How are we to think about the nature of colour given the conjunction of the natural view and subject relativity, and the explanation offered in terms of the simple metaphysical picture? Earlier I suggested that it presents us with two key questions:
1. How can we make sense of qualities’ being out there in the environment and yet also determined in part by the subject?
2. What does this entail for other qualities of objects that do not seem to be subject- relative, and indeed for the objects themselves?
I have already noted that one broad theory of colour is aimed precisely at answering the first question. This is relationalism about colour, which holds that colours are
“constituted in terms of some relation between (inter alia) objects and perceivers” (Cohen 2004: 452). The most widespread form of relationalism is dispositionalism, whereby an
object’s being red is identified with its disposition to look red. The relevant disposition is typically explicated in causal terms, so that a disposition to look red is explained as a disposition to cause experiences as of redness. Formulated in this way, the dispositional account clearly conflicts with my defence of the natural view via the simple metaphysical picture, since the latter denies that experiences are caused by their objects; indeed, it denies that there are experiences in any substantial sense.
A non-causal account of an object’s being disposed to look red looks no more
plausible: if it is not a disposition to cause an experience as of redness then it is hard to see what other options remain (surely not a disposition to change in such a way as to become red). Intuitively, when we see an object’s colour, we do not see it as doing anything – rather we see it simply being coloured. According to the natural view, the way an object looks is just a matter of how things are with the object and its surroundings (the conditions of lighting, its position within the perspective of the subject, etc.).78 From the discussion
of physical illusions we can appreciate that there might be various ways for an object to look red – for us to see it in red light or through red-tinted spectacles, for example – but the paradigm kind of case would be one in which the viewing conditions are favourable and the object is red. To look red in such a case is for the object seen to be red.
A related worry about the application of the dispositional account in the context of the natural view is that the dispositional account of colour arguably fails to locate colour ‘out there’ in the right way. As noted earlier, it is implicit in the natural view that the various perceptible qualities of worldly objects are ‘on a par’ in perceptual experience: it is the object itself and its various qualities that simply feature as the constituents of
phenomenology. The tomato’s redness is seen in the same way as its roundness – just by being there, qualifying the tomato itself. Equating colours with dispositions, meanwhile, potentially opens up the primary/secondary quality or objective/subjective distinction alluded to in the second question above. Certain ‘primary’ qualities of objects are accessible to vision, shape being the obvious example. To see an object’s shape is presumably not to see an object’s disposition to look round, say; it is just to see its
roundness. We could assert this consistently with diverse theories of perception, including
78 We should note also that ‘looks’ is potentially ambiguous between phenomenal, comparative and epistemic readings so that, for example, the reflective surface of a wooden table in bright sunlight might look (phenomenally) almost white, but simultaneously look (epistemically) like it is brown (see Dretske 2000). In the current context, ‘looks’ is perhaps most appropriately taken to have its phenomenal sense.
those that postulate sense-data or qualia, but it is clearly essential to the natural view. After all, according to the natural view, it is the object itself and its qualities that constitute the experience’s phenomenology.
Thus, one reason to reject the dispositional view of colour is that it would seem to leave colours ‘out there’ in a rather different sense from the sense in which so-called primary qualities are out there. The latter are paradigmatic examples of ‘objective’ qualities of worldly object – qualities specifiable using methods available to any subject and without essential reference to how they appear perceptually to subjects. According to the natural view it is just these qualities themselves that contribute constitutively to the phenomenology of experience. Colours (and other ‘secondary’ qualities like taste and sound) are likewise supposed to contribute constitutively to phenomenology in the same way, as qualities inhering in the objects themselves. Dispositional accounts, however, leave colour rather more on the ‘subject side’ than this suggests. This may force them to admit two different uses of ‘colour’: on the one hand to denote the object’s disposition (or the categorical property underlying this disposition) and, on the other hand, to denote the phenomenal quality that the object is disposed to produce. Trying to collapse the two into a single sense might seem doomed to failure.
If dispositionalism seems unsuited to underpin the natural view, subject relativity nonetheless seems to entail some sort of relationalism about colour. After all, it does indeed appear that an object’s colour is constituted by the relations between that object and the perceiving subject. But if dispositionalism is not the way to flesh this out, how should we go about it? Is there a way to reconcile subject relativity, and so relationalism, with the natural view’s insistence that colours, etc., are straightforwardly ‘out there’?
I will argue that the answer is ‘yes’, but that doing so will extract a high price in terms of our commitment to realism and certain customary assumptions about the metaphysical structure of the world. It will be obvious that an affirmative answer will necessitate some sort of claim for the ‘mind-dependence’ of worldly objects or qualities. Nonetheless, I will show that we can recast such ‘mind-dependence’ in terms of a broadly physicalist ontology that eschews talk of ‘minds’ altogether. The ontology will prove simple – indeed, monistic – and although it is controversial, it has some independent support both philosophically and empirically.
This metaphysical account will occupy the following chapter. For now, in concluding this discussion of perceptual variation, I will sketch out how we get there by conjoining the natural view and subject relativity. Again, the key bridge between the two theses is the simple metaphysical picture of experience. Recall that what it is for an object or quality to be a constituent of an experience is explicated via the simple metaphysical picture in terms of its occupying a certain place in the causal process that is the object’s being perceived by the subject. Now let us recast the claim that colours are subject-relative as the claim that they are experience-dependent, i.e. their nature is determined at least in part by the nature of the perceptual experience in which they are presented. Since the simple metaphysical picture identifies the experience with the process, the experience-dependence of colours becomes the claim that colours are determined by the perceptual processes in which they participate (as qualities inhering in objects).
This of course inverts our customary understanding of the relationship between objects and the processes in which they participate. We would normally think of processes as being constituted by – built out of, to put it crudely – the various objects that participate in them. Constitution here is supposed to be allied to a form of determination, so that a given object has its nature determined by the antecedent nature of its constituents. There may be other forms of determination at play, such as causal determination, but the relevant
determination relation here is precisely the constitutive one. Central to the claim about constitutive determination is just this notion of metaphysical priority: given any object divisible into parts, the nature of those parts is metaphysically prior to, and thereby determines, the nature of the whole object.
We might call this customary metaphysical assumption bottom-up determination. By contrast, I am suggesting that applying the simple metaphysical picture of experience to cases of subject relativity or experience-dependence points to a converse picture we might call top-down determination. The claim, then, is that objects’ colours are subject-relative or experience-dependent because their nature is dependent on, and determined by, the nature of the larger (perceptual) process of which the objects are constituents. We could apply this theory to each of the three phenomena described above, namely simultaneous colour contrast, intersubjective variation in hue perception, and the structure of colour
space. In each case it is the nature of the whole perceptual process or relation between subject and object that determines the nature of the colour perceived.
Certainly, this view abandons the realism claim, i.e. that worldly objects exist and have their perceptible qualities independently of their being perceived. Consequently, it also abandons the explanatory virtue of naïve realism, by which the experience-
independent qualities of the object determine the phenomenology of experience. On the view I have presented the explanation goes at least partly in reverse; the properties of the scene are to be explained at least partly by reference to the whole perceptual process of which the scene is part. At this point, the view might also seem to risk incoherence. The simple metaphysical picture, after all, purports to explain experience in terms of a process that, implicitly, is defined over its (physical) constituents. Now, instead, it is claimed that the nature of the constituents is at least partly to be explained in terms of the process of which they are parts. So we seem to be seeking simultaneously to explain a process (experience) in terms of its constituents, and those constituents in terms of that same process. This, however, is an inevitable consequence of the notion of top-down determination defended here.
Some will further object that the view divests itself of its naivety as well as its realism, on the grounds that it is part of pre-philosophical common-sense that objects’ qualities are constitutively independent of our perceptions. I think there is a common-sense insight in the vicinity here, but that it has more to do with a grasp of our causal powers and their limits. So striking something affects things but merely looking at them does not. What is in at stake in the case of colour perception is not, however, a matter of our causal relations to worldly things and properties but our constitutive relations. And here I think there are no pre-philosophical intuitions to be had. The ‘naïvety’ to which the view is faithful is the sense that, in perceiving, we are simply presented with the world as it is (whether or not ‘how it is’ needs to be supplemented with ‘for us’).
I should, however, note the limitations of the claim supported by the evidence of the colour phenomena described so far. Taken by themselves, these phenomena entail only a limited rejection of the realism claim: they show at most that some qualities (specifically, the colours) of worldly objects are constituted partly by the perceptual processes in which they participate. They do not tell us whether the same should be said of other qualities of
perceived objects, although they do suggest by analogy how we might look for the subject- relativity of other qualities. I will leave it to the next, and final, chapter to consider the fuller metaphysical implications of subject-relativity for our view of objects’ primary qualities and for the objects themselves. Pressure to expand the scope of the top-down determination relation to objects and their primary qualities arises from the implicit requirement of the natural view that the various qualities of perceived objects, both ‘primary’ and ‘secondary’, have a certain parity as qualities genuinely out there, inhering in worldly objects. Cashing out what this parity amounts to will prove challenging, but it will ultimately require that worldly objects and their primary qualities too are experience- dependent insofar as they do not have their nature independently of the wider processes in which they participate.
Note also that although I have rejected the realism claim, the realism ruled out is of a restricted kind, framed in terms of the constitutive independence of perceived properties from their being perceived (their participating in the perceptual process). Set against this, the simple metaphysical picture presumes an ontology of physical processes of which objects with their properties are constituents. Indeed, it needn’t presume anything else – no especially ‘mental’ entities or properties except those that are defined over physical processes. As such, whereas the conjunction of the natural view and subject relativity (or experience-dependence) might seem to point to a sort of idealism in which objects and qualities are dependent on minds for their existence, the upshot will instead be a radical holism about the physical; one that results from reversing the normal assumption of ontological priority from parts to wholes. Neither idealism nor a notion of realism framed around ‘mind-independence’ is straightforwardly applicable to the view sketched here. I will say more about this in the next chapter.