1 By ‘the presence of relations in experience’ I mean that relations are not produced by the mind but are immediately given along with objects, whether or not they are consciously observed or noticed.

2 James emphasizes an unbroken streamlike continuity of experience that is contributed by experience of relations obtaining among experienced objects. He argues that this emphasis sets his ‘radical empiricism’ apart from Hume's empiricism. He argues that we are not subject to multiple discrete experiences, but to one unified experience. Of course, we can talk about an experience of a stomachache I had last night and an experience of a taste of coffee I am having now, in which case there is surely a break between them. But, as these instances of experience are undergone, there are all sorts of other feelings surrounding them extending backwards and forwards so that there is in fact no break existing anywhere between them. Similarly, we can talk about a portion of river twenty meters east and a portion of river where I am standing and point out that there is a definite difference between these two portions of the river (say, with respect to water quality), and distinguish these portions of the river; and yet there is in fact no break between them as there is twenty meters of water flowing between them. We can talk about different portions of a stream of experience in this abstract way as if they were two different experiences, but this abstract way of talking does not reveal the structure of experience itself.

3 References to Hume's Treatise of Human Nature will be shown in the text, coming in two parts. The first part is the Norton & Norton edition (New York, NY: Oxford University Press 2000), abbreviated as ‘T’ followed by book, part, section and paragraph numbers, or in the case of the Appendix, ‘App’ and paragraph numbers. The second part is the L.A. Selby-Bigge & P.H. Nidditch edition (New York, NY: Oxford University Press 1978), abbreviated as ‘SBN’ followed by page numbers.

4 An idea of space can also be an idea of tangible points; as he observes that ‘the idea of space is convey’d to the mind by two senses, the sight and touch’ (T 1.2.3.15; SBN 38).

5 Pixels are appearing in a spatial matrix on the screen, and no matter how small it is, one pixel is spatially extended. Hence, I am aware that the analogy here does not completely illustrate the situation at issue, for Hume's colored point, a minima sensibilia, is not spatially extended, and extension is supposed to come into being in our perception only when two or more colored points come together, and thus it should not be assumed to begin with. But I only intend this analogy to show how our visual impressions are supposed to be constituted by Hume's colored points.

6 Lorne Falkenstein forcefully argues that ‘the manners of appearance,’ or ‘the manners of disposition,’ of simple impressions are ‘ordered arrangements of them,’ which refer to something over and above a collection of simple impressions in a compound, and they are initially there to be experienced along with simple impressions, ‘Hume on Manners of Disposition and the Ideas of Space and Time,’ Archiv für Geschichte der Philosophie, 79 (1997), 181-90.

7 The imagination is one of the two faculties by which ideas are brought about in the mind; the other faculty is the memory (Treatise, I.i.3).

8 When I see a picture of my niece and think of her, my seeing the picture as of my niece is not part of the explanation of the resemblance association at work here; for if it were, it would not be a resemblance relation that accounts for my thought of her. I do not need to recognize the picture as of my niece in order for the resemblance association to operate; it may well be a picture of someone else, but as long as what I see in the picture, for example, the contour of the face, color and shape of the hair, nose, eyes, etc., resembles my niece, a resemblance association can be produced in the imagination.

9 In Book One of the Treatise, Hume usually speaks of natural relations and associations as follows: when a particular impression occurs, a certain idea appears in the imagination in virtue of being related to the prior impression in a certain way. Hence, an association is such that an idea is produced in the imagination on the presence of either an impression or an idea (which can be either of memory or of imagination) in accordance with the associative principles. For this reason, associations are here attributed to the imagination, an idea-producing faculty. However, the scope of associations is broadened in Book Two to include associations with impressions of reflection.

10 What ‘objects’ amount to for Hume is controversial. Whether objects of ideas consist in objects represented in the content of ideas or in extramental objects should not make any difference to my reading here. I believe Hume thinks that ideas are about something. Hence, insofar as it is agreed that ideas are always about something for Hume, it does not matter, for my purposes, what this something amounts to for Hume. This something is what I am referring to as an ‘object.’ Hence, making a relation a feature of ‘objects’ rather than ‘ideas,’ I am not taking relations to be ‘objective’ in the sense that they are ‘real’ features of the external world. They may be regarded as ‘objective’ only in the sense that they are features of ‘objects’ of our perceptions, in contrast to ‘subjective’ as if they are created by the mind.

11 To say that a spatial relation between the sun in L.A. and my niece is experienced should not necessarily be taken to mean that an impression of the sun in L.A. and that of my niece themselves occur in the spatial relation, for example, spatially next to each other. To suppose so is to attribute the so-called sense-data theory of perceptions to Hume, and whether Hume holds such a view or not is a question beyond the scope of this paper. The point here is that a spatial relation is immediately experienced along with the relata in the first place, and what actually are experienced to be related — whether impressions of those relata themselves are experienced to be spatially contiguous — does not make any difference to the fact that the spatial relation is immediately experienced between the sun and my niece.

12 This difference may be due to a resemblance relation being an intrinsic relation as opposed to an extrinsic relation like the other two relations. Since a resemblance relation obtains only on the basis of the specific natures of the related ideas, if we understand Hume's perceptions as imagistic, a resemblance relation can be said to hold between my idea-image of my niece and impression-image of the picture. There is no difference between face-images, which are ideas, and objects of ideas, which are faces. However, since resemblance, contiguity, and causation are three ‘qualities’ of the same kind of relation (i.e., natural relation), it would be odd if they didn't operate in the same manner. Hence, it is very likely that Hume is sloppy in describing a resemblance relation.

13 An Enquiry concerning Human Understanding, Section 3, para. 3.

14 Alan Hausman, ‘Hume's Theory of Relations,’ Nous 1 (August 1967), 256-9; Norman Kemp-Smith, The Philosophy of David Hume: A Critical Study of Its Origins and Central Doctrines (London: Macmillan 1941), 246-8. They both acknowledge that relations that produce associations in the mind are holding between ‘objects’ and not between perceptions understood as mental items.

15 The distinction between conscious recognition of relations that involves cognitive operations of some sort and the mere presence of relations in the content of experience is an important one, which corresponds to Hume's distinction between philosophical and natural relations.

16 T 1.3.2.5-9; 1.3.6.2-16; SBN 75-7; 87-94.

17 How about a resemblance association? I admit that resemblance may be somewhat different from other two types of association in that objects of ideas that are associated on the basis of a resemblance relation need not be experienced together with a resemblance relation prior to the associative operation. It is probably because among the three natural relations, the resemblance relation is the only ‘intrinsic’ relation, and the other two are ‘extrinsic’ relations.

18 Again, a ‘perception’ here should not be understood as one where the contiguity relation is discerned and perceived as such.

19 I owe my readings of Hume's account of abstract ideas and how Hume could apply the associative mechanism involved in distinctions of reason to discernment of different relations to Don Garrett and David Owen respectively. In explaining that ‘distinctions of reason’ do not violate Hume's Separability Principle, Garrett, following Hume's own statement that ‘to remove this difficulty we must have recourse to the foregoing explication of abstract ideas’ (T 1.1.7.18; SBN 25), attempts to show that one and the same perception can represent more than one quality by being associated with what Garrett calls ‘revival sets’ of resembling perceptions; Cognition and Commitment in Hume's Philosophy (New York, NY: Oxford University Press 1997), 24, 62-4. Applying these accounts of abstract ideas and distinction of reason, Owen explains in one of the footnotes in his Hume's Reason (New York, NY: Oxford University Press 1999) that different relation may be discerned in one and the same perception when it is associated with different revival sets; see p. 106.

20 Hume explains this point as follows: ‘When we wou’d consider only the figure of the globe of white marble, we form in reality an idea both of the figure and colour, but tacitly carry our eye to its resemblance with the globe of black marble: And in the same manner, when we wou'd consider its colour only, we turn our view to its resemblance with the cube of white marble’ (T 1.1.7.18; SBN 25).

21 Phenomenologically speaking, this account may seem quite implausible since we do not go through different ideas to associate an idea with appropriate ones when having an idea of a particular relation. Hume seems to be aware of this point, as he states that ‘[a]fter a little more practice of this kind, [that is, comparing a globe of black marble and a cube of white with a globe of white marble] we begin to distinguish the figure from the colour… and view them in different aspects, according to the resemblance,’ and ‘[w]hen we wou’d consider only the figure of the globe of white marble, we…tacitly carry our eye to its resemblance with the globe of black marble … . By this means we accompany our ideas with a kind of reflexion, of which custom renders us, in a great measure, insensible’ (T 1.1.7.18; SBN 25; my emphasis). Hume seems to be saying here that we wouldn't be able to discern and distinguish a relation in the first instance of the occurrence of an idea, but we need some ‘practice,’ that is, the associative mechanism comes to be set in the mind only after some repeated occurrence of the resembling ideas in a particular respect, and this association is rendered ‘insensible’ in the mind so that it is not phenomenally experienced by the mind.

22 There is still a problem here: a set of ideas for ‘smaller than’ would be identical to a set for the relation ‘bigger than.’ Hence, Hume's associative mechanism seems to be inadequate to distinguish some relations (as pointed out by an anonymous referee). Hume might be able to solve this problem by appealing to the notion of an ordered pair: a complex idea of a tennis ball being smaller than a basketball is not just a mere collection of an idea of a tennis ball and that of a basketball, but rather those constituent ideas are ordered in a particular way, and so are all the other constituent ideas in the relevant set. However, he does not speak of such a pair of ideas in a complex idea at all in the Treatise; hence, the problem still remains. This may show the limitation of Hume's reduction of the mind to a mere bundle of perceptions. Nonetheless, as defective as it may be, the associative mechanism is his only explanatory principle that could be invoked to account for various mental ‘operations.’ Accordingly, Hume would have to concede the implications of this account, which will be discussed in the next paragraph.

23 Here again, ‘experience’ of a resemblance relation should be understood in a noncognitive way such that the relation is immediately present in the content of experience and is not apprehended or recognized as such.

24 This should not be understood to imply that ‘the color redness’ is a common feature shared by the apple and the car, as Hume himself denied at T note 5; SBN 637. In this example, the red of the apple is an individual particular shade of color and so is the red of the car. They just phenomenally resemble each other so that they are associated on the basis of that resemblance, which does not mean that they share a common quality, ‘redness,’ as if it were present in each impression. What is real here is a particular shade of color in the impression of the apple and another shade of color in that of the car, and they are two distinct ‘reds.’ As a particular quality, a red in the impression of the apple is a real part of the apple, and so is a red in the impression of the car, both of which are already present in experience prior to the associative activity of the imagination.

25 Let's take my present visual experience, which Hume would regard as a complex impression: roughly, there are books, a glass, a phone, pens, a computer, and a mouse on the desk. They are standing in particular spatial relations to one another; a book is to the left of, and a mouse is to the right of, the computer; five books are piled up on top of each other; the glass is above the mouse and pens are sitting next to the glass; and these objects are all on the desk. The spatial relations like ‘is to the right of,’ ‘is above,’ ‘is next to,’ and ‘is on’ are all present as part of my visual experience, that is, my complex impression, as much as the objects so related. They are all ‘immediately present to the senses’ as Hume puts it. Those relations are given in impressions to be discovered, and this discovery requires the associative operation in the imagination described above. Hume seems to think that we are not aware of such an operation in our experience since ‘custom renders us, in a great measure, insensible’ of it (T 1.1.7.18; SBN 25).

26 The distinction in question here is not a ‘distinction of reason.’ The notion of distinction that pertains to complexity of perceptions is a ‘real’ distinction that answers to the Separability principle. An impression of a brown rectangle is a complex impression because multiple impressions of brown points can be distinguished and are thus separable, not because the color brown and the rectangular shape are ‘distinguishable.’ The latter distinction is only a distinction of reason that does not entail that what are distinguished in that sense are separable. Hence, there are two senses of ‘distinguishability’ in Hume: a proper sense of distinguishability in which perceptions of two distinguishable objects/qualities can be separated in that they can exist separately, and a sense of distinguishability in distinctions of reason in which perceptions of two distinguishable qualities are not separable because they are identical. The latter case of distinguishability should not be taken as a counter-example to the Separability Principle.

27 Of course, the Separability Principle alone does not make distinguishable perceptions separate and independent existences; it only states that distinguishable perceptions are separable. Hume in fact introduces another principle, the Conceivability Principle, to arrive at the independent existences of perceptions, which I am going to discuss below.

28 The point I am arguing for here may be similar to one Weinberg makes in his book, Abstraction, Relation, and Induction (Madison, WI: University of Wisconsin Press 1965), 114-16. He argues that relations for Hume are either distinct from the related objects or distinguishable and thus separable from impressions so related, which would be incompatible with Hume's view that complex impressions can be decomposed into simple constituents. Weinberg seems to think that relations understood in either way would make impressions inseparable.

29 In the Appendix to the Treatise, Hume admits that he cannot renounce ‘that perceptions are independent existences,’ although he finds that it presents a problem for his account of personal identity in Book One of the Treatise.

30 James, William The Principles of Psychology (New York, NY: Dover Publication 1950), vol. 1, 245.Google Scholar

31 Ibid., 353.