A Treatise of Human Nature · David Hume
GENERAL INTRODUCTION TO VOL. I.
300. As to relations in time and space, we have already traced out the inconsistencies which attend Hume’s attempt to represent them as compound ideas. The statement at the beginning of Part III., that they are relations not dependent on the nature of compared ideas, is itself a confession that such representation is erroneous. If the difficulty about the synthesis of successive feelings in a consciousness that consists merely of the succession could be overcome, we might admit that the putting together of ideas might constitute such an idea of relation as depends on the nature of the combined ideas. But no combination of ideas can yield a relation which remains the same while the ideas change, and changes while they remain the same. Thus, when Hume tells us that ‘in none of the observations we may make concerning relations of time and place can the mind go beyond what is immediately present to the senses, to discover the relations of objects’ [1] the statement contradicts itself. Either we can make no observation concerning relation in time and place at all, or in making it we already ‘go beyond what is immediately present to the senses,’ since we observe what is neither a feeling nor several feelings put together.
If then Hume had succeeded in his reduction of reasoning from cause or effect to observation of this kind, as modified in a certain way by habit, the purpose for which the reduction is attempted would not have been attained. The separation between perception and inference, between ‘intuition’ and ‘discourse,’ would have been got rid of, but inference and discourse would not therefore have been brought nearer to the mere succession of feelings, for the separation between feeling and perception would remain complete; and that being so, the question would inevitably recur--If the ‘observation’ of objects as related in space and time already involves a transition from the felt to the unfelt, what greater difficulty is there about the interpretation of a feeling as a change to be accounted for (which is what is meant by inference to a cause), that we should do violence to the sciences by reducing it to repeated observation lest it should seem that in it we ‘go beyond’ present feeling? [1] P. 376. [Book I, part III., sec. II.] As also does the ‘observation concerning identity,’ which the comparison involves.
301. Relation in the way of identity is treated by Hume in the third part of the Treatise [1] pretty much as he treats contiguity and distance. He admits that it does not depend on the nature of any ideas so related--in other words, that it is not constituted by feelings as they would be for a merely feeling consciousness--yet he denies that the mind ‘in any observations we may make concerning it’ can go beyond what is immediately present to the senses. Directly afterwards, however, we find that there _is_ a judgment of identity which involves a ‘conclusion beyond the impressions of our senses’--the judgment, namely, that an object of which the perception is interrupted continues individually the same notwithstanding the interruption. Such a judgment, we are told, is a supposition founded only on the connection of cause and effect. How any ‘observation concerning identity’ can be made without it is not there explained, and, pending such explanation, observations concerning identity are freely taken for granted as elements given by sense in the experience from which the judgment of cause and effect is derived. In the second chapter of Part IV., however, where ‘belief in an external world’ first comes to be explicitly discussed by Hume, we find that ‘propensities to feign’ are as necessary to account for the judgment of identity as for that of necessary connection. If that chapter had preceded, instead of following, the theory of cause and effect as given in Part III., the latter would have seemed much less plain sailing than to most readers it has done. It is probably because nothing corresponding to it appears in that later redaction of his theory by which Hume sought popular acceptance, that the true suggestiveness of his speculation was ignored, and the scepticism, which awakened Kant, reduced to the commonplaces of inductive logic. To examine its purport is the next step to be taken in the process of testing the possibility of a ‘natural history’ of knowledge. Its bearing on the doctrine of cause will appear as we proceed.
Before Theism could be exhibited with the necessity which Locke claimed for it, it was requisite to try what could be done with association of ideas and ‘propensities to feign’ in the way of accounting for the world of knowledge, in order that upon their failure another point of departure than Locke’s might be found necessary. The experiment was made by Hume. He has the merit, to begin with, of stating the nature of identity with a precision which we found wanting in Locke. ‘In that proposition, _an object is the same with itself_, if the idea expressed by the word _object_ were no ways distinguished from that meant by _itself_, we really should mean nothing.’ ‘On the other hand, a multiplicity of objects can never convey the idea of identity, however resembling they may be supposed. ... Since then both number and unity are incompatible with the relation of identity, it must lie in something that is neither of them. But at first sight this seems impossible.’ The explanation is that when ‘we say that an object is the same with itself, we mean that the object existent at one time is the same with itself existent at another. By this means we make a difference betwixt the idea meant by the word _object_ and that meant by _itself_ without going the length of number, and at the same time without restraining ourselves to a strict and absolute unity.’ In other words, identity means the unity of a thing through a multiplicity of times; or, as Hume puts it, ‘the invariableness and uninterruptedness of any object through a supposed variation of time’. [1]
That the existence of an object, which we call the same with itself, is broken by as many intervals of time as there are successive and different, however resembling, ‘perceptions,’ must be the fact; that it should yet be one throughout the intervals is a fiction to be accounted for, Hume accounts for it by supposing that when the separate ‘perceptions’ have a strong ‘natural relation’ to each other in the way of resemblance, the transition from one to the other is so ‘smooth and easy’ that we are apt to take it for the ‘same disposition of mind with which we consider one constant and uninterrupted perception;’ and that, as a consequence of this mistake, we make the further one of taking the successive resembling perceptions for an identical, _i.e._ uninterrupted as well as invariable object. [2] But we cannot mistake one object for another unless we have an idea of that other object. If then we ‘mistake the succession of our interrupted perceptions for an identical object,’ it follows that we have an idea of such an object--of a thing one with itself throughout the succession of impressions--an idea which can be a copy neither of any one of the impressions nor, even if successive impressions could put themselves together, of all so put together.
Such an idea being according to Hume’s principles impossible, the appearance of our having it was the fiction he had to account for; and he accounts for it, as we find, by a ‘habit of mind’ which already presupposes it. His procedure here is just the same as in dealing with the idea of vacuum. In that case, as we saw, having to account for the appearance of there being the impossible idea of pure space, he does so by showing, that having ‘an idea of distance not filled with any coloured or tangible object,’ we mistake this for an idea of extension, and hence suppose that the latter may be invisible and intangible. He thus admits an idea, virtually the same with the one excluded, as the source of the ‘tendency to suppose’ which is to replace the excluded idea. So in his account of identity. Either the habit, in virtue of which we convert resembling perceptions into an identical object, is what Hume admits to be a contradiction, ‘a habit acquired by what was never present to the mind’; [3] or the idea of identity must be present to the mind in order to render the habit possible. [1] ‘Wherever we have no successive perceptions, we have no notion of time.’ (p. 342) [Book I, part II., sec. III.].
305. Thus without professedly admitting into consciousness anything but the succession of feelings he gets such individual objects as Locke would have called objects of ‘actual present sensation.’ When ‘I survey the furniture of my chamber,’ according to him, I see sundry ‘identical objects’--this chair, this table, this inkstand, &c. [1] So far there is no fiction to be accounted for. It is only when, having left my chamber for an interval and returned to it, I suppose the objects which I see to be identical with those I saw before, that the ‘propensity to feign’ comes into play, which has to be explained as above. But in fact the original ‘survey’ during which, seeing the objects, I suppose them to continue the same with themselves, involves precisely the same fiction. In that case, says Hume, I ‘suppose the change’ (which is necessary to constitute the idea of identity) ‘to lie only in the time.’ But without ‘succession of perceptions,’ different however resembling, there could according to him be no change of time. The continuous survey of this table, or this chair, then, involves the notion of its remaining the same with itself throughout a succession of different perceptions--_i.e._ the full-grown fiction of identity--just as much as does the supposition that the table I see now is identical with the one I saw before. The ‘reality,’ confusion with which of ‘a smooth passage along resembling ideas’ is supposed to constitute the ‘fiction,’ is already itself the fiction--the fiction of an object which must be other than our feelings, since it is permanent while they are successive, yet so related to them that in virtue of reference to it, instead of being merely different from each other, they become changes of a thing.
The question is how the propension can be satisfied by a supposition which is merely another expression for one of the contradictory beliefs. What difference is there between the appearance of a perception and its existence, that interruption of the perception, though incompatible with uninterruptedness in its appearance, should not be so with uninterruptedness in its existence? It may be answered that there is just the difference between relation to a feeling subject and relation to a thinking one--between relation to a consciousness which is in time, or successive, and relation to a thinking subject which, not being itself in time, is the source of that determination by permanent conditions, which is what is meant by the real existence of a perceived thing. But to Hume, who expressly excludes such a subject--with whom ‘it exists’ = ‘it is felt’--such an answer is inadmissible. He can, in fact, only meet the difficulty by supposing the existence of unfelt feelings, of unperceived perceptions. The appearance of a perception is its presence to ‘what we call a mind,’ which ‘is nothing but a heap or collection of different perceptions, united together by certain relations, and supposed, though falsely, to be endowed with a perfect simplicity and identity’.
307. It is implied, then, in the process by which, according to Hume, the fiction of a continued being is arrived at, that this being is supposed to be not only continued but ‘distinct from the mind’ and ‘independent’ of it. With Hume, however, the supposition of a distinct and ‘independent’ existence of the _perception_ is quite different from that of a distinct and independent object other than the perception. The former is the ‘vulgar hypothesis,’ and though a fiction, it is also a universal belief: the latter is the ‘philosophical hypothesis,’ which, if it has a tendency to obtain belief at all, at any rate derives that tendency, in other words ‘acquires all its influence over the imagination,’ from the vulgar one. [1] Just as the belief in the independent and continued existence of perceptions results from an instinctive effort to escape the uneasiness, caused by the contradiction between the interruption of resembling perceptions and their imagined identity, so the contradiction between this belief and the evident dependence of all perceptions ‘on our organs and the disposition of our nerves and animal spirits’ leads to the doctrine of representative ideas or ‘the double existence of perceptions and objects.’ ‘This philosophical system, therefore, is the monstrous offspring of two principles which are contrary to each other, which are both at once embraced by the mind and which are unable mutually to destroy each other. The imagination tells us that our resembling perceptions have a continued and uninterrupted existence, and are not annihilated by their absence. Reflection tells us that even our resembling perceptions are interrupted in their existence and different from each other. The contradiction betwixt these opinions we elude by a new fiction which is conformable to the hypotheses both of reflection and fancy, by ascribing these contrary qualities to different existences; the interruption to _perceptions_, and the continuance to _objects_’. [2]
Are they not all involved in the simplest perception? 309. That it is gratuitous we may readily admit, but only because a recognition of the function of the Ego in the primary constitution of the qualified individual object--this pen or this paper--renders it superfluous. To the philosophy, however, in which Hume was bred, the perception of a qualified object was simply a feeling. No intellectual synthesis of successive feelings was recognized as involved in it. It was only so far as the dependence of the feeling on our organs, in the absence of any clear distinction between feeling and felt thing, seemed to imply a dependent and broken existence of the thing, that any difficulty arose--a difficulty met by the supposition that the felt thing, whose existence was thus broken and dependent, represented an unfelt and permanent thing of which it is a copy or effect. To the Berkeleian objections, already fatal to this supposition, Hume has his own to add, viz. that we can have no idea of relation in the way of cause and effect except as between objects which we have observed, and therefore can have no idea of it as existing between a perception and an object of which we can only say that it is not a perception. Is all existence then ‘broken and dependent’?
That is the ‘sceptical’ conclusion which Hume professes to adopt--subject, however, to the condition of accounting for the contrary supposition (without which, as he has to admit, we could not think or speak, and which alone gives a meaning to his own phraseology about impressions and ideas) as a fiction of the imagination. He does this, as we have seen, by tracing a series of contradictions, with corresponding hypotheses invented, either instinctively or upon reflection, in order to escape the uneasiness which they cause, all ultimately due to our mistaking similar successive feelings for an identical object. Of such an object, then, we must have an idea to begin with, and it is an object permanent throughout a variation of time, which means a succession of feelings; in other words, it is a felt thing, as distinct from feelings but to which feelings are referred as its qualities. Thus the most primary perception--that in default of which Hume would have no reality to oppose to fiction, nor any point of departure for the supposed construction of fictions--already implies that transformation of feelings into changing relations of a thing which, preventing any incompatibility between the perpetual brokenness of the feeling and the permanence of the thing, ‘eludes’ by anticipation all the contradictions which, according to Hume, we only ‘elude’ by speaking as if we had ideas that we have not.
Yet they are not possible ideas, because copied from no impressions. 310. ‘Ideas that we _have not_;’ for no one of the fictions by which we elude the contradictions, nor indeed any one of the contradictory judgments themselves, can be taken to represent an ‘idea’ according to Hume’s account of ideas. He allows himself indeed to speak of our having ideas of identical objects, such as _this table while I see or touch it_--though in this case, as has been shown, either the object is not identical or the idea of it cannot be copied from an impression--and of our transferring this idea to resembling but interrupted perceptions. But the supposition to which the contradiction involved in this transference gives rise--the supposition that the perception continues to exist when it is not perceived--is shown by the very statement of it to be no possible copy of an impression. Yet according to Hume it is a ‘belief,’ and a belief is ‘a lively idea associated with a present impression.’ What then is the impression and what the associated idea? ‘As the propensity to feign the continued existence of sensible objects arises from some lively impressions of the memory, it bestows a vivacity on that fiction; or, in other words, makes us believe the continued existence of body’. [1] Well and good: but this only answers the first part of our question. It tells us what are the impressions in the supposed case of belief, but not what is the associated idea to which their liveliness is communicated. To say that it arises from a propensity to feign, strong in proportion to the liveliness of the supposed impressions of memory, does not tell us of what impression it is a copy. Such a propensity indeed would be an ‘impression of reflection,’ but the fiction itself is neither the propensity nor a copy of it. The only possible supposition left for Hume would be that it is a ‘compound idea;’ but what combination of ‘perceptions’ can amount to the existence of perceptions when they are not perceived?
Now it is clear that though the recognition takes place upon occasion of a feeling, the object recognized--this flame or this heat--is by no means the feeling as a ‘perishing existence.’ Unless the feeling were taken to represent a thing, conceived as permanently existing under certain relations and attributes--in other words, unless it were _identified_ by thought--it would be no definite object, not this _flame_ or this _heat_, at all. The moment it is named, it has ceased to be a feeling and become a felt thing, or, in Hume’s language, an ‘individual of _a species of objects_.’ And just as the present ‘perception’ is the recognition of such an individual, so the remembrance which determines the recognition is one wholly different from the return with lessened liveliness of a feeling more strongly felt before. According to Hume’s own statement, it consists in recalling ‘frequent instances of the existence of _a species of objects_.’ It is remembrance of an experience in which every feeling, that has been attended to, has been interpreted as a fresh appearance of some qualified object that ‘exists’ throughout its appearances--an experience which for that reason forms a connected whole.
If it were not so, there could be no such comparison of the relations in which two objects are now presented with those in which they have always been presented, as that which according to Hume determines us to regard them as cause and effect. The condition of our so regarding them is that we suppose the objects now presented to be _the same_ with those of which we have had previous experience. It is only on supposition that a certain sensation of sight is not merely like a multitude of others, but represents the same object as that which I have previously known as flame, that I infer the sequence of heat and, when it does follow, regard it as an effect. If I thought that the sensation of sight, however like those previously referred to flame, did not represent the same object, I should not infer heat as effect; and conversely, if, having identified the sensation of sight as representative of flame, I found that the inferred heat was not actually felt, I should judge that I was mistaken in the identification. It follows that it is only an experience of identical, and by consequence related and qualified, objects, of which the memory can so determine a sequence of feelings as to constitute it an experience of cause and effect. Thus the perception and remembrance upon which, according to Hume, we judge one object to be the cause of another, alike rest on the ‘fictions of identity and continued existence.’ Without these no present experience would, in his language, be an instance of an individual of a certain species existing in a certain relation, nor would there be a past experience of individuals of the same species, by comparison with which the constancy of the relation might be ascertained.
Now undoubtedly if the identity of interrupted perceptions is one fiction of the imagination and the relation of cause and effect another, each resulting from ‘custom,’ to say with Hume, that we must have the idea of cause in order to arrive at the supposition of identity, is logically to exclude any derivation of that idea from an experience which involves the supposition of identity. The ‘custom’ which generates the idea of cause must have done its work before that which generates the supposition of identity can begin. Hume therefore, after the admission just quoted, was not entitled to treat the inference to cause or effect as a habit derived from experience of identical things. But it is otherwise if the conceptions of causation and identity are correlative--not results of experience of which one must be formed before the other, but co-ordinate expressions of one and the same synthetic principle, which renders experience possible. And this is the real state of the case. It is true, as Hume points out, that when we want to know whether a certain sensation, precisely resembling one that we have previously experienced, represents the same object, we do so by asking how otherwise it can be accounted for.
If no difference appears in its antecedents or sequents, we identify it--refer it to the same thing--as that previously experienced; for its relations (which, since it is an event in time, take the form of antecedence and sequence) _are_ the thing. The conceptions of identity and of relation in the way of cause and effect are thus as strictly correlative and inseparable as those of the thing and of its relations. Without the conception of identity experience would want a centre, without that of cause and effect it would want a circumference. Without the supposition of objects which ‘existing at one time are the same with themselves as existing at other times’--a supposition which at last, when through acquaintance with the endlessness of orderly change we have learnt that there is but one object for which such identity can be claimed without qualification, becomes the conception of nature as a uniform whole--there could be no such comparison of the relations in which an object is now presented with those in which it has been before presented, as determines us to reckon it the cause or effect of another; but it is equally true that it is only by such comparison of relations that the identity of any particular object can be ascertained. [1] P. 376. [Book I, part III., sec. II.]
Hume quite right in saying that we do not go _more_ beyond sense in reasoning than in perception. 314. Thus, though we may concede to Hume that neither in the inference to the relation of cause and effect nor in the conclusions we draw from it do we go ‘beyond experience,’ [1] this will merely be, if his account of it as a ‘philosophical relation’ be true, because in experience we already go beyond sense. ‘There is nothing,’ says Hume, ‘in any object considered in itself that can afford us a reason for drawing a conclusion beyond it’ [2]--a statement which to him means that, if the mind really passes from it to another, this is only because as a matter of fact another feeling follows on the first. But, in truth, if each feeling were merely ‘considered in itself,’ the fact that one follows on another would be no fact _for the subject of the feelings_, no starting-point of intelligent experience at all; for the fact is the relation between the feelings--a relation which only exists for a subject that considers neither feeling ‘in itself,’ as a ‘separate and perishing existence,’ but finds a reality in the determination of each by the other which, as it is not either or both of them, so survives, while they pass, as a permanent factor of experience.
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