why hume is a direct realist

Why Hume is a Direct Realist*

by Cass Wel ler (Seattle)

All the perceptions of the human mind resolve themselves into two distinct kinds,which I shall call impressions and ideas. The difference betwixt these consists inthe degrees of force and liveliness, with which they strike upon the mind, andmake their way into our thought or consciousness. Those perceptions which enterwith most force and violence, we may name impressions; and, under this name,I comprehend all our sensations, passions, and emotions, as they make their firstappearance in the soul. [T. 1]

It is natural enough, or at least it has been customary, to read this opening passageof the Treatise as follows. Force and vivacity are nothing more than introspectibleoccurrent features of mental acts or their contents which distinguish impressionsfrom ideas. This is one obvious way of making sense of Hume’s subsequent empiricalargument that ideas are caused by the impressions they resemble. For if, on thecontrary, the force and vivacity of an impression were to be antecedently understoodin terms of the causal powers of a mental act to produce an idea there would notseem much point in using the experimental method of reasoning as a method ofdiscovery to establish that impressions cause ideas. Moreover, the faintness in termsof which ideas are often contrasted with impressions suggests that the contrastingfeature of force and vivacity has to do with vividness of content rather than causalfeatures of impressions as mental acts.1

* I thank Kate Abramson, Charles Marks, Ken Winkler, and this journal’s review-ers for helpful comments on an earlier version of this paper.

1 This certainly seems to be Hume’s position in the first Enquiry. See section 2,para. 17, for example. The Treatise itself also provides occasion for this view.“ ‘Tis evident at first sight, that the ideas of memory are much more lively andstrong than those of the imagination, and that the former faculty paints its ob-jects in more distinct colors, than any which are employ’d by the latter.” [T. 9]For a fairly recent repetition of the idea that force and vivacity pertain to theintrinsic character of content see Elijah Millgram (“Was Hume a Humean?”,Hume Studies, Vol. XXI, No. 1, 1995, p. 82). More typical is the view that thegreater degree of force and vivacity distinguishing an impression from its corre-sponding idea consists in the fact that the impression calls greater attention toitself. Here the leading phrase is “strikes upon the mind”. Barry Stroud (Hume,London: Routledge and Kegan Paul, 1977, pp. 28 f.), for example, seems to takethis view. One can distinguish two versions of this view depending on what it isthat is calling attention to itself. (1) A perception, x, is more forceful than aperception, y, because the perceiver pays more attention to what x represents

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259Why Hume is a Direct Realist

I challenge this view of impressions and ideas. Moreover, from the standpoint ofthe alternative I am about to develop the most backward inference to draw fromthe fact that Hume links belief to the force and vivacity of impressions of (outer)sense (hereafter impressions of sense unless otherwise noted) would be the following.Since (1) judgment, assent, and belief are nothing but the force and vivacity (immedi-ate or inherited) of an impression, (2) force and vivacity are either ingredient featuresof content or merely phenomenal features of perceptions as mental acts, and (3)impressions have no propositional content anyway, Hume has no theory of belief.2

I claim that (2) and (3) are falsely attributed to Hume. I claim instead, in the natural-ist tradition of interpretation, that in Hume the force and vivacity of an impressionof sense is (i) its assertoric or doxastic character, (ii) the power to transmit thisassertoric or doxastic character through inference, (iii) the power to produce pas-sions3 against a background of beliefs and affective propensities.4 I develop a defense

than to what y represents. (2) A perception, x, is more forceful than a perception,y, because the perceiver pays more attention to x as a mental act, irrespective ofits content, than to y as a mental act, irrespective of its content. S’s visual experi-ence of a pinkish-orange sunset is more forceful than some other visual experi-ence because she pays more attention to the former than to the latter as a visualexperiencing. Version (2) has the curious virtue of providing Hume with a uni-form and one-dimensional account of force and vivacity as it applies to any pairof perceptions. For example, S’s being in pain calls greater attention to itselfthan S’s thought containing the idea of pain, even S’s thought about that pain.

2 Stroud (1977, p. 72) does not construe force cum vivacity as an intrinsic featureof content. In fact he provides, parallel to T. 96, a compelling argument againstit. Two ideas can differ in force and vivacity, although they are ideas with iden-tical content. Therefore, the force and vivacity of an idea does not pertain to thecontent of an idea. David Pears (Hume’s System, New York: Oxford UniversityPress, 1990, pp. 48 f.) similarly argues against construing the liveliness of an ideaas a pictorial property. He thinks Hume’s account of belief fails, however, bothbecause the account is phenomenological and reductive (p. 52) and becauseHume’s theory neglects the propositional structure of ideas as truth bearers(p. 55). Stroud (1977, p. 74), rather ironically from my point of view, thinks thatthe failure of Hume’s account of belief is due in part to Hume’s neglect of thevery connection between belief and the passions and the will that Hume indicateswhen he speaks of belief-constituting force and vivacity as what “renders [ideasof the judgment] the government principles of all our actions”. [T. 629]

3 This is not the occasion to take up the important and difficult task of systemati-cally sorting out the various and multidimensional relations among beliefs (in-cluding impressions of (outer) sense), moral sentiments, and other impressionsof reflection.

4 The interpretation I defend overlaps with that of Stephen Everson (“The Dif-ference between Feeling and Thinking”, Mind vol. XCVII, no. 387, July 1988,pp. 4012413). He takes force and vivacity to be functional/causal notions andemphasizes the action-actuating character of beliefs and impressions. However,he takes Hume to be operating under the constraints of thoroughgoing solipsism.On his view, I take it, Hume is generally barred from distinguishing an impres-sion of sense from a forceful copy of it by appealing to the fact that the objectand its properties are causally present to the perceiver in the case of an impres-



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of the first two points after which I will argue that an impression of sense differsfrom an idea that copies it by involving the causal presence of the object. If success-ful in these phases of my argument I will have made a preliminary case for the claimthat for Hume an impression of (outer) sense is a robust noninferentially producedperceiving of an object in the environment causally wrung from a perceiver by theobject, and thus that Hume is, to that extent, a direct realist.

In the course of my argument I shall have to deal with the notorious passageswhere Hume seems to give encouragement to those who would see him as either anhonest methodological solipsist operating behind the veil of perception or a skepticpoised to strike. In particular, I provide a diagnosis of the skeptical import of I.iv.2.It is, of course, the interpretive assumption of epistemological purity that is thesource of what, from my standpoint, is the mistaken view about impressions andideas. Those who subscribe to this view of Hume’s framework will note that he

sion. Where Hume appears to do this or generally speak of the senses as causallyaffected by material objects, we must make apologies or explain it away. WhatI find puzzling in this is that Everson does not see this as applying to the forceand vivacity of impressions of reflection. If their force and vivacity is the causal-ity of passions as springs of action then one has already lifted the veil of per-ception. The active causality of passions and the passive causality of impressionsof sense are perfectly coordinate. Bodies are causally reflected in the perceptualjudgments they engender in sentient bodies; the passions of sentient bodies arereflected in the actions of sentient bodies upon the objects of perceptual judg-ments. This is obviously not the occasion to try and settle the question ofwhether Hume’s naturalism and presumed methodological solipsism are coordi-nate or the one is subordinated to the other. It is a complicated question. Ever-son’s stance is to see how far one can go in overturning the traditional interpreta-tion of force and vivacity with Hume still yoked to the methodological solipsismtraditionally ascribed to him even by those who regard themselves as workingwithin the naturalist tradition of interpretation. I put Hume under no such con-straints. Instead, since I regard his unfettered naturalist account of causal infer-ence to be central to the project of Book I of the Treatise, it is the apparentsolipsism that must be shaped to fit or explained away. After all, the subtitle ofthe book is “an attempt to introduce the experimental method of reasoning intomoral subjects” not “the solipsistic method ”.

Of course, there is nothing novel in challenging the interpretation of Humeas a take-no-prisoners skeptic. Norman Kemp Smith (The Philosophy of DavidHume, London: Macmillan, 1941) is usually mentioned as having inaugurated anaturalist reading of Hume in the twentieth century. More recently Stroud (1977,p. xi, cf. pp. 1216) describes his reading as continuous with the Kemp Smithtradition of interpreting Hume as a philosophical naturalist. More recent effortsin this tradition are Don Garrett’s Cognition and Commitment in Hume’s Philoso-phy (New York: Oxford University Press, 1997) and Annette Baier’s A Progressof the Sentiments (Cambridge: Harvard University Press, 1991). It is from Baier’sbook that I have in all likelihood borrowed in ways I cannot keep track of. Thekind of naturalist reading I am advocating is rather extreme. I am supposingthat Hume’s science of man is a science of minded human bodies embedded ina world of minded and unminded bodies.




cannot consistently distinguish an idea of sense from an impression of sense byappealing to external facts such as the fact that an impression of a red sphere in-volves the presence of a red sphere in the environment of the perceiver, whereas anidea of a red sphere does not. Where he appears thus to appeal to external facts onewho is committed to reading Hume as epistemologically pure will simply shrug inirritation and puzzlement at the lapse from official policy.5

I

To establish that the force and vivacity of an impression of sense isprimarily its assertoric character and power to transmit assertoric char-acter I turn to a passage at Treatise I.iii.5. Here Hume collects memoryand sense as faculties providing the anchors and starting points ofcausal inference and contrasts them with imagination.

Thus it appears, that the belief or assent, which always attends the memory andsenses, is nothing but the vivacity of those perceptions they present; and that thisalone distinguishes them from the imagination. To believe is in this case to feelan immediate impression of the senses, or a repetition of that impression in thememory. It is merely the force and liveliness of the perception, which constitutesthe first act of the judgment, and lays the foundation of that reasoning, whichwe build upon it, when we trace the relation of cause and effect. [T. 86]

Earlier, in the previous section, Hume had argued that without self-standing premises from memory or sense a chain of reasoning aboutsome matter of fact would remain merely hypothetical. No conclusionwould be detached from such a chain of conditionals as a claim on itsown unless there were a prior claim from sense or memory to start theprocess of detachment.6 Here, in the concluding paragraph of I.iii.5,Hume makes it as clear as possible that acts of memory and senseprovide premises for what would otherwise remain merely hypotheticalreasoning about matters of fact. It is the force and vivacity of theseacts of sense and memory that constitute them as acts of judgementwith assertoric character. Hume explicitly characterizes impressions ofsense as acts of judgements and ties this to their force and vivacity.

5 For related reasons having to do with presumed Humean skepticism about causa-tion and bodies it would be similarly inappropriate, on this view, for force and vi-vacity to be used to characterize impressions in terms of their causal powers, es-pecially as links in a chain of causes of action involving bodies. And thus it isconvenient for this view to ignore the fact that the force and vivacity of some im-pressions of reflection is precisely the motive power of self-moving sentient bodies.

6 Hume reiterates this point in I.iii.6 in the course of explaining his definition ofbelief. [T. 97]



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Perfect ideas of the imagination, we are told [T. 8], copy impressionsof sense, yet have lost entirely the vivacity of the impressions they copy.Hume says this marks a species of ideas distinct from that of the pro-ducts of memory. In our passage at I.iii.5 he picks up the point, aspromised in I.i.3, and connects the force and vivacity, which is absentfrom (perfect) ideas of the imagination, with the assertoric characterand inference-initiating power of impressions of sense and memory.Mere ideas of the imagination may be causally efficacious in introduc-ing other ideas through other associative mechanisms, but these latterideas are not beliefs, except accidentally. Indeed, throughout Part IIIand the accompanying material in the appendix7 Hume repeatedlymakes the point that the assent marking a belief off from a mere ideais the force and vivacity of the former. And although Hume seemsgenerally to prefer to use the term ‘belief’ for enlivened ideas 2 theofficial definition of belief at I.iii.7 classifies it as “a lively idea relatedto or associated with a present impression” 2 the point stands: what-ever assertoric character an idea of sense has that makes it a belief isinherited from an impression of sense or memory. It is this idea ofinherited assertoric character that plays a critical role in Hume’s ac-count of reasoning from the observed to the unobserved. An impres-sion of sense together with experience of constant conjunction not onlycauses an idea of what usually attends the object of the impression; theimpression, by transmitting its force and vivacity to the idea it inferen-tially produces, causes that idea to be a belief.

A present impression, then, is absolutely requisite to this whole operation; andwhen after this I compare an impression with an idea, and find that their onlydifference consists in their different degrees of force and vivacity, I conclude uponthe whole, that belief is a more vivid and intense conception of an idea, proceed-ing from its relation to a present impression. [T. 103]

Hume emphasizes over and over again that the force and vivacity thatmark an idea as a belief pertain to the manner of conceiving ratherthan to what is conceived. I take this as a central piece of evidenceagainst the claim that force and vivacity are qualities of pictorial

7 Although Hume speaks of the force and vivacity that defines belief as an intro-spectible feeling or manner of conceiving, what one feels beyond the narrowfeeling of assent is the dynamic character of these mental acts to influence thepassions and imagination which I take to include the power to produce othercognitive acts, various impressions of reflection, and ultimately action. [SeeT. 629]




content or the like.8 Now one might, I suppose, try to drive a wedgebetween forcefulness as the manner of conceiving and assent as whatit compels. One would thus let force and vivacity play a role analogousto clarity and distinctness in Meditation IV as compelling assent. Butthere is no comparable faculty of intellectual volition in Hume.

Indeed this is the point I think he is making, however obliquely,throughout his discussion of belief in the context of causal inference.9

In a typically Humean move he is reversing a familiar explanatorypriority, in this case that of conception and assertion.10 Impressions ofsense do not merely present a phenomenal scene to be assented to bysome further faculty. To have an impression of a red sphere over thereis not simply to entertain the content ‘red sphere over there’, but ratherto perceive the red sphere over there as a red sphere over there or tojudge perceptually that there is a red sphere over there.

Clearly, if inference is from an assertoric truth-valued-representingto an assertoric truth-valued-representing and causal inference is fromimpression to idea, then impressions of sense and their inferentiallyproduced ideas are assertoric truth-valued-representings. I think thatthe flexibility in Hume’s use of ‘impression’ in, say, ‘an impression ofthat green tree’ and ‘an impression that that tree is green’ reflects theflexibility of ‘perceives’ and the specific verbs of perceiving and not aradical ambiguity between brute sensory awareness and concept-borne

8 One might be tempted, especially in light of T. 9 and T. 96 where Hume appearsto link liveliness to distinctness of color and brightness respectively, to think thatforce and vivacity generally distinguish impressions of (outer) sense from ideasin virtue of greater detail and determinateness of content. This is mistaken,though. As already noted (n. 2) Hume commits himself at T. 96 to the claim thattwo ideas identical in content may differ in force and vivacity. Moreover, it iscentral to Hume’s account of abstract ideas that the content of every idea isintrinsically determinate. An abstract idea is, paradoxically, particular in its na-ture while general in its representation. [T. 17224]

9 Even where he speaks of belief as something joined to conception it is in thecontext of his proposing his hypothesis that belief is “only a strong and steadyconception of any idea, and as such approaches in measure to an immediateimpression”. [T. 96 f. fn.]

10 This reversal of explanatory priority is typical of Hume’s general anti-intellectua-list strategy throughout I.iii. Causal inference, to take the obvious example, isnot explained in terms of grasping a necessary connection between premise andconclusion. The idea of necessary connection is explained as a product of causalinference. Moreover, while causal inference presupposes the uniformity of natureand causally depends on experience of constant conjunction of the appropriatesort, neither the uniformity of nature nor the constant conjunction figures as apremise in basic causal inferences.



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judgment. ‘x perceives that green tree’ does not imply ‘x perceives thatthe tree is green’ or even ‘x perceives that green tree as a green tree’.However, it does imply the existence of a green tree in front of x andthat x perceives that green tree as something, where ‘something’ is aplace holder for some contentful predicate. Below I shall consider towhat extent I.i and I.iv.2 encourage the idea that there is a use of‘impression of sense’ that applies to brute sensory awareness of phe-nomenal items.

I take it then to be the clear import of the passage at T. 86 withwhich I began that impressions of sense are to be understood as robustperceivings which as judgments are starting points for inferences to theunobserved. It is important, however, that one not conclude from thisthat impressions turn out to be more complicated than first thought,i. e., two mental acts, awareness plus judgment, or worse, inferencesfrom sense data to unobserved physical objects; rather, we should con-clude that an impression of sense as the first act of understanding is anact of judgment. The notion of content as what is understood orgrasped in an impression/judgment is an abstraction in the sense thatthe most basic cognitive act is a perceptual taking of an object in theenvironment, at least as far as I.iii is concerned. Impressions of senseare not maximally inlivened and inforced ideas. Perfect ideas of senseare (assertorically and practically) forceless copies of impressions ofsense. Hume does not operate with a logically prior concept of purerepresentational content and then distinguish among representationalacts those that are acts of pure understanding and those that are, byvirtue of a volitional act of assent, episodes of belief. The fact thatideas are copies does require us to say that an idea of outer sense is(representationally) of whatever the impression it copies is (representa-tionally) of. But that does not turn an impression of sense into an ideaplus assent, however construed, nor a belief in general into an idea plusassent. Cognitive content is what you get when you subtract assertoricforce from an impression of sense.11

Hume does not explicitly attack in the body of the Treatise a voluntaristic accountof belief that attaches assent to conception. In fact he complains that no one hasthus far bothered to give an account of belief.

This operation of the mind, which forms the belief of any matter of fact, seemshitherto to have been one of the greatest mysteries of philosophy; though no onehas so much as suspected, that there was any difficulty in explaining it. [T. 628]

11 Ken Winkler has pointed out to me that Thomas Reid (Inquiry. chpt. 2. sect. IV)defends a view very much like the one I am ascribing to Hume.




This act of the mind has never yet been explained by any philosopher, and there-fore I am at liberty to propose my hypothesis concerning it; which is, that it isonly a strong and steady conception of any idea, and such as approaches in somemeasure to an immediate impression. [T. 96 f. fn.]

Insofar as he himself provides a dialectical foil, it is a view according to whichconception becomes belief by adding more putative content, such as truth or exist-ence. He does, however, rely on the presumed falsity of doxastic voluntarism inarguing that belief does not arise from augmenting the content of a conceiving:

Secondly, the mind has command over all its ideas, and can separate, unite, mix,and vary them, as it pleases; so that if belief consisted merely in a new idea,annex’d to the conception, it would be in a man’s power to believe what hepleas’d. [T. 623 f.]

I think, therefore, it is helpful to see Hume’s view as positioned between two versionsof an intellectualist account of belief, the one he explicitly considers, that belief isan idea to whose object the idea of existence or truth has been added, and theCartesian/voluntaristic one I have been considering. On Hume’s view, as I have beeninterpreting it, belief is more basic than mere conception and an impression of senseis the most basic form of belief.

Moreover, the appendix provides some textual warrant for the claim that Humedid consider a voluntaristic version of belief in the course of arguing that belief isnot an impression distinct from a conceiving with which it is putatively linked. Pears(1990, p. 53 f.) disagrees and denies that Hume’s mention of an impression annexedto a conception “after the same manner that will and desire are annexed to particularconceptions of good and pleasure” [T. 625] is a reference to a Cartesian alternativetheory of belief. It is true that the alternative Hume is considering and rejecting isnot strictly Cartesian, since it is articulated within Hume’s framework of impressionsand ideas. However, the fact that Hume models the relation of this impression an-nexed to a conceiving on the relation of will and desire to their respective objectsshows that he is thinking of the impression of the alternative theory in conativeterms. If Hume were only interested in the manner of annexation he could have usedless obviously conative impressions of reflection as analogues.

II

Several difficult and important questions remain. As assertions howdo impressions of sense stand with respect to truth and justification?Specifically, as a premise in causal inference what does it take for animpression of sense to be justified? These are not questions Hume ad-dresses. Nonetheless, the pervasive naturalism of part iii suggests ananswer. First, in the matter of justification, it is reasonably clear thatone need not be in possession of a (linearly) justifying argument for animpression of sense functioning as a premise in causal reasoning for



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the impression to have positive justificatory status. I think this is rea-sonably clear for a number of reasons, besides the obvious fact that animpression of sense is the first act of judgment that lays the foundationfor inference to the unobserved. In basic causal (or probable) reasoningof the sort that Hume ascribes to most sentient creatures one need notuse as premises either the fact that one has had an experience of con-stant conjunction or the principle of the uniformity of nature.12 A forti-ori, one need not be in possession of justifying arguments for them aspremises in first-level just causal inferences.13

We infer a cause immediately from its effect; and this inference is not only a truespecies of reasoning, but the strongest of all others, and more convincing thanwhen we interpose another idea to connect the two extremes. [T. 96 fn.; cf. 103 f.,93, 225]

I take it further that Hume does not require of one engaging in prob-able reasoning that she be in possession of a justifying argument forthe impression-premise.

Now if one accepts the assimilation of impressions of (outer) senseto robust perceivings, as I have been suggesting and will continue toargue for, then although Bob’s impression of a dog on a certain occa-sion entails that a dog is causally present to Bob’s senses on that occa-sion, his impression of the dog that it is barking does not entail that itis barking. So obviously Bob’s impression as a judgment will not bejustified for him simply because all impression-judgments are true: theyare not. My guess is that Hume would accept some sort of reliabilitycondition as sufficient for the justification of impression-judgments, acondition they satisfy because ordinary sense perception is a reliablecognitive capacity.14

12 I concede that initially [T. 87] Hume speaks as though a premise from memoryreporting the observed constant conjunction is necessary for the occurrence ofeach causal inference. This, however, is clearly not his settled view. The only rolefor an explicit statement of past constant conjunction in settled causal reasoning,as opposed to more tentative erotetic causal reasoning, would be as a premisein a rationalist demonstrative argument or in response to a challenge.

13 The truth of each is a necessary condition for just causal reasoning. And ofcourse, the rationalist conception of probable reasoning Hume is attacking atT. 88292 requires that experience of constant conjunction and the uniformity ofnature both figure as premises in probable reasoning and furthermore that onebe able to justify (noncircularly) the principle of the uniformity of nature.

14 As I am reminded by Kate Abramson, Locke certainly ascribes independentepistemic authority to the deliverances of the senses “And this conformity be-tween our simple ideas and the existence of things is sufficient for real knowl-edge”. (Essay. IV.iv.4) See M. Ayers Locke Vol. I, London: Routledge, 1991,pp. 1552159, 1662172. Ayers, however, certainly does not ascribe such a view




Let me now shift to a more familiar question. Do force and vivacitydistinguish, as a matter of definition, an impression of sense from aforceful idea of comparable content? The answer to this question is“no”, whether or not one supposes that force and vivacity pertain toassertoric and motive force. But this is no surprise. Hume is the firstto note exceptions to the general claim that impressions have moreforce and vivacity than ideas. But then why are not hallucinations im-pressions, given that hallucinating a dagger floating within one’s reachhas both assertoric and action-engaging force? It comes as no surprisethat my answer is that hallucinating a dagger floating within one’sreach is not an impression because it is not a case of a dagger beingpresent to the senses. In contrast, an impression of a dagger floatingwithin reach is a case of a dagger being present to one’s senses. Andwhile this implies that there are no impressions of daggers in the ab-sence of dagggers, it does not imply that every propositional or impli-citly predicative impression of a dagger is true. So, for example, animpression of a dagger as floating within reach when in fact it is sus-pended by an unseen wire is a false impression, although what it is animpression of is present to the senses. In this then impressions of sensebehave just as acts of ordinary sense perception. Perceiving the F im-plies that an F is causally present to the perceiver’s senses (organs)and, typically, epistemically present as F. Misperceiving the F impliesperceiving an F but as what it is not.15

to Hume. Nonetheless, it seems to me perfectly plausible that in his positiveaccount of causal inference Hume may well be drawing on Locke’s familiar non-Cartesian conception of sensitive knowledge. In any case in I.iii.4 Hume freelyrefers to the independent authority of the memory and senses.

15 I am obviously raising delicate questions that cannot be fully discussed here. Inparticular, why is not what I am calling a false impression, i. e., a misimpression,say, of a dog as brown when it is not, strictly speaking, an impression of brown?Since when in Hume is a dog a proper object of a sense impression? Surely, theproper object of an impression of sense, at least of a simple impression of sense,is a proper or common sensible, something which one is aware of in its sensorycharacter. Without conceding that the proper objects of impressions are free-floating sensory features, we can meet this point by allowing a dog, through itscausal presence, to be an object of a sense impression as long as the impressionrepresents the dog as the F, where ‘F’ is a predicate standing for a proper orcommon sensible. Whether this experience is a misimpression depends onwhether the dog satisfies the definite description, ‘the F over there’. Whethersome aspect of the impression’s narrow content or that of another impressionsuitably related to it must get the object right, whether, that is, there must besome proper or common sensible, F, in whose guise the object appears such thatthe object is in fact F is a further question to consider.



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Hume, of course, makes none of these points explicitly. Nonetheless,there is ample warrant for supposing that he standardly treats the rela-tion of an impression of sense to its object as the relation of an ordinaryact of sense perception to its ordinary object.

All kinds of reasoning consist in nothing but a comparison, and a discovery ofthose relations, either constant or inconstant, which two or more objects bear toeach other. This comparison we may make, either when both the objects arepresent to the senses, or when neither of them is present, or when only one. Whenboth the objects are present to the senses along with the relation, we call this percep-tion rather than reasoning; nor is there in this case any exercise of the thought, orany action, properly speaking, but a mere passive admission of the impressionsthrough the organs of sensation. [T. 73], emphasis mine; also see T. 102

One who is committed to the more familiar Hume might try to meetthe challenge of this passage at T. 73 in the following way. The presenceof the objects is nothing other than the presence in mind of impressionsand their content. So in whatever way any object is present to a mindthis will be how it is present to the senses without implying the causalpresence of an object. One might cite T. 97 as supporting this thesis ofparity: “When we infer the existence of an object from that of others,some object must always be present either to the memory or senses[…]”. There are two responses. First, the general thesis of parity obliter-ates the distinction between observation and an inferred belief aboutthe unobserved, since it entails that having anything in mind on anyoccasion will count as something being present to the mind. The objectswhose existence is inferred will also be present. Second, the reference toorgans of sensation indicates that the presence of objects to a perceiverincludes the causal presence of external objects. Finally, the parity ofpresence as it applies to memory and the senses in the quoted passageonly shows Hume’s zeal to assimilate acts of memory to impressionsof sense in explaining immediate inferences to the unobserved. At T. 84he even refers to acts of memory as impressions.

Whatever occasion Hume’s discussion in I.v provides for revisingwhat he says in I.iii, at T. 73 he pretty clearly assimilates impressionsof (outer) sense to ordinary robust perceivings. The sort of case heseems to have in mind is a billiard ball case, one ball striking another.He initially, somewhat misleadingly, seems to imply that perception isreasoning because of the relational judgment involved, only to retractthe misassimilation because of the passivity of merely being affected bythe objects. Of course, on his own view, still to be presented, the dis-tinction between reasoning from the observed to the unobserved and




perceptual observation is not to be drawn in terms of passivity andagency, since causal inferences are themselves the effects of naturalcauses. It is, however, dialectically appropriate for him at least to intro-duce the distinction in these terms. And we certainly need not read thedenial of exercise of thought as any more than the absence of ratiocina-tion. Hume has already said that as a faculty of comparison, even inits passivity, perception involves the epistemic/cognitive presence of theobjects and the relation, as well as their causal presence. So there is noreason for the reader to infer from the passivity of perception and thefact that it does not involve the exercise of thought that what Humehas in mind is nonconceptual awareness of the sensory given.

And so if, on the contrary, Hume has assimilated impressions of(outer) sense to ordinary robust perceivings there is, prima facie, reasonto ascribe to him the consequences of this assimilation. Moreover, thesupposition that impressions of sense are ordinary acts of sense percep-tion makes good sense of Hume’s characterizing an impression of senseas the first act of judgment that lays the foundation for inference fromthe observed to the unobserved. The connection between sense-percep-tion and observation is obvious. Moreover, both exhibit the same flexi-bility with respect to logical form, a flexibility between propositionaland referential constructions, observing/perceiving that p and observ-ing/perceiving x. So it is perfectly reasonable that impressions of senseshould exhibit the same flexibility, and thus that impressions of sensesometimes occur as mental acts with individual objects and sometimes,as in the case of causal inference, as explicit judgments. What is curiousin all this is that Hume apparently leaves no room in this notion ofimpression for a purely contemplative nonrepresentational apprehen-sion of the sensory given such as later philosophers associate with theterm ‘sensation’. Impressions are not contemplative in that sense.Rather, they are representations of ordinary public objects whose forceand vivacity “renders them the governing principles of all our actions”.[T. 629]

III

I must now consider and respond to a number of obvious challengesto this interpretation of impressions of sense as involving the causalpresence of publicly observable objects. What about the various pas-sages in which Hume seems to intimate that our Cartesian access toHumean perceptions precludes distinguishing impressions from ideasby appeal to the causal presence of publicly observable objects?



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As to those impressions, which arise from the senses, their ultimate cause is, inmy opinion, perfectly inexplicable by human reason, and it will always be impos-sible to decide with certainty, whether they arise immediately from the object, orare produced by the creative power of the mind, or are derived from the Authorof our being. Nor is such a question any way material to our present purpose.We may draw inferences from the coherence of our perceptions, whether they betrue or false; whether they represent nature justly, or be mere illusions of thesenses. [I.iii.5. p. 84]

I will take up this passage first, since its proximity to the passagesfavoring my view makes it more immediately threatening. From aglobal standpoint Hume’s skeptical observation in this passage is noth-ing more than a reiteration of the moderating attitude he expresses inthe conclusion of the introduction at T.xviii2xix. However ambitiousand comprehensive Newton’s science of matter and Hume’s science ofhuman nature is, there is a limit to human knowledge. Metaphysicalquestions about ultimate principles and causes of natural phenomenacannot be settled because they cannot be settled by experience. Whenexperience-based explanation runs out explanation runs out. So whenthe metaphysical question is raised concerning the ultimate cause ofimpressions of sense Hume must plead ignorance. It is worth notingthat when Hume touches on the issue of explaining impressions ofsense at T. 8 he also pleads ignorance, but in deference to the anatom-ists. The causal mechanisms involved in the production of sensationare the proper subjects of natural and not moral philosophy.

Read from a more local standpoint the passage also does nothing tocontradict the claim at T. 73 that in fact impressions of sense are per-ceptions occasioned by ordinary objects acting on the organs of sensa-tion. The fact that we are not in a position to know with absolutecertainty that this is so only makes it unreasonable to endorse the claimon rationalist grounds of the sort Hume rejects. The situation withrespect to the principle of the uniformity of nature is analogous. Itsnegation is at least conceivable. Thus it is known neither intuitively nordemonstratively. And since it is a presumption of probable reasoning,there are no noncircular proofs for it. Yet only on the supposition thatHume accepts rationalist standards of reasonableness does it followthat Hume is arguing for a radically skeptical conclusion.

First, a minor point. Hume’s mention of pretheoretic ordinary ob-jects as candidates for causes of impressions of sense is continuous withhis previous explicit assumption and thus corroborates the obvious,that Hume has been assuming that impressions of sense are caused bytheir objects. It is not as though the question had not come up before




and Hume now, considering the question for the first time, issues aretroactive methodological edict to the effect that it is not to be as-sumed that impressions of sense are occasioned by the causal presenceof their objects. Second, it is not even clear to what extent the twomore exotic candidate explanations exclude the first. It is certainly truethat if either the author of our being causes impressions or our creativeand powerful minds do, then impressions do not arise immediatelyfrom their objects. But all three could be concurrent causes, and if notall three at least God and object, in which case impressions of sensewould still differ from ideas in virtue of the causal presence of theobjects.

I suppose one might cite, in rejoinder, Hume’s subsequent listing of the evalua-tions, truth, falsity, just representation of nature, and illusion of the senses, andargue that concurrence is not a possibility Hume is entertaining. The argumentwould be that each of the three candidate causes of impressions, God, self-impressingmind, physical object, is to be paired uniquely with exactly one of three distinctevaluations, presumably, God with falsity, self-impressing mind with illusion of thesenses, and physical object either with truth or just representation of nature. Oneresponse is to point out that if there were only two distinct evaluations, truth andfalsity, then there would be no such presumption in favor of each of the three candi-date causes operating only on its own. And indeed, the most natural reading of thepassage only finds two evaluations, truth and falsity, glossed respectively as justlyrepresenting nature or illusion. So unless Hume is independently assuming that theauthor of our being is a deceiver or Berkeleian in his operations, there is clearlyroom for our impressions to be true and to justly represent nature as joint productsof the objects and the author of our being.

My point, of course, is not that the only undecidable possibilities Hume mentionshere are the ones compatible with his initial naturalist assumptions. Rather, they donot matter at all. None is an impediment to the progress of the Humean science ofhuman nature and none requires retraction of any assumptions made thus far.Hume’s science of man is still a science of minds embodied in human bodies in turnembedded in a natural and social world. Why then does Hume raise the speculativequestion? For local dialectical purposes. He is about to examine the inferential tran-sition from impression to idea and the nature and quality of the inferred idea. Sincethis is the centerpiece of Book I he wants to bring along as many readers as hecan, whatever their metaphysical prejudices regarding the causes of perception. Hisaccount of causal inference is one that focuses on the psychological dynamics of theprocess and can be appreciated, even if not fully, without sharing his assumptionthat impressions of sense are caused by their objects.16

Still, one might think that it makes better sense to see Hume drawing the idea-impression distinction as follows. After appealing to relative force and vivacity as a

16 In this context also consider T. 102.



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preliminary way of drawing the distinction Hume then sets to work sorting percep-tions by the mental operations that produce them. Ideas of memory and imagina-tion, for example, differ by being products of different kinds of cognitive operations.More generally ideas, those perceptions typically less forceful than the perceptionsthey resemble, are caused by their more forceful counterparts, i. e., impressions ofsense (inner and outer), which are not the causal products of perceptions. Theselatter perceptions, impressions of sense, while they no doubt have causes, althoughunknown, are distinguished from ideas simply in virtue of not being caused by per-ceptions.17 So there is no reason for a reader to suppose that Hume relies on publicobjects as the causes of impressions of (outer) sense to distinguish them from theircounterpart-ideas which may approach them in force and vivacity.

There are several considerations against this alternative. First, it seems to metantamount to foisting on Hume the method of solipsism for the sake of accommo-dating the very reading of T. 84 which I have just tried to replace. The reading Ihave provided is one I hope to sustain with the rest of my argument, in particulara close reading of the opening pages of the Treatise. Second, it is not at all clearhow an account of the causal history of a hallucination will distinguish it from animpression, if one cannot independently identify the impressions except as thoseperceptions that are (i) typically more forceful than their less forceful resemblingcounterparts and (ii) not caused by perceptions. (One cannot even say that impres-sions are caused by something other than the mind whose impressions they are,since the hypothesis of self-impressing minds is still on the table). There are severaldifficulties here. Hume will be unable to contrast hallucinations with veridical experi-ences. Moreover, hallucinations are not adequately explained by a causal historythat refers only to perceptions, even where that history includes disorderly passions.There is work here too for the anatomists. Finally, Hume’s science of the mindcannot unfold from a first person direct survey of perceptions that are to be sortedinto impressions and ideas according to their dynamic relations, since he only hassecondary ideas of the perceptions to work with, even if he has direct nonrepresenta-tional access to the occurrence of each perception.

All that notwithstanding, one might renew the objection against myclaim that the objects of impressions of (outer) sense are ordinary pub-lic objects by citing the closing paragraphs of I.ii.6.

We may observe, that it is universally allowed by philosophers, and is besidespretty obvious of itself, that nothing is ever really present with the mind but itsperceptions or impressions and ideas, and that external objects become known tous only by those perceptions they occasion. To hate, to love, to think, to feel, tosee; all this is nothing but to perceive. […] Now since nothing is ever present to themind but perceptions, and since all ideas are derived from something antecedentlypresent to the mind; it follows, that it is impossible for us so much as to conceiveor form an idea of any thing specifically different from ideas and impressions.[T. 67]

17 Garrett (1997, p. 26) may seem to sponsor such a suggestion.




This passage is not evidence against the view I am defending, but,instead, confirms it. Perceptions as mental acts are (nonrepresentation-ally) accessible. However, that apparently does not preclude objects ofimpressions of sense from being known as they occasion perceptions,i. e., as objects causing impressions in the perceiver. Now one mightargue that the context of the passage tells otherwise. Hume is arguing,one might point out, that since nothing but perceptions are ever presentto mind (and perceptions are the only source of content), “it is impos-sible for us so much as to conceive or form an idea of any thing specifi-cally different from ideas and impressions”. This looks like Hume athis Berkeleian best, until one considers what he means by ‘specificallydifferent’. The species in question is not that of mental act but that offeatured object of mental act. His point then is that in conceiving theexternal existence of something, which is known by causing perception,we are not conceiving it as having features different than the ones ob-jects of impressions have, as though it were an I-know-not-what spatialitem causing impressions of sense possibly possessed of none of thecommon and proper sensible features of objects of impressions. Thatis, to conceive of the external existence of objects as specifically dif-ferent from the objects of perception is to go beyond the naive realismof the vulgar system and entertain the metaphysical realism of doubleexistence.18

Indeed, what of these two systems and the footnote’s forward refer-ence to the dark passages of I.iv.2, the objection might resume. Thisrenewed challenge rests on a headier draft of legendary Humean skepti-

18 Fred Wilson (“Is Hume a Skeptic with regard to the Senses?”, Journal of theHistory of Philosophy 27 (1), 1989, pp. 49273) argues that in speaking of a rela-tive idea of specifically different objects [T. 68] Hume is preparing his eventualdefense of the philosophical doctrine of double existence. Wilson claims thatHume endorses a critical realist version of double existence. I find, somewhatironically, that I agree with Donald Livingston (“A Sellarsian Hume?”, Journalof the History of Philosophy 29 (2), 1991, pp. 281290) in his criticism of Wilson’shandling of the idea of specifically different ideas for I.ii.6, even though thecriticism is undertaken in defense of Popkin’s traditional skeptical interpretationof Hume. I, of course, agree with Wilson’s general view that the skeptical importof many of Hume’s arguments is in the service of undermining Cartesian intellec-tualist conceptions of reason. At the same time, however, I find myself agreeingwith Livingston (pp. 286287) when he claims that Hume is arguing for the pri-macy of the vulgar system and for the self-destructive character of the attemptto achieve radical philosophical autonomy. Livingston, I believe, may have over-looked the persistence of the primacy of the vulgar system even in the argumentsthat purport to establish the incoherence of the vulgar system.



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cism that includes not only the claim that there is no just inference fromour Cartesianly accessible perceptions to the distinct and continuedexistence of bodies, but the further claim that to believe, as we unavoid-ably do, in the latter is to believe in a mind-made-fiction.

This is obviously not the occasion to revisit in full the argument ofI.iv.2 and assess the complicated relation between the nature-sanc-tioned belief of the vulgar and the philosophical doctrine of doubleexistence discredited by Hume. What I can do is try to defend a charac-terization of I.iv.2 that explains it in relation to what I have been sayingabout impressions of sense. I will begin with the obvious: the (distinctand continued) existence of bodies is a point which we must take forgranted in all our reasonings.19 Indeed, it is a point Hume takes forgranted even as he conducts experiments to demonstrate the falsity ofthe vulgar’s belief that what we strictly perceive are bodies with a dis-tinct and continued existence.

‘Twill first be proper to observe a few of those experiments, which convince usthat our perceptions are not possessed of any independent existence. When wepress one eye with a finger, we immediately perceive all the objects to becomedouble, and one half of them to be removed from their common and naturalposition. But as we do not attribute a continued existence to both these percep-tions, and as they are both of the same nature, we clearly perceive that all ourperceptions are dependent on our organs and the disposition of our nerves andanimal spirits. This opinion is confirmed by the seeming encrease and diminutionof objects according to their distance; by the apparent alterations in their figure;by the changes in their colour and other qualitities, from our sickness and distem-pers, and by an infinite number of other experiments of the same kind; from allwhich we learn that our sensible perceptions are not possessed of any distinct orindependent existence. [T. 210]

Let me concede the obvious. The notion of an impression of senseemployed in the account of causal inference in Part III as I have inter-preted it in a certain sense stands idly by when Hume shifts his atten-tion from reasoning at the executive level, so to speak, to the problemof unconsciously constructing a representation of a world of stable andenduring objects out of fleeting glimpses. Here we have a single notionof sensation that does not distinguish between the ideas and impres-sions of sense of Part III. Earlier an idea was distinguished from theimpression from which it was inferred by the fact that in the case ofthe impression an object was present to the senses. In whatever sense

19 Baier (1991, p. 103) links this supposition and the characterization of mind inde-pendent material bodies as fictions to Kant’s notion of the synthetic a priori.




an idea had an object it was not a case of an object being present tothe senses. That is why causal inference is from the observed to theunobserved. To dwell on the obvious, if impressions as observationsdid not involve the causal presence of their objects then inferentiallyintroduced ideas could equally claim the status of observations. Butnow in I.iv.2 it looks as though what one would be inclined to identifyas an impression has an object in the very same sense as an idea hasan object. At any rate that seems to be the import of the passage inwhich Hume states that there is nothing to choose between what wouldbe a veridical perception and its twin in the case of double vision. Theperceptions, that is their objects, are of the very same nature, phenom-enal wraiths.20

Yet in this passage of the Treatise, even as he argues that what wedirectly perceive are fleeting dependent entities, he remains clearly com-mitted to the claim that we do perceive bodies even though how theyappear depends on our bodies and how they are affected by the formerin various circumstances. That is, he is still operating within a robustnaturalist framework of public objects even as he undermines its viabil-ity as a first person perspective by arguing that the noninferentiallyreportable objects of sensory consciousness are phenomenal wraiths,although bulked up into convenient fictions with virtual distinct andcontinued existence.

The question remains why Hume appears to forsake the vulgar con-ception of objects of sense with which he had earlier distinguished im-pressions of sense from their corresponding ideas. My initial response,to reiterate, is that he does not really forsake it. The familiar argumentshe uses to induce the familiar sense data inference in order to show thefalsity of the vulgar conception rely on the theorist’s naive use of thevulgar conception. The psychological subject about whom Hume is the-orizing is not permitted to sort his perceptions by appeal to externalcausal factors. However, Hume, the theorist, makes use of causal con-siderations in ascribing intermittent impressions to a subject who willconnect them with the simple supposition of continued existence. (Howwould Hume characterize the mental acts by which he, the theorist,identifies the continuents that are the causes of perception in the sub-jects to whom sensory stimulation is being meted out?)

Whatever else one is to make of I.iv.4, “Of the Modern Philosophy”, the conclu-sions of causal reasoning that Hume claims to be in total opposition to the doctrineof the continued and independent existence of body similarly presuppose the vulgar

20 The expression ‘phenomenal wraith’ is Baier’s (1991, p. 105).



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system. The familiar arguments, rehearsed with apparent approval by Hume[T. 226 f.] for the claim that what we perceive of objects is not in them begin withassumptions about the varying effects on perception due to unchanging robust ob-jects operating on us in varying circumstances:

Upon the difference of their external situation and position: Colors reflected fromthe clouds change according to the distance of the clouds and according to theangle they make with the eye and the luminous body. [T. 226]

The causal reasoning issuing in the interim conclusion “that many of our impressionshave no external model or archetype” [T. 227] depends on the causality of bodieswith a distinct and continued existence. Nothing Hume says at the end of the sectionchanges that.

It is in part because Hume is interested in how, sub-epistemically, as it were, asubject comes to represent a lasting objective world in response to sensory stimula-tion produced by objects in the world that he brings into view what might be iden-tified as a more familiar notion of sense-impression. Hume’s interest in the intro-spectively inaccessible psychological mechanisms involved in producing the belief inthe distinct and continued existence of bodies is not epistemological in the traditionalsense. In accordance with the opening remarks of I.iv.2 he is not primarily concernedwith the question of justification. The unconscious ratiocinative processes Humeascribes to the imagination to explain the vulgar belief that what we perceive enjoysan uninterrupted existence do not involve beliefs that provide inferential support tothe vulgar belief in the continued existence of what we perceive, at least not in thesense that the vulgar could rehearse justifying arguments appealing to these beliefsas premises.

It requires more than a little patience to sort out the different levels at whichHume operates in accounting for the propensity to unite broken appearances by acontinued existence. He also does not clearly distinguish, on the one hand, comingto believe on a certain occasion, against the general background belief that there arebodies with a distinct and continued existence, that a sequence of discontinuousviewings are viewings of the same object and, on the other hand, acquiring thegeneral background belief in the first place. On Hume’s account, the mind, by iner-tia, fails to discriminate among resembling perceptions and treats them, namely,their objects, as identical. Yet interruptions in a sequence of resembling perceptionsleads to the conclusion that the perceptions are not of the same object.

The smooth passage of the imagination along the ideas of the resembling percep-tions makes us ascribe to them a perfect identity. The interrupted manner of theirappearance makes us consider them as so many resembling, but still distinct be-ings, which appear after certain intervals. The perplexity arising from this contra-diction produces a propension to unite these broken appearances by the fictionof a continu’d existence […] [T. 205]

This sensitivity to contradiction is certainly not exercised at the level of noninferen-tially reportable beliefs. Peasants and children have it. But given this sensitivity tocontradiction on the part of something in us, distant windmills of unconscious men-




tal activity, it would seem that the fiction of the continued existence of a perception,i. e., a mind dependent perceptual content, would provide yet another occasion forthe exercise of this sensitivity. For Hume is quick to point out [T. 206] that the ideaof a perception existing without being present to the mind is, or at least appears tobe, a palpable contradiction. Hume then argues that it is not a contradiction byanticipating his discussion of personal identity. Since a mind is nothing but a heapof variously related perceptions, it is at least possible for a perception to exist with-out being an element of such a heap. [T. 207] One can only wonder whether Hume’sview is that the unconscious mind of the vulgar has recourse to Hume’s own theoryof personal identity.

When, however, Hume does raise the traditional epistemological ques-tion of justification at T. 212 it is to discredit the philosophical doctrineof double existence. We must be careful, though, to draw a distinctionbetween the doctrine of double existence of the Cartesians, for exam-ple, and the view Hume is operating with in the very course of repro-ducing a version of the Cartesian quandary, even if Hume does notdraw it and may be incapable of drawing it. The official doctrine ofdouble existence is a metaphysically realist view. The objects whoseexistence cannot, according to Hume, be justly inferred, are conceivedas specifically different from what is perceived. They are hypothesizedas spatial items that ultimately cause impressions of sense and whoseexistence does not depend on their being possible objects of intuitionin Kant’s sense. Neither reason nor experience can confirm the exist-ence of such items. When Hume sets out to show the falsity of thevulgar system by reflecting on the variability of perception in the faceof the invariance of the objects causing perception, he would appear tobe operating, albeit in bad faith, with the metaphysical doctrine ofdouble existence. But he is not. Without acknowledging it, the objectsthat he claims to be the invariant causes of varying and fleeting percep-tual contents are conceived within the vulgar system. That is, the stancethat Hume as theorist takes toward his own impressions and their ob-jects is the stance of common life. He is no different from those philos-ophers who “[…] upon leaving their closets, mingle with the rest ofmankind in those exploded opinions, that our perceptions are our onlyobjects, and continue identically and uninterruptedly the same in alltheir interrupted appearances”. [T. 216] At the moment Hume drawsthe sense data inference he is implicitly endorsing a view that looks likethe doctrine of double existence. There are the spatial items that causeperception and there are the reified fleeting and varying perceptualcontents of the perceptions thus caused. However, the former spatialitems decked out in primary and secondary qualities are ones to whichHume as theorist in the field has noninferential access through his own



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impressions which have not yet been reconceived according to the the-ory under construction.

Philosophers who accept the epistemological view that the only data/evidence a self-conscious epistemic agent has to go on are his Carte-sianly accessible perceptions of sense will find themselves unable toreason justly to the conclusion that there are objects categorically dif-ferent from, though somehow corresponding to, the objects they per-ceive.

The trouble Hume makes for himself and the reader in I.iv.2 stemsfrom two central conflations. (1) He inevitably conflates (i) the role ofperception as input into a cognitive system whose activity is appercep-tively inaccessible to the conscious epistemic agent and whose outputis the fiction of the distinct and continued existence of bodies with (ii)the role of perception as a sensory state apperceptive beliefs aboutwhich are supposed by the intellectualist tradition to function in self-conscious epistemic agents as foundational premises grounding thesupposition of the continued existence of bodies. (2) He conflates (iii)the sub-epistemic reason-like considerations his theory ascribes to thefaculty of imagination in anyone who believes that bodies have a dis-tinct and continued existence with (iv) ordinary possible epistemicreasons for believing that bodies have a distinct and continued exist-ence. We can see both conflations at work at the end of I.iv.2 as heveers toward despairing skepticism. Once the supposition is criticizedand cogitations of the imagination that produce the supposition areconsidered as possible epistemic reasons for believing the suppositionHume is unable to infer from his Cartesianly accessible perceptions tothe continued existence of bodies. When you look at this page all yousee is a fleeting image whose character depends on the objective circum-stances of perception which are not available to you, although youbelieve of what you see that it has a distinct and continued existence.My second person description of your predicament presumes that it isnot my predicament. However, once I switch perspectives and see my-self as in the predicament my theory has placed you in, I cut myself offfrom my initial robust naturalist framework and find myself uncon-vinced by the considerations, converted into possible reasons, that ac-cording to my theory produces from resembling and intermittent per-ceptions the belief in the distinct and continued existence of bodies. Ifind myself in a skeptical swoon from which neither demonstrative norprobable reasoning offers escape. I can try to remind myself that thereasons I had for thinking that the supposition was false presupposedthe truth of the supposition and that the data my theory in part ex-




plains include real objects and not just mind-made fictions postulatedby the theory. However, once we are in the grip of the theory as itapplies to each of us, carelessness and inattention alone can afford usany remedy.

Let me end this discussion by acknowledging that I.iv.2 occasionsthe following reconsideration of our interpretation of impressions ofsense. Given the vast machinery and resources needed to produce thevulgar belief in the distinct and continued existence of bodies, it is clearthat taken in isolation no perception of the sort Hume treats in thissection as an immediate sensory impingement is intrinsically an impres-sion of an object as having a distinct and continued existence. To theextent that our interpretation of the notion of an impression of senseat work in I.iii implied otherwise it was misleading. However, to theextent that habits of imagination make a seamless contribution to thecontent of sensory consciousness (the torsoless legs of T. 625) the im-pressions of sense thickened by the imagination will constitute percep-tual awareness of ordinary objects as having a distinct and continuedexistence. And thus I take it that the impression-premises of causal infer-ences discussed by Hume in I.iii have been thickened by the imagin-ation in various ways. It must also be pointed out that even the thin-ner sensory impingements of I.iv.2 still remain impressions of ordinaryobjects of sense having a distinct and continued existence, even if notas so existing. And finally, it must be emphasized that the assertoriccharacter of impressions of sense, which was central to the argumentsof I.iii, is left intact. There is no hint in I.iv.2 that an impression ofsense as even the most minimal perceptual taking lacks assertoric char-acter and that its assertoric character is anything other than its forceand vivacity as an impression. Hume appeals to the force and vivacityof impressions of memory as producing the assertoric character of thebelief in the continued existence of bodies [T. 2082210]

IV

As a final test of the claim that an impression of sense differs from itscorresponding idea by the fact that the impression involves the concur-rent causal presence of its object, let us return upon our footsteps to theopening pages of the Treatise. The first three sentences, where Humeintroduces the distinction between impressions and ideas, might giverise to the suggestion that he is proceeding solipsistically and that whatalone distinguishes an impression of sense from an idea is force andvivacity as an introspectible feeling.



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All the perceptions of the human mind resolve themselves into two distinct kinds,which I shall call impressions and ideas. The difference betwixt these consists inthe degrees of force and liveliness, with which they strike upon the mind, andmake their way into our thought or consciousness. Those perceptions which enterwith most force and violence, we may name impressions; and, under this name,I comprehend all our sensations, passions, and emotions, as they make their firstappearance in the soul. [T. 1]

Why, if my interpretation is correct, has Hume relied exclusively ondegrees of force and vivacity to introduce the distinction between im-pressions and ideas? Why is there no mention of the causal presence ofobjects of sense-impressions? The answer is simple. The distinctionHume draws between impressions and ideas does not discriminateamong impressions of outer sense, impressions of bodily pleasure andpain, and impressions of reflection.21 He needs a single feature thatgroups sensations of both sorts and passions under one heading.

Of course, Hume’s grouping of seeing and hearing with anger andlove is notoriously vexing. Beyond the obvious question of why theseitems belong together one wonders how a single relation of resem-blance will cover the fact that ideas resemble both types of impressions.The difficulty is that impressions of outer sense and their ideas seem tofall together as representations, whereas impressions of reflection, evenif possessed of content, and their ideas do not. The best one can do issuggest that an idea resembles an impression that is representationallyof something, e. g., an impression of a red sphere, by being of what thelatter is of, while an idea resembles an impression of reflection, e. g.,an impression of anger by being of what the latter is. Similarly, ideasof bodily pleasures and pains will resemble their corresponding impres-sions of sense by being of what the latter are. One might suppose thatthe slogan “no unfelt pains” is supposed to capture the idea that painis always attended by the sufferer’s awareness of it. In that case an ideaof pain will resemble an impression of pain by being of what the atten-dant act of consciousness is of.

I should also mention by way of final reminder that any interpreta-tion of force and vivacity faces the difficulty of finding a single featurecommon to all impressions. Any feature pertaining to representationalcontent, for example, will obviously fare badly in accommodating im-pressions that lack content. So, for example, if the impression of painis the state of being in pain and not the apperceptive awareness of

21 He does not even draw the distinction until section ii.




pain then the force and vivacity of the impression of pain will notbe accommodated by a feature pertaining to representational content.Similarly, if passions have no representational content, as some believe,then again features pertaining to representational content will havenothing to do with the force and vivacity of passions. On the otherhand, if passions do have representational content, it still seems prettyclear that their force and vivacity is not captured by features of repre-sentational content. The degree of force and vivacity of an episode ofpride is not obviously a function of, say, the clarity and detail of myidea of my fine house. The force and vivacity of a desire to drink waterpertains, one would suppose, to its motivational efficacy and not to themanner in which water is depicted. Force and vivacity as a dimensionof the attention a perception draws to itself does not fare any better asa candidate. The only reason one’s attention is drawn to the impres-sions of the marks on the page of one’s copy of the Treatise is that theauthor calls attention to them. The calmness of the calm passions is inpart their being less importunate in calling attention to themselves thanthe violent passions which they often oppose. However, the calmnessof one’s desire to take the foul tasting medicine for the sake of one’sgood is no measure of its force and vivacity. In successfully opposingthe visceral aversion to the medicine, a violent passion, the opposingcalm passion shows itself to be of greater force and vivacity.

To return, what an impression of sense shares in common with animpression of reflection, in contrast to their corresponding ideas, is agreater degree of force and vivacity and not the causal presence of aperceptual object. While a sense-impression of an apple, on the view Iam defending, involves the causal presence of an apple, a desire to eatone need not. So mention here of the causal presence of perceptualobjects would not suit Hume’s immediate purpose of drawing a globaldistinction between impressions and ideas.

Still, one might well ask how the force and vivacity of seeing is linkedwith the force and vivacity of desire or anger. The link, I believe, isresponsiveness; in the case of impressions of sense, initial cognitiveresponsiveness and collateral inferential responsiveness, in the case ofimpressions of reflection, behavioral and further psychological respon-siveness.22 In particular, I think that vivacity and liveliness mark thedistinctive vital responsiveness of sentient bodies. It is this that links

22 Again, I realize that I am not doing justice to the full range of impressions ofreflection.



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the force and vivacity of the two kinds of impressions.23 They are alsolinked by analogous dependencies. Inferential responsiveness involvesa background of experience relevant to the content of the impression-premise. Behavioral responsiveness in the case of passions involves abackground of beliefs relevant to the content of the passion.

Moreover, in addition to its assertoric and inference-initiating char-acter an impression of sense as forceful and lively also provides a start-ing point for action, given an appropriate impression of reflection. Theforce of seeing involves both judgment and a propensity to act, as wellas a propensity for passions that may not be as directly action engagingas desires. Or rather, judgment or belief is in part constituted by apropensity for various passions. Just as the force of wanting to eat anapple is in part constituted by the propensity to move toward the placewhere one believes an apple to be, the force of seeing an apple is inpart constituted by a propensity for apple-involving passions. So inaddition to an analogy there is a genuine mutual dependence betweenthe force and liveliness of the two kinds of impression.

Before directly accommodating this conception of force and vivacityto Hume’s cavalier claim that “Every one will of himself readily per-ceive the difference between feeling and thinking”, we should take upHume’s rather curious introduction of ideas. The first examples Humegives of either ideas or impressions are examples of ideas by way ofostension of sorts:

By ideas, I mean the faint images of these in thinking and reasoning; such as, forinstance, are all the perceptions excited by the present discourse, excepting onlythose which arise from the sight and touch, and excepting the immediate pleasureof uneasiness it may occasion. [T. 1]

Several things are worth noting here. As faint images of impressionsideas stand as secondary to the originals they are images of. Thus it isnot a genuine empirical discovery that if a given token-idea is an imageof a token-impression then the impression is temporally prior to theidea. More important is the example itself. In an early show of charac-teristic playfulness Hume points to the perceptions excited in the reader’sthought by the text itself as examples of ideas. (This encourages the

23 One might also suppose that the force and vivacity of impressions of bodilypleasure and pain in part pertains to behavioral responsiveness. This would in-clude both nonmediated reflexes such as flinching and recoiling from hot irons,as well as mediated behavioral responses, taking medicine prompted by the ap-propriate beliefs and the desire to get well prompted ultimately by the discom-fort.




view of (perfect) ideas as meanings rather than pictures, since he limitsthe ideas in this example to those perceptions excited by the markson the page as symbols none of which refer to anything picturable withthe possible exception of the words ‘human’ and ‘strike’). He goes outof his way to make sure that no one supposes that the perceptionsarising from merely looking at the marks or holding the book or suchpleasure or uneasiness attending the reader’s understanding of the textare ideas. These latter perceptions are presumably impressions. Thisraises two very curious points. First, insofar as we are attending to thediscourse, the ideas, i. e., what Hume is saying, and not to the symboltokens by which it is conveyed or to the book in our hands, it is notat all clear that these ideas lose in a vivacity contest with the visual andtactile impressions. But the impressions are supposed to be greater inforce and vivacity. If Hume is assuming that the impressions of thepage are of greater force and vivacity than the ideas excited by readingwhat is on the page then force and vivacity must be something otherthan the attention getting capacity or richness in content of what ismerely understood. Here is a suggestion. The contrast between theideas conveyed by the words on the page and the tactile and visualimpressions does not depend on the context of attending to the ideaswhile ignoring the marks on the page which convey them, though itcan be sustained in such a context. Just consider seeing and feeling abook. In seeing and feeling the book the reader takes there to be abook with black marks on its pages. In understanding the words thereader may be pleased or put off (but these are impressions we are toldto ignore). He or she may even believe what Hume writes, but thedegree of belief is unlikely to approach the degree of belief involved inperceptually taking there to be a book with black marks on its pages.(As one reads does one believe what Hume says more than one percep-tually believes in the existence of his or her copy of the book in whichhe says it?) Now even in the case where the visual and tactile impres-sions are concurrent with the ideas we can still make sense of thegreater force and vivacity of the former. For if, as I have been arguing,the greater force and vivacity of the impressions of sense is greaterassertoric force, then although one might be paying no attention to themarks on the page in their nonsymbolic character, one’s mind is stillfilled with perceptual beliefs, albeit of a somewhat dispositional charac-ter, in contrast to merely understanding what Hume is saying or weaklybelieving it. One knows how to answer, if asked, whether the print isgreen or the paper pink, whether one has a copy of the Treatise. Hume,



284 Cass Weller

of course, may also be relying on the assumption that the typicallygreater force of an impression of sense is due to the causal presence ofthe perceptual object and indexical features of impressions of sense.

The second curious point arising from the example is that Humedoes not at all seem to be conducting his investigation from behind aveil of ignorance. There certainly is no explicit pretense to methodologi-cal purity that requires holding in abeyance commitments to the exis-tence of books and readers as physical objects. He goes out his way tocontrast the experience of understanding words with that of touchingand seeing the book one is reading. At T. 3, even as he reiterates theclaim that ideas and impressions differ in degree not nature, he refersto an idea of red which we form in the dark and an impression [of red]which strikes our eye in sunshine. What this shows is that Hume doesnot scruple to mark the distinction between an impression of sense andits corresponding idea in terms of veridical perception occurring in thepresence of physical objects and thought occurring in the absence ofits objects. Notice that it is this way of marking the distinction whichis at work when Hume concedes that ideas sometimes approach im-pressions in strength and impressions sometimes approach ideas inweakness. In dreams, fever or madness perceptions sometimes reachthe pitch of impressions. The approach of ideas to impressions of sensein force and vivacity is best construed in term of degrees of belief. Whatkeeps these experiences from being impressions is the fact that they arenot caused by objects that would make these experiences observationsof objects present to the organs of sensation. Hume is obviously relyingon the fact that impressions are what occur in ordinary wakeful percep-tual experiences such as seeing that there is a green book on the table.And while they do not differ in nature from forceful and lively ideas,they do differ from them in their proximate causes.

When Hume cavalierly says that “Every one will of himself readilyperceive the difference between feeling and thinking” I do not think weneed to understand the claim within the constraints of methodologicalsolipsism. The point of the remark is clearly to appeal to a pretheoreti-cal grasp of the difference between feeling an ordinary object, a book,say, and thinking about it, as well as the difference between feelingangry and believing of someone that she is angry. The particular caseHume has in mind is, of course, the previous case of the ideas excitedby the words on the page contrasted with the visual and tactile impres-sions excited by the book. Everyone can tell the difference betweenunderstanding the abstract ideas conveyed by words on the page andthe perceptual experience of seeing and handling the book. And even




if there are experiences in which one might mistake an idea of sensefor an impression of sense, generally one can tell the difference betweenlooking at one’s copy of the Treatise and thinking about the color ofone’s copy of the Treatise with one’s eyes closed. One might furthersuppose, however, that Hume is encouraging the reader to assume thatin ordinary cases one can rely on an introspectible difference in forceor vivacity to tell whether one’s experience is an impression of sense oran idea of sense. This is not to be confused with appealing to the coher-ence of one’s perceptions to justify the claim that one’s current experi-ence is a seeing and not merely a seeming. The question, rather, wouldbe how the force of an impression presents itself were we to try todetermine whether it is an impression by considering its force. Butnotice again that although the question is how the force of an impres-sion of sense makes it feel different from a corresponding idea, we arestill assuming that the two kinds of experience also differ in theircauses. So the question is how the force of seeing a publicly observableapple makes it discernibly different from thinking about the apple inits absence. Now if what I have said about force and vivacity is correctthen discerning, in the first person, the difference between feeling andthinking on the basis of force and vivacity is to be explained in termswhich involve assessing degrees of belief and practical engagement, evenif Hume is not providing this explanation in these opening sections ofthe Treatise. In discerning the force of a putative impression of sense onewould be discerning strength of belief, propensity to infer from, and like-lihood of going where in one’s immediate environment the perceptionrepresents the object to be, should an appropriate desire arise.

The only problem I see in this is an objection along the followinglines. In reporting an experience as an impression rather than an ideain virtue of discerning greater force and vivacity one would apparentlybe discerning a disposition associated with the experience. But a dispo-sition is not anything an empiricist of the sort Hume is thought to bewould acknowledge as an object of introspective reporting. I have tworesponses. First, Hume would not regard degree of belief as merelydispositional. Second, it seems to me that if the rest of my argument iscorrect then force and vivacity have an irreducibly dispositional dimen-sion and were so recognized by Hume. The dispositional aspect in thereportabilty of impressions is really only going to be a probem if Humeis an empiricist of the sort he was once standardly thought to be, thatis, a methodological solipsist concerned to provide an epistemic recon-struction of his beliefs in terms of atomistic experiences that sort intothe pictorially more and pictorially less vivid. I hope to have providedreasons against this presumption.



why hume is a direct realist

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