the idea of power or necessary connexion. Nothing farther is in the case. Contemplate the subject on all sides; you will never find any other origin of that idea. This is the sole difference between one instance, from which we can never receive the idea of connexion, and a number of similar instances, by which it is suggested. The first time a man saw the communication of motion by impulse, as by the shock of two billiard balls, he could not pronounce that the one event was connected: but only that it was conjoined with the other. After he has observed several instances of this nature, he then pronounces them to be connected. What alteration has happened to give rise to this new idea of connexion. Nothing but that he now feels these events to be connected in his imagination, and can readily foretell the existence of one from the appearance of the other. When we say, therefore, that one object is connected with another, we mean only, that they have acquired a connexion in our thought, and give rise to their inference, by which they become proofs of each other's existence: a conclusion, which is somewhat extraordinary; but which seems founded on sufficient evidence. (EU 75-76)

What stands out in this text is Hume's psychological rendering of original causality (impression-to-idea) in belief: "This connexion, therefore, which we feel in the mind, this customary transition of the imagination from one object to its usual attendent, is the sentiment or impression from which we form the idea of power or necessary connexion. Nothing farther is in the case". Note also Hume's psychologizing of his ultimate metaphysical principle and our 'aboriginal cause', Custom, as "this customary transition ...". As well, we stress Hume's characterizing (i) the generation of belief(s) by original causation as "extraordinary" (EU 76) and (ii) the "correspondence" of impression-to-idea as "remarkable" in original causation itself, taken as his "first principle" (T3). Clearly, then, we must distinguish and relate metaphysical and psychological senses of impression-to-idea in original causality: the metaphysical sense of original causality indwells and grounds its generation of belief(s).

       To this end, we shall trace a crucial movement in Hume's doctrine of belief-constructed causation as this movement reveals itself in a series of definitions, explicit and implicit, of belief. These occur in the Treatise (Bk. I., Pt. III: VII-VIII), the two sections being entitled "Of the nature of the idea, or belief" (VII) and "Of the causes of belief" (VIII), respectively. All agree that Hume's Treatise is definitive; and he clearly argues the nature of belief more rigorously there than in the later and derived Enquiry (Sect. V-VII). The same is true for Hume's doctrine of original causality (impression-to-idea) as such, this manifesting itself in our Pt. IV.

       Hume first defines belief (or 'opinion') at T96:

So that as belief does nothing but vary the manner in which we conceive any objects, it can only bestow on our ideas an additional force and vivacity. An opinion, therefore, or belief may be most accurately defin'd. A LIVELY IDEA RELATED TO OR ASSOCIATED WITH A PRESENT IMPRESSION. (Def. 1)

In this definition, Hume asserts a 'relation' or 'association' of an idea with a present impression, but without specifying the nature of that relation at all or as bearing on the idea as 'lively'. Hence, and because further definitions and discussion follow, belief is not "most accurately defin'd" here: the relation is not presented as causal, and moving from impression (cause) to idea (effect). Next, and beginning Section VII ("Of the causes of belief"), Hume grounds belief and this relation causally:

I wou'd willingly establish it as a general maxim in the science of human nature, that when any impression becomes present to us, it not only transports the mind to such ideas as are related to it, but likewise communicates to them a share of its force and vivacity. (T98) (Causal Principle).

Here, in a metaphysical principle lying behind belief, original causality becomes evident as impression-to-idea, such that the '-' here means that the present impression (i) 'transports' the mind to related ideas and (ii) 'communicates' to them a part of its force. This principle passes into what we can term a second definition of belief because of how Hume renders it:

This phenomenon clearly proves, that a present impression with a relation of causation may enliven any idea, and consequently produce belief or assent, according to the precedent definition of it (T101) (Def. 2).

Here, the relation between present impression and idea becomes explicitly causal such that, by enlivening the idea, the impression generates our belief in it. The "phenomenon" by which Hume illustrates is that whereby "the relicts of saints and holy men [present impressions]" "inliven their [superstitious or religious persons'] devotion [idea], and give them a more intimate and strong conception [idea] of those exemplary lives, which they desire to imitate." Note also that Hume claims more than illustration for this "phenomenon": it "clearly proves" belief as expressing original causation in a virtually intuitive or self-evident form, its logical modality being ,not that of contingency, but of a priori necessity, as we shall argue in Pt. IV.

       In any belief, then, we discern the form of original causation in that a present impression stands in causal relation to an idea of x hence believed. What we may call Def. 3 claims this relation to be "certain":

'Tis certain we must have an idea of every matter of fact which we believe. 'Tis certain, that this idea arises only from a relation to a present impression. 'Tis certain, that the belief super-adds nothing to the idea, but only changes our manner of conceiving it, and renders it more strong and lively. (T101) (Def. 3) (we italicize "certain")

Note the words "arises only from" here. What can they mean at this stage of Hume's thinking? Hume reminds us that: "When we are accustom'd to see two impressions conjoin'd together, the appearance [present impression] or idea of the one immediately carries us to the idea of the other" (T102-103). He also reminds us of "my [first] principle, that all our ideas are deriv'd from correspondent impressions" (T105). Now belief requires constant conjunction such that: "We must in every case have observ'd the same impression in past instances, and have found it to be constantly conjoin'd with some other impression. This is confirmed by such a multitude of experiments, that it admits not of the smallest doubt" (T102).

       Before returning to our question about the words "arises only from", let us illustrate the impression - idea relation as Hume intends it in these three latter texts. The "two impressions conjoin'd together" are those of 'fire' and 'burning wood' respectively, occurring such that the impression of fire produces the idea of 'fire', and the impression of 'wood burning' produces the idea of 'wood burning', each idea "correspondent" with its impression. Moreover, we have observed repeated impressions of 'fire' and of 'wood burning' to be "constantly conjoin'd" such that their ideas are constantly conjoined as their respectively corresponding effects.

       . Returning now to our main text in paragraph 29, let "present impression" = 'fire' now burning, and let "idea" = idea (or image) of 'wood burning'. It is clear from paragraph 29, and from our entire discussion of belief so far, that the idea(s) of 'wood burning' has(have) been caused by repeated impressions of 'wood burning'. Hence, when Hume writes that "this idea [wood burning] arises only from a relation to a present impression [fire now burning]", by "arises only from" he must mean not "is caused by" but "is recalled by" the association, through constant conjunction, of the repeated impressions of 'fire' and 'wood burning', each producing its 'correspondent' idea. All along, and especially in his definitions, Hume has argued that, in every case of belief, the 'present impression' merely or strictly enlivens or revivifies an idea (or ideas) already present and previously caused by its(their) impressions. The present impression does not cause the idea believed. Thus, in every case, the present impression "only changes our manner of conceiving it [the idea], and renders it more strong and lively" (T101, Def. 3). In this way, the present impression makes us believe the idea (or matter of fact), here 'wood burning', which idea has, however, been caused by impressions of 'wood burning' over repeated instances. Again, to invoke Hume's own example of our belief in home, we note that the idea(s) of 'home' has(have) been caused by repeated impressions of 'home': the present impression (a nearby land mark) strictly recalls and enlivens, then, the idea of 'home' already present and caused by repeated impressions of 'home'.[20] And so it is for every case of belief.

.       This notwithstanding, we argue that something metaphysically deeper is moving in Hume's thought and texts. Discussing belief "in a fuller light" (T101), Hume writes:

Here 'tis evident, that however that object, which is present to my senses, and that other, whose existence I infer by reasoning, may be thought to influence each other by their particular powers or qualities; yet as the phaenomena of belief, which we at present examine, is merely internal, those powers and qualities being entirely unknown, can have no hand in producing it. 'Tis the present impression, which is to be consider'd as the true and real cause of the idea and of the belief which attends it. We must therefore endeavour to discover by experiments the particular qualities, by which 'tis enabled to produce so extraordinary an effect. (T102, italics added).

Now, having here separated psychologically the "internal" phenomenon of belief from the external domains of impressions and their ideas to which belief adventitiously applies, Hume metaphysically unites belief with those domains: he attributes "so extraordinary an affect" to the "present impression". But exactly what is its effect? In that italicized full sentence, Hume now and astonishingly claims that the present impression not only enlivens the idea hence believed, but also causes that very idea: "... the present impression ... is to be consider'd as the true and real cause of the idea and of the belief which attends it "(italics added). Until now, as noted, Hume presents the present impression as only affecting the idea (previously caused by impressions of which it is the 'copy') so as to enliven it and make us believe it. Cumulatively, the previously cited belief-definitions, explicit and implicit, show this feature and moment of Hume's thought clearly and beyond doubt. But now, equally clear and beyond doubt, is Hume's moving to the insight that the present impression both causes the idea believed and causes our believing that idea.

       This crucial movement in Hume's thought and texts passes into what we may call his fourth definition of belief:

Thus my general position ... [is] ... that an opinion or belief is nothing but a strong and lively idea deriv'd from a present impression related to it (T105) (Def. 4).

Note the words "deriv'd from": as will be shown in Part IV, Hume argues such that 'deriv'd from' = 'caused by'. That is to say, in every case of original causation, the 'corresponding' idea is 'caused by' or 'deriv'd from' a present impression. In Def. 4 above, Hume presents belief, not as the enlivening of the idea believed, but as the relation of derivation or causality itself wherein the believed idea arises from the present impression. In this way, Def. 4 brings to unity the present impression's causing both the idea itself "and" the belief attending it. In Part V, we shall argue so as to clarify this relation.

       As emphasized above, then, Hume moves crucially from claiming that the present impression "only" revivifies the attending idea, thus making us believe it, to the claim that the present impression causes both that very idea itself and our belief in it. Let us now cash out Hume's metaphysical 'cheque' in exemplary causal currency, to realize "so extraordinary an effect": the present impression is of 'fire', and the attendant idea is that of 'wood burning'. These relate, in belief causality, as present 'cause' to believed and expected 'effect'. Hume is thus claiming here that the present impression of 'fire' is "the true and real cause" (T102) not just of the idea of 'fire' as his 'first principle' determines psychologically, but also of the idea of 'wood burning', as that principle now determines metaphysically. These domains of cause and effect now unite, by original causality (impression-to-idea), in the present impression itself, and a priori.

       For empirically, what we have in Hume is this: (i) repeatedly, the impression of 'fire' causes the idea of 'fire'; (ii) repeatedly, the impression of 'wood burning' causes the idea of 'wood burning'; (iii) the constant conjunction of these respective impressions (and their ideas) affects the mind with a burgeoning impression of their associations; (iv) the impression is that of power or necessary connexion, and it causes the idea of power in the mind; (v) a present impression (of 'fire') now readily carries the mind to an idea (of 'wood burning') over against that present impression and caused by the atomic and discrete impression of 'wood burning'; (vi) then, in belief, we schematize 'fire' and 'wood burning' as 'cause' and 'effect' respectively. Let Hume distill the empirical process for us:

But when one particular species of event has always, in all instances, been conjoined with another, we make no longer any scruple of foretelling one [idea] upon the appearance of the other [present impression] and of employing that reasoning, which can alone assure us, of any matter of fact or existence. We then call the one object, Cause; the other, Effect. We suppose, that there is some connection between them; some power in the one, by which it infallibly produces the other, and operates with the greatest certainty and strongest necessity. (EU, 74-75, "then" and "suppose" we italicize)

Note the words "then" and "suppose": after a time of constant conjunction of impressions and their ideas in succession, we come to "suppose" a power in the 'cause' to produce the 'effect' with "the greatest certainty and strongest necessity". A repeated 'conjunction' becomes, in belief, an hypothetical 'connexion'. But belief remains 'internal'; and the elements believed remain 'external' to it whether they be of 'external' or 'internal' sense, physical or mental: the present impression "only" enlivens the believed idea; it does not cause that idea. Empirically, that idea is caused by its own present impression, as when the actual or real impression of 'wood burning' causes the idea of 'wood burning'.

       Yet now, as our paragraphs 32 and 33 with their Hume texts show, Hume advances to the metaphysical insight that the present impression causes both its own idea and, in generating belief, the idea believed. To recall our illustration: the present impression of 'fire' causes both the idea of 'fire' and the idea of 'wood burning'; it generates within itself the ideas, here, of both cause and effect, in original causation, thus: present impression as cause of [idea-A (cause) as causing idea-B (effect)]. Since constant conjunction and hence memory are required here, and are given in the ideas, the present impression ('fire') must produce its own idea ('fire') in relation to those of past conjoined impressions ('fire' - 'burning wood'), in order to produce the idea of the effect ('burning wood'). Here, we speculate, since Hume does not himself offer an explicit analysis of "so extraordinary an effect" of the present impression. It follows, however, that in belief generally the present impression of the cause produces the idea of the effect. And, conversely, the present impression of the effect produces the idea of the cause. For, clearly, the present impression can be either cause or effect, leading inferred belief either 'forward' in time to effect or 'backward' in time to cause.

       We have put the temporal 'forward' and 'backward' in single quotes in order to elicit another crucial movement in Hume's doctrine of belief. Heretofore, Hume has emphasized the role of time in the schematizing of 'cause' and 'effect' as adventitiously carried into experience: past experience in the forms of temporal succession and constant conjunction he has presented as necessary (though not sufficient) for belief to arise. In the atomic sequence of impressions-ideas constituting experience, the cause precedes the effect in time. But now, later in his text (T102-104), Hume arrives, astonished, at the non-temporal immediacy with which the present impression produces belief "by so extraordinary an effect":

From a second observation I conclude, that the belief which attends the present impression ... that this belief, I say, arises immediately without any new operation of the reason or imagination. Of this I can be certain, because I never am conscious of any such operation, and find nothing in the subject on which it can be founded. Now as we call everything Custom, which proceeds from a past repetition, without any new reasoning or conclusion, we may establish it as a certain truth, that all the belief, which follows upon any present impression, is deriv'd solely from that origin. (T102, our italics).

Before noting Hume's illustration of this belief-immediacy, and using relevant texts, let us relate the italicized in the above text: (i) the belief attending the present impression arises immediately; (ii) it is certain; (iii) it derives solely from Custom. Unfortunately, Hume does not relate these claims explicitly to his remarkable claim, just above this text, that the present impression "is to be consider'd as the true and real cause of the idea, and of the belief which attends it" (T102, our italics). Instead, he simply invokes Custom as the remote, because unmediated, cause of this immediacy of belief.

       Hume illustrates the immediacy of belief with a person's meeting a river and foreseeing his drowning if he does not stop at its bank. To argue amply, we must again quote at length:

A person, who stops short in his journey upon meeting a river in his way [present impression], foresees the consequences of his proceeding forward, and his knowledge of these consequences is convey'd to him by past experience, which informs him of such certain conjunctions of causes and effects. But can we think, that on this occasion he reflects on any past experience, and calls to remembrance instances, that he has seen or heard of, in order to discover the effects of water on animal bodies? No surely; this is not the method in which he proceeds in his reasoning. The idea of sinking is so closely connected with that of water, and the idea of suffocating with that of sinking, that the mind makes the transition without the assistance of memory. The custom operates before we have time for reflexion [i.e., remembering]. The objects seem so inseparable that we interpose not a moment's delay in passing from the one to the other. But as this transition proceeds from experience, and not from any primary connexion betwixt the ideas, we must necessarily acknowledge, that experience may produce a belief and a judgment of causes and effects by a secret operation, and without being once thought of. (T103-104, our italics).

Let us note first that Hume's profound text concerns immediate belief. Hence the primary relation is that of present impression to idea. But here the relation is complex, and involves the relation of the primary impression (meeting the river) to several ideas, those of 'water' - 'sinking' - 'suffocating', all of which stand in immediate relation to the present impression and to one another. We add, of course, the idea of 'stopping short' to the ideational complex, obviously a causal series.

       To continue, Hume again reminds us that, while past experience is necessary, it is not sufficient for belief: - As he says in a neighbouring text, "A present impression, then, is absolutely requisite to this whole operation, ..." (T103, our italics). - He continues that "we must necessarily acknowledge" that experience has within it "a secret operation" by which it produces "a belief and a judgement of causes and effects". Now, inasmuch as a present impression "is absolutely requisite" to immediate belief, the 'secret operation' [or elsewhere 'power(s)'] to which Hume here and often refers, must be that impression's immediately producing "the idea, and ... the belief which attends it" (T102, italics added) in that "great connexion" (T4) by which Hume understands the relation of impression-to-idea in original causation, and which we pursue in Part IV. Moreover, here, the original (present) impression (meeting the river) immediately causes, in causal sequence, the ideas 'water' (to) 'sinking' (to) 'suffocating' (to) 'stopping short' and the belief which attends each of these as they together constitute the whole belief stopping that person short at the riverbank.

       It now follows that original causality (as the present impression causing the idea and belief in it in "so extraordinary an effect") mediates Custom as aboriginal cause of particular beliefs, simple and complex. Thus Hume misleads, and obscures his metaphysical thought, in claiming that "all the belief, which follows upon any present impression, is deriv'd solely from that origin [Custom]" (T102, our italics). One scholar writes for many when he remarks that, while Hume is clear "locally", he is vague "globally". Here, we at least clarify Hume's vaguely invoking Custom, by arguing that ultimate principle's mediation in original causation through its extraordinary power: that the present impression (cause or effect) causes both the idea(s) (effect or cause, respectively) and belief in it/them, mediates the logical form by which Custom causes particular, synthetic beliefs and the 'contingent' propositions expressing them.

       As we conclude Part III, one problem remains: it now results that the idea believed has two causes: its own past impression(s) (in Hume's earlier and widely accepted view), and the present impression (in Hume's later "extraordinary" doctrine). (i) Thus, the idea believed ('wood burning') is caused by past impressions of 'wood burning', such that the present impression ('fire') "only" enlivens that idea, making us believe it. (ii) And, the idea believed ('wood burning') is caused both as such and as immediately believed by the present impression ('fire'). Or, complexly but identically: (i) the ideas believed [water (to) 'sinking' (to) 'suffocating' (to) 'stopping short'] are, each respectively, caused by past impressions of these, such that the present impression ('seeing the river at hand') "only" enlivens these ideas, making us believe them, and stop short. (ii) And, these same ideas believed immediately are caused both as such and as immediately believed by the present impression ('seeing the river at hand').

       Now, it is clearly not a matter of our choosing between these two causes of the idea(s) believed. For constant conjunction, involving the repeated generation of ideas by past impressions, is necessary, and the present impression is "absolutely requisite" now in its "extraordinary" effect, for simple or complex belief to arise. Let us take the simple cause of fire burning wood: the idea as effect ("burning wood') is caused both by past impressions of 'burning wood' and by the present impression 'fire' as cause of the effect - idea and belief in it. Since past impressions of 'wood burning' and the present impression of 'fire' both cause the believed idea of 'wood burning', these impressions themselves are inherently related as effect and cause. By containing and grounding within itself as idea of 'fire' (cause) (to) idea of 'burning wood' (effect)], the present impression ('fire') takes up into itself, in its own presentness, the past, present and future of temporal belief-causality. It thus overcomes metaphysically both the temporally atomic succession of 'cause' (to) 'effect' in synthetic and hence 'contingent' empirical relation, and the adventitious character of 'internal' belief carried into 'external' empirical fact.

       This "extraordinary" and astonishing power in the present impression is more evident in complex belief, as, for example, the present impression ('seeing river at hand') causes immediately the ideas in causal sequence ('seeing river at hand' (to) 'sinking' (to) 'suffocating' (to) 'stopping short') and belief in them. We thus again arrive at Hume's doctrine of the "pre-established harmony":

Here, then, is a kind of pre-established harmony between the course of nature and the succession of our ideas; and though the powers and forces, by which the former is governed, be wholly unknown to us; yet our thoughts and conceptions have still, we find, gone on in the same train with the other works of nature. Custom is that principle, by which this correspondence has been effected; so necessary to the subsistence of our species, and the regulation of our conduct, in every circumstance and occurrence of human life. (EU 54-55).

Hume's profound claim comes just after he treats belief as "the whole operation of the mind". He thus treats "custom" in a more psychological manner; and, again, he presents its effecting "this correspondence" in a vaguely direct and hence unmediated way. We have argued, however, that original causality in its "extraordinary" effect mediates the universal form and form of Custom in a modality by which it overcomes time and hence expresses, in Hume's beautiful words, "the eternal establish'd persuasions founded on memory and custom" (TA 632). We turn now to consider the logic of original causation (impression-to-idea) as such.


IV. Original Causation (Impression-To-Idea)

       Defining logic, Hume stresses that "The sole end of logic is to explain the principles and Operations of our reasoning faculty, and the nature of our ideas ..." (TA 646). Hence, it is clear that this paper restricts itself to an investigation of Hume's logic, and its metaphysical foundations. And just as Hume calls the causal origins of sense impressions "unknown", and leaves the corporeal aspects of this matter to the physicists and anatomists, so we too must put them aside. It follows that, working backward, we must ground impressions of sense, as original causes of their ideas, in Custom, Hume's ultimate metaphysical principle. Hence, they stand in immediate relation to Custom. More precisely, original causality, wherein the impression causes the idea, stands in immediate relation to Custom. It thus expresses the universal power of Custom.

       But we have now to establish the causal nature of the impression-to- idea relation. It will now seem obvious in light of Pt. III where we find that the present impression of the cause or effect not only revivifies the idea of the effect or cause, but produces that very idea as well, in Hume's metaphysical logic expressed as a "pre-established harmony'. But, as we shall now see, contemporary scholars either do not treat the impression - idea relation as causal, despite Hume's undeniably presenting it as causal in Section I ("Of the Origin of our Ideas") of Pt. I of Bk. I of the Treatise. - Or else they read back into impression-to-idea belief- or constructed -causality wherein the atomic and sequential domains of impressions with their ideas are sceptically schematized as contingent 'cause' and 'effect', such that the impression is contingent 'cause' of the idea, its 'effect', causal propositions being here synthetic.

       To wit, Anthony Flew thinks the impression-to-idea relation to be a "contingent generalization",[21] despite Hume's claim that this original relation "can never arise from chance" (T4). Again, H.H. Price, reducing causality to believed 'cause' and 'effect', states flatly and in error that "... the causal relation is not a sense-given relation ...":[22] to the contrary, the causal relation is categorically "sense-given". For, as we shall soon see, in original causation, impressions of sense Hume presents as the causes of their own ideas, which hence are their effects. Likewise reducing causality in Hume to believed 'cause' and 'effect',[23] D.G.G. MacNabb calls the impression-to-idea relation an "exhaustive" and "cramping" "dichotomy"[24]. W. Waxman, writing in the journal, Hume Studies, also dichotomizes impressions and their ideas in two "axes of description: the first to represent the qualities proper to perceptions themselves ... and the second to represent phenomenological qualities of our consciousness like veracity/verisimilitude ..."[25] Hence, "a further dichotomization of perceptions as 'impressions' and 'ideas' was necessary".[26] Clearly, then, dichotomizing impression-to-idea, neither MacNabb nor Waxman grasps their relation as causal at all, let alone as extraordinarily causal. Yet again, Gilbert Ryle presents Humean ideas as "traces, copies or reproductions of impressions"[27] but not as their effects in an expressive causal relation to which, as we argue, no real exception exists, or is conceivable.

       Barry Stroud, a distinguished Hume scholar, does present the impression-to-idea relation causally. Yet he, too, can be fairly judged to read belief or constructed causation back into original causality, i.e., to reduce original causality to the schematized 'causality' produced by belief. For he finds "evidence that he [Hume] regards the principle as contingent".[28] Certainly, Hume does not: "The full examination of this question [perception-causality] is the subject of the present treatise, and therefore we shall here content ourselves with establishing one general proposition, that all our simple ideas in their first appearance are deriv'd from simple impressions, which are correspondent to them, and which they exactly represent" (T4, we italicize "establishing one general"). In short, Hume establishes his general proposition in order eventually to explain its power to generate belief-constructed causation.

       Donald Livingston, pre-eminent among Hume scholars, grants that somehow "Impressions are causally prior to ideas but are not prior in the order of intelligibility"[29]. By this latter claim Livingston means Hume's point that sensation (impressions of sense) "arises in the soul originally from unknown causes" (T7), Hume thus leaving its origin to anatomists and natural philosophers. Livingston therefore dissociates causality from impression-to-idea and shifts it problematically to an "act of the mind" where he locates the "force and vivacity" of impressions and ideas: "Since force and vivacity is an act of the mind and since some degree of force and vivacity is internal to every perception, it follows that all perceptions are internal to acts of the mind".[30] Quoting, Hume in support, Livingston italicizes Hume explaining belief as "that act of the mind which renders realities more present to us than fictions ...", and his passage comes from TA269, where Hume also (and more accurately) presents belief "something felt by the mind, which distinguishes the ideas of the judgment from the fictions of the imagination." Note here that while Livingston italicizes "act of the mind" Hume does not, but Hume does italicize "felt" in his later characterizing of belief, where the 'mind' is carried by the force of the present impression to the hence given and revivified idea thus believed. We speak of "mind" here because the utter passivity of the 'mind' in Hume[31] echoes his rejection of it as spiritual substance, and his reducing the mind to his odd and inconsistent reification of the imagination (T,Bk.I, Pt. IV, VI "Of personal identity"). We repeat here that our subject in this paper is Hume's causal logic, not his problematic psychology. Accordingly, force and vivacity occur primarily in impressions of sense as causing their ideas, and not in essentially passive 'acts' of the 'mind'. This fact is absolutely clear as Hume begins his "Of the Origin of our Ideas", wherein he establishes his "one general proposition" concerning original causality:

All the perceptions of the human mind resolve themselves into two distinct kinds, which I shall call IMPRESSIONS and IDEAS. The difference between these consists in the degrees of force and liveliness, with which they strike upon the mind, and make their way into our thought or consciousness. Those perceptions, which enter with most force and violence we may name impressions. ... By ideas I mean the faint images of these in thinking and reason; (T1)

In this pivotal Section, Hume does not at all discuss acts of the mind. It follows that, instead of claiming that "all perceptions are internal to acts of the mind", Livingston should have claimed the reverse, that 'acts' of the 'mind' are internal to all perceptions, where force and vivacity essentially dwell.[32]

       Clearly, then, the best Hume scholars either exclude causality from the impression-to-idea relation or, by reading belief or constructed causality back into it, reduce original causation to the sceptical schematizing of 'cause' and 'effect' which is externally applied to experience, outer or inner. Briefly, we propose two main reasons for superior scholarship's having failed in the face of strong textual evidence (i) that the impression-to-idea relation is causal and (ii) that its causality "amounts to" (Hume's words) demonstrative knowledge. The first reason is the fact that, as we have shown in Pt. III, Hume himself repeatedly (but misleadingly) denies that any causal relation is a priori or demonstrably known. The second is this: since, as we have also shown in Pt. III, the present impression generates both the idea and the belief in it, and this very belief leads us to schematize one empirical event as 'cause' and the other as 'effect' (as Hume says, "we then call the one object, Cause; the other, Effect" [Ecl, 74-75]), we cannot strictly characterize as causal the power by which belief (impression-to-idea) renders our calling one object 'cause' and the other object 'effect' irresistible; and yet this power shows itself as a prior kind and order of causation. In short, the a priori causality whereby belief (impression-to-idea) causes empirical 'causality' gets paradoxically lost in its effect: the empirical 'causality' which it causes a priori. Accordingly, as we document above, scholars might (mistakenly) or might not read empirical or belief 'causality' back into the impression-to-idea relation, original causation as we argue.

       Let us now go directly to Hume's crucial "Of the Origin of our Ideas", where the causal nature of the impression-to-idea relation readily appears as undeniable. First, Hume makes it very clear that impressions manifest force: "Those perceptions, which enter with most force and violence, we may name impressions; and under this name I comprehend all our sensations, passions and emotions as they make their first appearance in the soul" (T1, "force" and "violence" we italicize). He then tells us that "By ideas I mean the faint images of these in thinking and reasoning, such as ... all the perceptions excited by the present discourse ..." Immediately, then, Hume asserts a relation of force, or even violence, between impressions and ideas. The relation involves power, and quite in advance of functioning belief - constructed causality. Now, having distinguished simple and complex impressions and ideas (in both cases, complexes being compounded divisibly of simples), Hume writes: "Let us consider how they stand with regard to their existence, and which of the impressions and ideas are causes and which effects (T4, italics added), adding later that "the existence of the one has a considerable influence upon that of the other" (T4). This "influence", involving a "constant conjunction" over "an infinite number of instances", cannot be contingent, "but clearly proves a dependence of the impressions on the ideas, or of the ideas on the impressions" (T4-5, italics added). Citing the "order of their first appearance" (85) as decisive here, Hume claims importantly that "constant experience" reveals that "the simple impressions always take the precedence of their correspondent ideas, but never appear in the contrary order" (T5, italics added). Hence the simple impressions are indisputably the causes of their corresponding ideas: the precedence of impression over idea then clearly proves a dependence ... of the ideas on the impressions" (T5, italics added). Who now can doubt that Hume understands the impression to cause its corresponding idea? This causal dependence works not just in simple cases, but "as the complex are formed from them, we may affirm in general, that these two species of perception are exactly correspondent (T4, italics added).

       But what kind of causal connexion prevails, then in what we have called throughout original causality (impression-to-idea)? As promised earlier, we shall now argue that original causality manifests what "amounts to" (Hume) demonstrative knowledge; indeed, it is self-evident a priori. Livingston rightly notes and brilliantly exploits Hume's commitment to 'common life', in his narrative approach to the development of Hume's thought. So, right at the start, Hume invokes something immediately known in common life: "Everyone of himself will readily perceive the difference betwixt feeling [impression] and thinking [idea]" (T1-2, italics added). He next emphasizes both the difference and the virtual identity of "feeling" and "thinking": first, he tells us that "they are in general so very different, that no-one can made a scruple to rank them under distinct heads, and assign to each a peculiar name to mark the difference [n.1: "impression and idea"]" (T2, italics added). Hume next tells us that "the first circumstance, that strikes my eye, is the great resemblance betwixt our impressions and ideas in every other particular, except their degree of force and vivacity" (T2, italics added). In view of the pivotal text which follows, we have here what is surely an identity-in-difference between impression and idea:

The one [ideas] seem to be in a manner the reflexion of the other; so that all the perceptions of the mind are double, and appear both as impressions and ideas, when I shut my eyes and think of my chamber, the ideas I form are exact representations of the impressions I felt; nor is there any circumstance of the one, which is not to be found in the other. In running over my other perceptions, I find still the same resemblance and representation. Ideas and impressions appear always to correspond to each other. This circumstance seems to me remarkable and engages my attention for a moment (T2-3, italics added).

Now, since the impression-idea relation is indisputably both causal and non-convertible, the impression as cause differentiates into itself as effect. Hence, while Hume calls both impressions and ideas "perceptions", we can now affirm that the terms 'perception' and 'experience' refer properly or rigorously to the reflexive unity-in-difference expressed as original causality (impression-to-idea). They are, so to speak, two sides of the same coin. In short, original causality is the condition a priori through which perception or experience is made possible, and actually occurs.

       The language of unqualified certainty pervades Hume's understanding and presentation of impression-to-idea. This the reader has already encountered as Hume explains the certainty of immediate belief in texts cited in paras. 36 and 37 of this paper. But in the present section of the Treatise, where the causality of impression-to-idea as such is "established", we find that a prioristic certainty. Speaking of simple perceptions, the elements of our experience, Hume writes: "After the most accurate examination, of which I am capable, I venture to affirm, that the rule here holds without any exception, and that every simple idea has a simple impression which resembles it; and every simple impression a correspondent idea" (T3, italics added). Now, while Hume grants that "'tis impossible to prove by a particular enumeration of them" that such is the case with all our impressions and ideas, he does virtually deny the necessity of such an exhaustive enumeration:

Every one may satisfy himself in this point by running over as many as he pleases. But if anyone should deny this universal resemblance, I know no way of convincing him, but by desiring him to show a simple impression, that has not a correspondent idea, or a simple idea, that has not a correspondent impression. If he does not answer this challenge, as 'tis certain he cannot, we may from his silence and our own observation establish our conclusion (T3-4, italics added).

From the standpoint of common life, then, Hume effectively claims here that a causal relation (metaphysically) self-evident (though a pre-established harmony) gradually emerges as one satisfies himself "by running over as many [instances] as he pleases". No scepticism and no problem of induction are present here.

       We come now to the text which has inspired the title of this paper. Having enunciated his "one general proposition", Hume writes that:

In seeking for phaenomena to prove this proposition, I find only those of two kinds; but in each kind the phaenomena are obvious , numerous and conclusive. I first make myself certain, by a new review, of what I have already asserted, that every simple impression is attended with a correspondent idea, and every simple idea with a correspondent impression. From this constant conjunction of resembling perceptions I immediately conclude, that there is a great connexion betwixt our correspondent impressions and ideas, and that the existence of the one has a considerable influence upon that of the other. (T4, italics added).

Now, apart from the infinitive "to prove", what stands out in this text as italicized is Hume's claim that "I immediately conclude that there is a great connexion betwixt our correspondent impression and ideas..." But in none of the best recent literature on impression-to-idea in Hume is the immediate concluding of "a great connexion" at all recognized or taken up. Note as well that the word here is "connexion", and not "conjunction", and that, as explained in Pt. III, constant conjunction is necessary but not sufficient to establish necessary connexion or belief, for the schematizing of experience as 'cause' and 'effect': original causality alone as impression-to-idea suffices to generate necessary connexion or belief. Clearly then, and despite the scholarship as documented, original causality as such grounds and expresses that necessity as a "great connexion" to which Hume grants no real exception.[33]

       It is true that, in the text above, Hume does appear to derive this great connexion from "constant conjunction", and hence to suggest a contingent relation between impression and idea, i..e., he seems here as elsewhere to reduce original to belief-constructed causation. But that is not really so: for the universal certainty which he ascribes to this relation is now manifest. And, in para. 51, above we see him virtually deny the necessity of an exhaustive enumeration of instances: one may enumerate as many instances "as he pleases". But we cite here a text which consolidates our point:

The constant conjunction of our resembling perceptions, is a convincing proof, that the one are the causes of the other; and this priority of the impression is an equal proof, that our impressions are the causes of our ideas, not our ideas of our impressions (T5, italics added).

This text complements that in para. 51 above, precisely, "constant conjunction" here equalling "as many [instances] as he pleases" there. In this fact, Hume is saying that a constant conjunction of impression-to-idea is sufficient but not necessary to establish impression-to-idea, but also that the "[a]-priority of the impressions" equally proves the causal relation in any one or more instances of it. In other words, as forcefully "a reflexion", the relation is essentially self-evident. Its necessity thus contrasts with the context in which Hume explains the role of constant conjunction in the arising of the original impression (and hence idea) of power or necessary connexion. There constant conjunction is necessary but not sufficient to produce that idea. Only the arising of the original impression of power (as the mind repeatedly associates one object with another in constant conjunction) is there sufficient to produce, as its own a priori, the idea of power.

       Before putting original causation and belief causation (its product) into direct relation, let us remark briefly on Hume's treatment of time here. In arguing for a causal relation between impression and idea, Hume does claim, it seems, a temporal priority of impression to idea, in relation to their distinctness. For example in his Abstract to the Treatise he writes that "Priority in time, is therefore another requisite circumstance in every cause" (TA 649). But in the definitive treatment of impression-to-idea (T1-7), Hume is ambiguous about the "order" of impression and idea. It is not clearly temporal, but appears on balance to have a more logical character:

That I may know on which side this [causal] dependence lies, I consider the order of their first appearance; and find by constant experience that the simple impressions always take the precedence of their correspondent ideas, but never in the contrary order. To give a child an idea of scarlet or orange, of sweet or bitter. I present the objects, or in other words, convey to him these impressions' but proceed not so absurdly as to endeavour to produce the impression by exciting the ideas (T5, italics added).

Here, neither "order" nor "precedence" nor "contrary order" is said to be temporal, or implied to be so. Note also the words "not so absurdly": for Hume, absurdity is contradiction. Elsewhere, he writes that "wherever a demonstration takes place, the contrary is impossible, and implies a contradiction" (TA 650). In this present case, it is absurd or contradictory that impression and idea appear in "the contrary order", such that the idea of scarlet or orange could produce the original impression of scarlet or orange. Now to this argument we add a final point: when Hume distinguishes impression and idea in their relation, he insists, repeatedly and without exception, that they have a "great resemblance", and this "in every other particular, except their degree of force and vivacity" (T2, italics added). He never adds "and their temporal order". Since we may now infer that "except their degree of force and vivacity" refers to the causal and logical differentiation of original impression into its idea, it is persuasive that time itself disappears into that differentiation, into that immediate relation of identity-in-difference. It is fitting, then, that what now "amounts to" a logical relation of impression-to-idea should as such manifest "the eternal establish'd persuasions" (TA 632) which we earlier attributed to belief as thus generated (para. 42).

       Let us now compare original and belief or constructed causality more directly. First, original causality is immediately concluded rather than mediately applied, as is belief causality, through belief to phenomena in themselves atomistically related and in temporal sequence. Second, original causality is logically necessary, rather than psychologically 'contingent' as is belief causation. In these ways, impressions must cause their ideas; and ideas, as such, must be effects of their impressions. Again, in original causation, we have identity-in-difference: the original impression differentiates causally, by causing its idea as identical in content but different in order and form as shown in lesser force and vivacity only. Hence, where in original causation, the impression differentiates logically into its idea, in belief or constructed causality, the 'cause' divides into the 'effect' in the sense that the 'cause' (impression of fire) is atomistically succeeded by the 'effect' (impression of wood burning), their ideas doing likewise. And here, a necessary connexion a priori is externally imposed through subjective belief, and is not perceived as present in the 'outer' or 'inner' phenomena themselves. Hence, Hume can and does say here that any 'cause' can 'produce' any 'effect', and that any 'effect' can arise from any 'cause'. But, and this is crucial, Hume never says or implies that any original impression can cause any idea, or that any idea can be the effect of any original impression: hence, an original impression of 'red' cannot conceivably produce an idea of 'blue'; nor, more generally, can an idea of sound be caused by an original impression of sight.

       In terms of judgments or propositions, then, we can say that all propositions asserting original causality (or indeed belief itself where the present impression of the cause, e.g., not only enlivens but causes the idea of the effect) are analytic. And, accordingly, all propositions asserting constructed or belief causation are, as Hume himself virtually says, synthetic, and can be denied without contradiction. But note that the analyticity in original causation is, as forcefully reflexive, expressive and not tautological or inert. Hence, the proposition "All original impressions produce representing ideas" we cannot deny without contradiction, since by nature, essence or definition, impressions impose themselves by producing their representing ideas. But the proposition 'Bread always nourishes us', being synthetic, we can deny without contradiction, since we can here perceive no necessary connexion: bread can conceivably choke us or make us ill.

       It follows from the entire argument that original causality is prior to constructed causality, and of a different and metaphysical level. Moreover, original causality cannot be reduced to constructed causality; for it supplies belief itself and the idea of power or necessary connexion without which constructed causality would be impossible a priori. Once again:

We then call the one object, Cause; the other, effect. We suppose that there is some connexion between them; some power in the one, by which it infallibly produces the other, and operates with the greatest certainty and strongest necessity (EU 75, italics added, except for Hume's own "cause" and "effect").

Here, we see, though externally applied, the figure or form of original causality present within constructed 'causality'. Although the necessity here is synthetically supposed, rather than analytically and expressively certain though forceful "reflexion", the language and content of infallible production, greatest certainty and strongest necessity metaphysically irradiate this passage. For while Hume here denies rational necessity to the schematized or constructed 'cause' 'effect' relation, of original causality (impression-to-idea), or belief itself, he claims this:

We infer a cause immediately from its effect; and this inference is not only a true species of reasoning, but the strongest of all others, and more convincing than when we interpose another idea to connect the two extremes. What we may in general affirm concerning these three acts of the understanding ["conception, judgment and reasoning"] is, that taking them in a proper light, they all resolve themselves into the first [conception], and are nothing but particular ways of conceiving our objects. Whether we consider a single object or several; whether we dwell on these objects, or run from them to others; and in whatever form or order we survey them, the act of the mind exceeds not a simple conception; and the only remarkable difference, which occurs on this occasion, is, when we join belief to the conception, and are persuaded of the truth of what we conceive (T97, n.1, italics added, except for the square-bracketed).

In this passage, Hume reduces the "judgment" ("the separating or uniting of different ideas") and "reasoning" (the use of mediating ideas to show how others unite or separate) "of the schools" to belief itself in the conception. That is, he reduces rational "acts" of mind to original causation itself. In original causation, generating belief, as we argued above, the present impression of the cause (or effect) not only enlivens the idea or conception of the effect (or cause, but produces that idea, hence uniting reflexively or a priori "the two extremes", cause and effect. Moreover, he presents original causality here as "not only a true species of reasoning", but as "the strongest of all others". In this reduction of all rationality to original causality as belief, which Hume clearly venerates as most rational, the impression-to-idea relation more than "amounts to" demonstrative knowledge or "reasoning": as belief, original causation replaces "reasoning" in as much as an immediate cognition replaces "reasoning", which for the "schools" and logicians involves the use of "other ideas" to mediate "the separating or uniting of different ideas ... [by showing] the relation they bear to each other". Clearly then, Hume identifies true reason with belief as such, and grounds it metaphysically in original causation.

       In concluding this Part, we shall note certain matters concerning original causation, and consolidate our claims in relation to Hume's doctrine of "the pre-established harmony". In Part V we shall briefly focus on original causation as it mediates Custom and belief-constructed causality.

       There are two forms of original causation, one generating belief, the other not. When an original impression reflexively generates only its own idea, we do not have belief: we have belief only as this relation moves from what is present to what is absent, from cause to effect or the reverse. Thus belief is not present when the impression of 'fire' generates reflexively its idea of 'fire'; nor is it present as the impression of 'wood burning' causes reflexively its idea of 'wood burning'. Belief occurs only as the present impression of 'fire' reflexively causes both its idea of 'fire' and the idea of 'wood burning', which reflexively is its own also, within the pre-established harmony thus revealed.

       Now, keeping the illustration of 'fire'-to-'wood burning' before us, let us note that the non-believed (as effect) idea of 'wood burning' comes originally from the impression(s) of 'wood burning': but the believed idea of 'wood burning' as the effect of 'fire' is both caused and enlivened by the present impression of 'fire'. And, as we have just seen in para. 57 above, belief, having taken demonstrative reasoning into itself, is a priori. We therefore have this situation metaphysically: the idea of 'wood burning' is originally caused by both the impression(s) of 'wood burning', and by the present impression of 'fire'; and as not-believed effect of 'wood burning'), and as believed (effect of 'fire'), respectively. It follows, therefore, that this original commonality through which the idea of 'wood burning' is caused by both the impression of 'wood burning' and the present impression of 'fire', puts the impression(s) of 'fire' and the impression(s) of 'wood burning' into a metaphysically (though not psychologically) and expressively analytic relation. That is to say, the "irradiation" (para. 57) by original causation of belief-constructed causation prevails as, in the latter, "We suppose ... some power-in the one ['cause'], by which it infallibly produces the other ['effect'], and operates with the greatest certainty and strongest necessity" (EU 75, italics added). Psychologically, then, the sequences of 'inner' and 'outer' impressions and of their ideas as such remain in external relation as causally schematized; and the propositions expressing them as so schematized remain synthetic and hence deniable without contradiction. Hume's scepticism thus focusses psychologically on the 'causality' of original discrete impressions as such and of their discrete ideas as such, as these arise in parallel sequence taken as temporal and/or spatial order. But, metaphysically, and concerning original causation as such in its two forms, Hume evinces no real scepticism at all: the causal relation whereby, in either form, original impression imposes itself with reflexive force as idea on the 'mind', remains logically sacrosanct for him.

       In this Part IV, then, we have argued the logic of original causality (impression-to-idea) as such to involve a reflexive identify-in-difference. This identity-in-difference confirms the same found in Part III as we found Hume's doctrine of belief to arrive remarkably at the insight that the present impression (cause or effect) both causes and enlivens the hence believed idea (effect or cause) as well as causing its own idea in an immediacy that astonishes Hume. Moreover, we interpreted Hume's example of one's meeting a river suddenly (paras. 37 and 38 above) to show a cross-section of the pre-established harmony: the present impression 'river' immediately causes and enlivens the hence believed ideas of 'water' (to) 'sinking' (to) 'suffocating' (to) 'stopping short'. But since, as we have just argued, belief now pre-empts or constitutes demonstrative knowledge, a sublime cross-section and illustration of this harmony avails us. Hume cites it when explaining abstraction in mathematics as a function of belief:

For this is one of the most extraordinary circumstances in the present affair, that after the mind has produc'd an individual idea, upon which we reason, the attendant custom, reviv'd by the general or abstract term [present impression], readily suggests any other individual, if by chance we form any reasoning, that agrees not with it. Thus shou'd we mention the word, triangle [present impression], and form the idea of a particular equilateral one to correspond to it, and shou'd we afterwards assert, that the three angles of a triangle are equal to each other, the other individuals of a scalenum and isosceles, which we overlook'd at first, immediately crowd in upon us, and make us perceive the falsehood of this proposition; tho' it be true with relation to that idea, which we had, form'd (T21, Hume italicizes "that the three, etc."; we italicize the other texts).

We note crucially that Hume solves the problem of false belief here, and by implication elsewhere: beliefs which accord with the pre-established harmony are true, beliefs disaccording with that sublime harmony are false.

       The argument for original causality (as metaphysically distinct from both Custom and belief-constructed causation) is now complete. That original causation mediates Custom's causing or necessitating belief-schematized causality is now quite evident as well. In a very brief Part V, however, we shall conclude by consolidating this mediation as it relates to a cognate issue in recent scholarship.


V. Aboriginal Causation: Custom-To-(Impression-To-Idea)-To-(Belief-Constructed Causality).

       Scholars variously observe that Hume reveres Custom. The reader will now agree that Hume also reveres original causation as it generates belief directly and belief-constructed causation indirectly. Indeed, Hume marvels at the power of the present impression (whether in mathematics, poetry, history, etc.) to summon a virtual infinitude of ideas along with the ideas immediately believed, that infinitude confirming, denying or qualifying the belief(s) in question. Hume's common reverence for Custom and original causality, in relation to the generation of the totality of 'beliefs' expressed under belief-constructed causality, can be explained only as original causation's mediating Custom's generating the entire fabric of 'beliefs' which themselves underwrite our common life. For we have seen that, while original causation causes belief which articulates as the causally schematized 'beliefs' of common life,. Hume also repeatedly appeals to Custom as the obscure and seemingly ultimate cause of 'beliefs' themselves. Hence we may now call Custom the remote cause, and original causation as impression-to-idea the mediating cause, of belief-constructed causality and the multitudinous 'beliefs' culturally expressing it.

       This rendering is more than speculatively plausible; it is surely true. For assuming it now established that original causation forces us to schematize atomistic experience as 'cause' and 'effect' in multitudinous 'beliefs', let us consider the Custom-side of original causation: Hume presents the original impressions, causing ideas believed, as not just the causes of such ideas and their enlivening, but also as effects themselves. Thus, while original impressions cause their ideas in forceful reflexion, they do not cause themselves. As impressions of sensation, they arise "in the soul originally, from unknown causes" (T7, italics added). These causes cannot be bodies (for 'outer sense') or minds (for 'inner sense'), since Hume critically rejects these two as material and spiritual substances or substrata respectively, and as continuants in any real sense. And since he rejects these, his leaving the origins of original sense impressions to natural philosophers and anatomists is indeed problematic. But metaphysically, the causes of original sense impressions cannot it seems, be plural: they must be one and universal, namely Custom, which Hume always presents as a "principle of human nature, which is universally acknowledged, and which is well known by its effects" (EU 43).

       In Part III, we promised to offer a later clarification of Hume's claim, regarding belief, that the original impression (cause or effect) revivifies or enlivens the idea (effect or cause) thus believed. Recall that we traced in Part III, a crucial development wherein Hume advances from the claim that the original or present impression merely enlivens an idea otherwise caused by its original impression(s) (as when the impression(s) of 'wood burning' cause the idea of 'wood burning') to the doctrine that the original impression ('fire') causes both the idea itself ('wood burning') and the enlivening of it, such that we cannot but believe it, and the idea believed remains utterly self-same as believed. Our clarification of Hume's developed doctrine is, therefore, what it now must be: the expressively reflective and analytic character of impression-to-idea in original causation as such (impression 'fire'-to- idea 'fire') carries metaphysically into impression-to-idea in original causation as generating belief itself, such that: (present impression 'fire'-to-idea 'fire' and idea 'wood burning' - hence necessarily believed). Belief, then, uniting cause and effect a priori, is self-evident as "not only a true species of reasoning, but the strongest of all others" (T97, n. 1). And as self-evident, it justifies itself under Custom.

       Our concluding that belief qua self-evident justifies itself brings us at once to this very question as treated in current scholarship. Since even the best Hume scholars recognize only Custom on the one hand and belief-constructed 'causation' on the other, the question of justifying belief becomes acute as the question of the relation of a remote and obscurely invoked Custom to individual 'beliefs'. In a new article, entitled "Human Justified Belief", John W. Carroll pursues this issue by reference to Hume's "Rules by which to judge of causes and effects" (T, Bk. I, Pt. III:XV)[34]. Also, he critically engages Beauchamp and Rosenberg, who in a recent work, pursue this matter as well.[35] Carroll also cites, for those interested, an article by M. Costa: "Hume and Justified Belief".[36] Against Beauchamp and Rosenberg, who hold that Custom alone without justification "by application of the rules" is capricious, Carroll invokes Hume's "great reverence for custom and simple inference. This reverence is at odds with any claim to the effect that unsupplemented custom is epistemically poor".[37] Carroll proceeds to link Custom with the application of the rules, and not to separate them, hence not discrediting Custom alone, as do Beauchamp and Rosenberg. For the latter, who put Custom to one side, there is no mediation of Custom with the multitude of 'beliefs' hence needing justification. Rather, they simply apply Hume's rules to the sequences of experience as these atomistically occur, doing so externally, of course. But Carroll betters the approach of Beauchamp and Rosenberg by seeking a mediation: he argues correctly that Custom is somehow present in the application of the rules to experience, and cites Hume's claim in rule 5 that "like effects imply like causes" (T. 174). Yet Caroll's effort fails as he continues: "When we apply the rules, we are just as much reasoning on animal faith and instinct as in simple causal inference."[38] For here, on the one hand, he sounds like Hume himself grounding 'beliefs' on an obscurely invoked and remote Custom presented as "instinct". And, on the other hand, he here tends to make of the rules as applied, just a set of 'beliefs' at the belief-constructed level of the 'beliefs' to be justified by the very application of the rules themselves. His effort to mediate Custom and our multitudinous 'beliefs' thus flies apart in both directions; and we are left again without a causal mediation. Now, these scholars, who to their credit would move Hume beyond that stereotyped scepticism dogging him, clearly place their hopes and efforts in applying Hume's rules to 'beliefs' themselves. In this, they are joined by Fred Wilson, who, in his new book, takes essentially the same approach. Let us therefore look briefly at Hume's "Rules by which to judge of cases and effects", and their context:[39]

       Soon into Section XV ("Rules, etc)., we find its context to limit decisively the application and the value of Hume's rules. The context is such that "Any thing may produce anything" (T173), namely the domain of synthetic impressions and their ideas occurring in paralleled atomic sequence, temporal and/or spatial. Moreover, it is clear that the most that the empirical application of these rules can do is to establish constant conjunction, which itself falls short of establishing belief. Yet, in setting constant conjunction as the end of the rules' application, Hume himself misleads: he first claims "that the constant conjunction of objects determines their causation". He then states that "where objects are not contrary, nothing hinders them from having that constant conjunction, on which the relation of cause and effect totally depends" (T 173, italics added). Now these statements imply that a constant conjunction in experience is both necessary and sufficient to produce belief-constructed causation. We need not now explain, but merely note however, that constant conjunction is necessary but not sufficient to generate that belief which is sufficient to produce the 'cause' and 'effect' of thus schematized experience: the idea of necessary connexion generated only by a present impression of the mind's constantly associating one 'object' with another (original causation) alone adds sufficiency to constant conjunction. In this Section, Hume makes no mention of original causation generating belief, but instead proceeds to list his rules, the first four of which confirm our critical point:

1       The cause and effect must be contiguous in space and time.
2       The cause must be prior to the effect.
3       Their must be a constant union [i.e., conjunction, not connexion] betwixt the       cause and effect ...
4       The same cause always produces the same effect, and the same effect never       arises but from the same cause ... (T173).

Clearly, the first three rules simply list contiguity, succession and constant conjunction as therefore necessary but not sufficient to cause belief-constructed causality. Rule 4 simply restates "constant conjunction" in Rule 3 as "always". The remaining rules, presupposing rules 1-4, simply offer experimental cautions, and refinements of the rules, such as Bacon had proposed much earlier.

       It follows that a set of rules, the application of which cannot itself yield belief, can hardly be understood to justify belief, and to do so externally, since the synthetic orders to which these rules apply are such that belief is brought adventitiously to them. Belief, then, as the causally reflexive relation of present impression-to-idea (original causation) justifies itself as grounded in a pre-established harmony; and Hume thereby escapes an infinite criteriological regress. In this, Hume resonates with Spinoza's doctrine of philosophical method as the causally reflexive knowledge - the knowing that one knows - of adequate and true knowledge.[40]

       It also follows that Hume's criterion of the meaning of ideas - a criterion leading to the verification principle of A.J. Ayer and other logical or empirical positivists - grounds itself in the impression-to-idea relation of original causation as it mediates Custom and belief-constructed causality:

Accordingly, whenever any idea is ambiguous, [one] has always recourse to the impression, which must render it clear and precise. And when he suspects that any philosophical term has no idea annexed to it (as is too common) he always asks from what impression that pretended idea is derived? And if no impression can be produced, he concludes that the term is altogether insignificant ... and it were to be wished that this rigorous method were more practiced in all philosophical debates (TA649, central italics are Hume's, others are ours).

Hume's criterion of meaning, where ideas as validated refer to any content of thought proceeding from original impressions, is thus metaphysical and a priori. As we have argued it, this conclusion can be rejected only by rejecting, as Ayer does, the question of the origin of ideas as (positivistically) misguided. And it is now clear that original causation (impression-to-idea), in distinctively mediating Custom's metaphysically causing belief-constructed causality, mediates the human and common universe of effective meaning as well. This mediation, as both productive and semantic, is lost to the scholars reviewed above, whether they treat impression-to-idea causally or not: if they do, they collapse its causality into the 'causality' which is belief-constructed, and hence they collapse the mediation into one causal pole to be mediated. If they do not, what they do not treat causally (impression-to- idea) cannot a fortiori causally mediate Custom and belief-constructed 'causality'.

       Against Wilson and others, then, our "Prussian" Hume stands forth as a serious, if constrained, metaphysician. As such, Hume proposes a "true" metaphysics. Moreover, as argued here, the causal role of original causality (impression-to-idea) insofar as it imposes belief on what "then" become the 'causes' and 'effects' of human experience, anticipates the role of the Kantian concept or category of 'cause-effect' as it analogically schematizes experience. In his article, "Hume's Playful Metaphysics", Moses[41] elicits that sceptical and self-amused Hume who writes that "my [speculative] follies shall at least be natural and agreeable". But, soon after, and defending philosophy against superstition, Hume claims that: "Where reason is lively, and mixes itself with some [speculative] propensity, it ought to be assented to" (T270, italics added). We argued above, in part IV, that reason is most "lively" as, through original causation, it generates that belief which causes the "beliefs" sustaining common life. Hence, we reply to Moses that Hume's doing metaphysics is half fun, but whole earnest.

       Concluding, we ask: Does Custom, Hume's "ultimate" principle, itself have a cause? Since he grants that possibility, we shall let Hume answer our question in a beautiful text:

The order of the universe proves an omnipotent mind; that is, a mind whose will is constantly attended with the obedience of every creature and being. Nothing more is requisite to give a foundation to all the articles of religion, nor is it necessary we shou'd form a distinct idea of the force and energy of the supreme Being (TA 633, n. 1; we italicize "proves" and "obedience").

It here follows that, in Hume's metaphysical logic, original causation mediates Custom, and belief-constructed causality, by creating a priori that belief which is itself obedience to that divine mind.

Memorial University of Newfoundland



[1] Hume's definitive work is, of course, his A Treatise of Human Nature. Here, we shall use the Oxford second edition of the Treatise, edited by L.A. Selby-Bigge and revised by P.H. Nidditch, reprinted in 1985. We shall follow scholarly practice, referring to the Treatise as, bracketed 'T' + page number of quotations and references, e.g., (T 103). Also, we shall use the combined edition, David Hume: Enquiries concerning the Human [1]Understanding and Concerning the Principles of Morals, ed. L.A. Selby-Bigge, 2nd ed., Oxford University Press, 1902. We shall refer to these Enquiries as bracketed '(EU 95)' and '(EM 207)' noting page numbers as illustrated. Paragraphs are numbered in square brackets.

[2] Hume, but neither Locke nor Berkeley, distinguishes 'impressions' from 'ideas'. Indeed, Hume claims thereby to "restore the word, idea, to its original sense, from which Mr. Locke had perverted it, in making it stand for all our perceptions". And by the term 'impression' Hume "would not be understood to express the manner, in which our lively perceptions are produced in the soul, but merely the perceptions themselves; for which there is no particular name in the English or any other language, that I know of" (T2, n.1). Suffice it at present to note that by impressions Hume means perceptions entering our consciousness "with most force and violence" (T1), by ideas "the faint images of these in thinking and reasoning".

[3] G.W.F. Hegel, Lectures on the History of Philosophy, Vol. III (New York: Humanities Press, 1977), p. 372.

[4] Hume paid dearly for his scepticism to which he was and is reduced. Even Mill, his great disciple, wrote this: "Hume possessed powers of a very high order; but regard for truth formed no part of his character. He reasoned with surprising acuteness; but the object of his reasonings was, not to obtain truth, but to show that it is unattainable. His mind, too, was completely enslaved by a taste for ... that literature which ... seeks only to excite emotion". And Dr. Warburton wrote to Hume's publisher that "a wickeder mind, and mor obstinately bent on public mischief, I never knew". Several contemporary works, treating Hume holistically, would move Hume beyond unleavened scepticism. Notable among them are Barry Stroud's Hume Routledge: London and New York, 1977), Donald Livingston's Hume's Philosophy of Common Life (University of Chicago, 1984), and Fred Wilson's Hume's Defence of Causal Inference (University of Toronto, 1997). But none of these scholars arrives at the causal metaphysics argued here, and in particular at the causality of the crucial impression - idea relation. We shall discuss them, and others, as relevant and in due course.

[5] A.J. Ayer, Hume (Oxford, 1980). The words 'being', 'existence', 'metaphysics' do not appear in Ayer's index, although Hume has doctrines concerning all of them.

[6] (EU 12).

[7] Ayer (Ch. IV., "Cause and Effect"), trying to explain why Hume, having claimed that "there can be no such thing as chance in the world", thereby contradicts "his having been at considerable pains to show (T78ff.) that the generally received maxim that 'whatever begins to exist, must have a cause' is neither intuitively nor demonstratively certain", writes this: "The only explanation seems to be that the propositions that 'every event has a cause' and that 'the course of nature continues always uniformly the same' were regarded by Hume in the light of natural beliefs. They cannot be proved, but nature, is so constituted that we cannot avoid accepting them" (pp. 70-71, "beliefs" italicized).

[8] Distinguishing impressions of "Sensation" from those of "Reflection" (T7-8), Hume claims that the "first kind arises in the soul originally from unknown causes", which latter Hume leaves to anatomists and natural philosophers (T8). Since, for Hume, all ideas arise ultimately from impressions of sense, we call the impression-to-idea relations "original causality". Now, while Hume leaves the physical origins of sense impressions to anatomists and physicists, it is abundantly clear that 'Custom' or 'Nature' metaphysically grounds the impression-to-idea relation and thus belief, its effect. Hence, to adopt a word where "original" is pre-empted, we call Custom/Nature "aboriginal" cause to capture Hume's sense when he speculates that "Perhaps, we can push our enquiries no farther or pretend to give the cause of this cause [Custom]; but must rest contented with it as the ultimate principle, which we can assign ... (EU 75). Finally, we capitalize 'Custom' and its equivalent 'Nature' to distinguish this cause in its aboriginal sense from Hume's use of custom(s) and habit(s) (uncapitalized) to mean the many 'beliefs' by which we live at the level of constructed causality. In so doing, we follow Hume who himself at times uppercases CUSTOM (and HABIT).

[9] Hume's view of contingency is remarkably similar to that of Spinoza, to whom Hume is increasingly related and compared. Spinoza holds that "a thing can be called contingent only in respect of a defect in our knowledge" (Eth. II, Prop. 33, Sch. 1), clarifying this later in Df. III of Eth. IV: III. " Particular things I call contingent in so far as, while attending to their essence alone, we find nothing [no cause] which necessarily posits their existence, or which necessarily excludes it". And metaphysically, Spinoza rejects contingency (Eth. I, Prop. XXIX), as does Hume. For those interested in Spinoza - Hume, the journal, Hume Studies, founded in 1975, contains several papers: R. Popkin's "Hume and Spinoza" (Vol. 5, No. 1); W. Klevers "Hume contra Spinoza?" (Vol. 16, No. 1); F.J. Leavitt's "Hume Against Spinoza and Aristotle" (Vol. 17, No. 2); A.C. Baiers "David Hume: Spinozist" (Vol. 19, No. 2). We shall return briefly to Hume-Spinoza, a longer treatment exceeding our scope here.

[10] Hume, (E U 55-56).

[11] Douglas Gasking, "Causation and Recipes" in Human Understanding: Studies in the Philosophy of David Hume, ed., A. Sesonski and N. Fleming (Wadsworth Publishing Co. Inc., 1965), pp. 60-68.

[12] D.G.G. MacNabb, "Hume" in The Encyclopaedia of Philosophy, ed., Paul Edwards (MacMillan Publishing, 1967) Vol. IV, pp. 74-90.

[13] These articles are "Hume's Two Definitions of 'Cause'" by J.A. Robinson; T.J. Richard's "Hume's Two Definitions of 'Cause'" and Robinson's reply to Richards, "Hume's Two Definitions of 'Cause' Reconsidered", all in Hume: A Collection of Critical Essays, ed., V.C. Chappel (Notre Dame Press, 1968).

[14] Livingston, p. 49. We are indebted to Livingston for having marshalled these texts conveniently for our purpose here.

[15] In his Enquiry, Hume renders these definitions as follows: "[Df. 1] Suitable to this experience, therefore, we may define a cause to be an object followed by another, and where all the objects, similar to the first are followed by objects similar to the second. Or, in other words, where, if the first object had not been, the second never had existed." [Df. 2]. We may, therefore, suitably to this experience, form another definition of cause; and call it, an object followed by another, and whose appearance always conveys the thought to that other" (EU 76-7). Between these two, Hume makes a direct reference to the operation of belief: "The appearance of a cause always conveys the mind, by a customary [or "instinctive"] transition, to the idea of the effect. Of this also we have experience". As others note, Hume simplifies and abridges his thought and language in the Enquiries. The articles listed in n.13 debate the logic and equivalence of these definitions. Our concern is strictly to show Hume to mislead here by reducing metaphysical to psychological or belief-constructed causation. Hence also note an unmediated Custom rendered as "customary" above, and elsewhere, and having the sense of psychological instinct.

[16] Moreover, having stated his two definitions of 'cause' in the Enquiry, Hume writes: "But though both these definitions be drawn from circumstances foreign to the cause, we cannot remedy this inconvenience, or attain any more perfect definition, which may point out that circumstance in the cause, which gives it a connexion with its effect. We have no idea of this connexion' nor even any distinct notion what it is we desire to know, when we endeavour at a conception of it" (EU 77).

[17] Of course, 'mind' and 'soul' in Hume are indeed problematic, in as much as he denies the existence of spiritual substance (Treatise, Bk. I, Pt. IV: VI) and material substance (Treatise, Bk. I, Pt. Iv: II). Hence, just how the 'mind' or 'soul' can act is a crucial question, and, as such, beyond our scope here. Livingston attributes the 'force and vivacity' of perceptions to mental acts: "Since force and vivacity is an act of the mind and since some degree of force and vivacity is internal to every perception, it follows that all perceptions are internal to acts of mind" (p. 57). We shall criticize Livingston's claim in Pt. IV.

[18] T.E. Jessop, "Some Misunderstandings of Hume" in V.C. Chappel ( p. 50).

[19] For Hume, the association of present impression with present impression is experience, but not belief. And the association of idea with idea is, if intuitive or demonstrative, reasoning a priori, otherwise memory or arbitrary imagination.

[20] Strictly, Hume's 'first principle' implies as many ideas of x as impressions of x, hence the awkwardness of idea(s) and 'its/their', etc. But, as others note, Hume means by impressions "all our sensations, passions, and emotions" (T1), and hence the same for ideas, except for their force and vivacity. Hence, it is plausible to think of repeated impressions as reinforcing an originally caused idea (e.g., of 'wood-burning') or state of mind. And since Hume simply works with impression(s)-idea, we return to that form.

[21] Anthony Flew, "Private Images and Public Language", in Human Understanding: Studies in the Philosophy of David Hume, ed. Sesonske and Fleming (Wadsworth Publishing, 1965), p. 39. Flew continues mistakenly to claim that the impression-to-idea relation is "open to falsification by the production of a recalcitrant negative instance". We shall briefly discuss Hume's own famous example of the missing shade of blue as not a significant 'negative instance' here.

[22] H.H. Price, "The Permanent Significance of Hume's Philosophy, ibid, p. 7

[23] MacNabb, p. 80. He writes that: "Hume found that all causal inferences from the existence of one object to that of another are nondemonstrative and based on the relations of cause and effect ... An exception to any causal connection is clearly imaginable; so is a pure fluke or a sudden change in the course of nature. Only by experience can we know whether any of these occur".

[24] MacNabb, p. 76. We do not deny that the impression-to-idea relation is "exhaustive" and "cramping", and indeed "dogmatic", these claims being here irrelevant. More to the point, we do deny that the relation is a "dichotomy".

[25] Wayne Waxman, "Impressions and Ideas: Vivacity as Verisimilitude", in Hume Studies, Vol. XIX, No. 1, April 1993, pp. 77-78.

[26] Waxman, p. 77. An earlier article by Saul Traiger entitled "Impressions, Ideas, and Fictions" (Hume Studies, Vol. XIII, No. 2, Nov. 1987, pp. 381-99) refers to "simple and complex ideas which are derived from antecedent and resembling impressions" (p. 395). But Traiger does not really interpret "derived from". Hence, no causal relation appears in his analysis.

[27] Gilbert Ryle, The Concept of Mind (New York, 1949) pp. 249-50.

[28] Barry Stroud, Hume (Routledge: London and New York), 1977. Stroud writes: "If we never get our impression of the necessary connection between cause and effect in any particular instance of causality; it would seem that Hume's main methodological principal must be abandoned. The idea of causality appears to be a counter-example to the principle that all ideas arise in the mind as the result of their corresponding earlier impressions. Hume is aware of the threat this poses, and admits, albeit somewhat disingenuously, that the principle will have to be given up if the impressions from which the idea of causality is derived cannot be found ([T] p. 77). This gives some further evidence that he regards the principle as contingent" (p. 45). At T77 Hume writes: "Shall the despair of success make me assert, that I am here possest of an idea [of "necessary connexion"], which is not preceded by any similar impression? This wou'd be too strong a proof of levity and inconstancy; since the contrary principle has been already so firmly established, as to admit of no farther doubt; at least, till we have more fully examin'd the present difficulty" (later italics added). Hume's concluding caveat refers to the careful and ordered argument by which he reaches the impression grounding the idea of necessary connexion, having shown that contiguity, succession and constant conjunction in experience are necessary but not sufficient for the ascription of causality. Hume never really doubts his methodological principle of original causation, as indeed Stroud's word "disingenuously" shows. We add that Hume's reaching the impression of necessary connexion is hardly evidence that he "regards the principle as contingent".

[29] Livingston, p. 55.

[30] Livingston, p. 57.

[31] This passivity of mind, is especially evident in Hume's moral theory, where Hume reduces "The calm and indolent judgments of the understanding" (T457) to mere auxiliaries of the moral feelings of approval and disapproval really moving us to act, and deriving from universal sympathy. Behind this passivity is, of course, Locke's tabula rasa. Hume presents the passivity of the mind in many different ways and contexts, including his famous ethical claim that "reason is, and ought to be, the slave of the passions". So, again, discussing belief, and hence the original causation producing it, in the Appendix to the Treatise, Hume emphasizes the mind's passivity: "They [ideas believed] strike upon us with more force; they are more present to us, the mind has a firmer hold of them, and is more actuated and mov'd by them. It acquiesces in them; and, in a manner fixes and reposes itself on them" (TA624). This matter of the mind's passivity is currently being debated in Dialogue. Cf. Martin Gerwin's "Natural-Agency Theory as an Alternative to Hume: A Reply to Andrew Ward" (Dialogue, Vol. XXVII, N. 1, 1998) pp. 3-12.

[32] Dissociating causality from original impressions, Livingston writes that what Hume means by impressions "is 'the perceptions themselves' independent of all causal understanding of them. Hume has left entirely open the question of whether perceptions are produced passively in the mind, whether they are produced by the mind, or whether they are independent of the mind"(p. 49). Livingston is right when Hume treats impressions as effects, but quite mistaken to reduce "causal understanding" of them to their being considered effects only: very clearly, now they are original causes of their ideas.

[33] Hume is widely thought to provide an exception or counter-example to this great connexion between impression and idea: that famous, missing shade of blue "which may prove, that "'tis not absolutely impossible for ideas to go before their correspondent impressions" (T5). If we suppose a person to have experienced colours generally, and all shades of blue but one in particular, most will agree that "'tis possible for him, from his own imagination, to supply this deficiency, and raise up to himself the idea of that particular shade, tho' it had never been conveyed to him by his senses ...". Thus, somehow, one can interpolate the idea (or image) of that missing shade of blue without have it caused by an original impression. Now, in denying any real importance to this exception to impression-to-idea, we are assisted first by Hume himself and then by Karann Durland's article, "Hume's First Principle, His Missing Shade and His Distinctions of Reason", Hume Studies, (Vol. XXII, N. 1, Apr. 1966) pp. 105-121. First, Hume himself dismisses "the instance [a]s so particular and singular, that "'tis scarce worth our observing, and does not merit that for it alone we should alter our general maxim" (T6). Next, Durland argues admirably that the missing shade is such that "any new simple idea not (ultimately) derived from a corresponding precedent impression is constructed entirely from elements encountered in precedent simple impressions" (pp. 116-117). Yet this construction is not such as to make the "new simple idea" inconsistently divisible. Rather the imagination, discriminating the content of the impressions as 'distinctions of reason' otherwise inseparable from that context, "runs on" (as Hume puts it) with a kind of inertia, and blends these together to form the idea of the missing shade. But what about Hume's suggesting it possible for such interpolated ideas "to go before their correspondent impressions"? We reply in terms of Hume's distinction between impressions of sense and impressions of reflection: when ideas arising from impressions of sense "produce the images of themselves" they produced and "go before" impressions of reflection, such as would happen here with the interpolated idea of the shade of blue. Thus Hume is not here inconsistent as we interpret him, since "as the first ideas [here, that of the blue-shade] are supposed to be derived [here, by construction] from impressions [of sense], it still remains true, that all our simple ideas proceed either mediately or immediately from their correspondent impressions" (T7). In summation, then, the simple idea of the missing blue-shade proceeds mediately, and by construction, from sense impressions of other blue-shades, producing in turn its own impression of reflection, that of the missing shade of blue.

[34] John W. Carroll, "Human Justified Belief", The Philosophical Quarterly, Vol. 40, N. 192, July 1998, pp. 373-378.

[35] T. Beauchamp, and A. Rosenberg, Hume and the Problem of Causation, Oxford: Oxford University Press, 1981.

[36] M. Costa, "Hume and Justified Belief", Canadian Journal of Philosophy, V. 11, 1981, pp. 219-228.

[37] Carroll, p. 375.

[38] Carroll, p. 375.

[39] Wilson's massive study follows the positivism of Ayer and others cited throughout: he does not consider the impression-to-idea relation as such, and neither term appears in his index. Nor do the terms 'Custom', 'metaphysics' or even 'belief' appear there. Wilson does quote Hume: "There is a NECESSARY CONNEXION to be taken into consideration; and that relation is of much greater importance than any of the other two above mention'd' (Ti.III.ii, T7)." But Wilson treats necessary connexion very briefly, reducing it to the psychology of belief-constructed causation and citing Hume's second definition of cause at that level as "An object precedent and contiguous to another, and so united with it in the imagination, that the idea of the one determines the mind to form the idea of the other, and the impression of the one to form a more lively idea of the other' (T172)" (p. 16). He concludes here that "The idea of necessary connexion, which is an ingredient in the idea of cause, is therefore, the propensity of the mind to make inferences in the case of causal connections which is absent in the case of accidental generalities(T167)". Wilson's note 26 here simply recalls, in this context, the difference between constant conjunction as inadequate, and necessary connection as adequate, for "The assertion of causal ... generalities" (p. 371). But what is "the idea of cause" for him? Wilson tells us that "the idea of 'cause' is really two abstract ideas, one of a natural relation, one of a philosophical relation. Now, for Hume, an abstract idea is a resemblance class of ideas and impressions with which a general term has been associated (T20)." Here Wilson mistakenly reduces all causality in Hume to classes of ideas and impressions, when, in fact, causality is about power in Hume, especially in the relation (impression-to-idea) generating belief and hence belief-constructed 'causality'. Moreover, Wilson seriously misunderstands abstraction in Hume. Very briefly, and following Berkeley, Hume asserts abstraction as the relation of a particular idea, signified by a term, to a host of other individual ideas summoned by belief, as we illustrate by the river and triangle examples above: "A very material question has been stated concerning abstract or general ideas, whether they be general or particular in the mind's conception of them. A great philosopher, [Berkeley], has disputed the receiv'd opinion in this particular, and has asserted, that all general ideas are nothing but particular ones, annexed to a certain term, which gives them a more extensive signification and makes them recall upon occasion other individuals, which are similar to them. As I look upon this to be one of the greatest and most valuable discoveries that has been made ... I shall here endeavour to confirm it by some arguments, which I hope will put it beyond all doubt and controversy" (T 17). All of these other individuals are present "in power" such that we "keep ourselves in a readiness to survey any of them, as we may be prompted by a present design or necessity" (T 20). Here, Hume's dynamism in presenting abstraction as a most powerful and belief-founded method, is obvious.

[40] Spinoza, in a doctrine which we cannot pursue here, founds philosophical or deductive method on adequate and true ideas of which the mind, within the divine intellect, is the full or 'adequate' cause. Cf. V. Maxwell: "The Philosophical Method of Spinoza", Dialogue, XVIII (1988) pp. 89-110, for this. Now, while the 'mind' is problematic in Hume, the causal relation of impression-to-idea as it generates belief is closely analogous to the mind's conceiving adequate and true ideas in Spinoza's conception of method. And, the causal relation of impression-to-idea in Hume's doctrine of original causation clearly grounds his method of verifying true ideas through their meaning. To that resonance, we add this: (Custom)-to-(original causation)-to- (belief-constructed causality) can be seen as standing in relation to Spinoza's three levels of knowledge: (scientia intuitiva) - (ratio) - (imaginatio), but with this difference: Spinoza's monism yields an explicit continuity of these levels of causal knowledge. But Hume's atomistic pluralism renders a continuity of his three levels of causality implicit in their mediation, original causation. However, as Hume would say, we insinuate all of this, but without insisting on the matter.

[41] D. Moses, "Hume's Playful Metaphysics", Hume Studies, Vol. XVIII, N. 1, April 1992, pp. 63-79.