Recent themes in the philosophy of perception

I spent most of last weekend at a University of Warwick workshop on Perception, Consciousness and Reference. The workshop featured some of the key players in current debates about perceptual experience and knowledge, including John Campbell, Tim Crane, Barry Stroud, and Charles Travis, alongside Warwick regulars such as Bill Brewer, Quassim Cassam, Naomi Eilan and Matt Soteriou.

Rather than rehearsing the papers and arguments that were presented here, I thought it might be more useful and interesting to try to summarise some of the main themes that emerged from the workshop, many of which will form part of my own research in this area over the coming months. (I apologise in advance for the sketchiness and generality of these remarks, which are intended to give an overview rather than a detailed analysis of  these complex and difficult issues.)

‘Epistemic’ and ‘non-epistemic’ perception

First up is the relation between so-called ‘epistemic’ and ‘non-epistemic’ perception, which is something of much local interest at Warwick. I say ‘so-called’ because these terms, introduced by Warnock (1965) and popularised by Dretske (1969), more commonly refer to the relation between perception and belief, as opposed to knowledge, and so might more properly be called doxastic and non-doxastic perception, respectively. In any case, the main question at issue is whether perceptual experience per se—or what might be called ‘purely perceptual’ experience—is in some sense prior to or more basic than propositional belief and/or knowledge.

Now that’s a bit of a mouthful, so let’s break it down a little. Pretty much everyone agrees that there is a sense of ‘seeing’ (to take the most common example) that doesn’t require the subject to consciously notice or attend to what it is they see. This kind of ‘simple’ or ‘non-epistemic’ seeing is something that can be attributed to animals and infants, who can be said to ‘see’ objects and events of which they have, or are capable of having, no conception whatsoever. My pet fish, for example, is able to ‘see’ me sitting in front of the computer, in the relevant sense, despite her being unable to see that I am in front of the computer—a cognitive achievement which requires the ability to entertain propositional thought, and in particular the possession of the relevant concepts: computer, in front of, and so on.

It is a substantive question in the philosophy of perception whether such ‘non-epistemic’ seeing (in humans, at least) is in some sense conceptually prior to or more fundamental than ‘epistemic’ or propositional seeing. Some philosophers (notably John McDowell) claim that all perceptual experience is structured along conceptual lines, and potentially (in the case of McDowell’s earlier work) in propositional form. There are a host of delicate issues here, of which the relation between the epistemic and non-epistemic is just one, but there appears to be a growing consensus that there is some form of perceptually basic experience out of or upon which, and subject to the obtaining of various additional enabling conditions, belief and knowledge are constructed.

Whilst the epistemic/non-epistemic debate has a long and complex history, my sense is that these terms are too blunt to capture the range of distinctions that contemporary philosophy of perception is beginning to address. Such distinctions concern the nature (or existence) of perceptual representation, the relation between perceptual experience and practical abilities or capacities, and the cognitive architecture involved in processing perceptual experience, each of which I will consider in turn below.

Perceptual representation and content

Perhaps the main debate within contemporary philosophy of perception is between representational or ‘intentional’ theories of mind (RTM), and direct realist theories, such as Naïve Realism (NR). According to representationalism, the immediate objects of perceptual experience are not external objects, but mental representations, which stand in an external relation to external objects (i.e. the same representation may be present even in the absence of the relevant external objects). NR, on the other hand, is a disjunctive theory of perception that takes external objects to be (at least partially) constitutive of perceptual experience. On this view, the felt qualities of perceptual experience—redness, for example—are not mere by-products of the mind, but intrinsic properties of the everyday objects of experience. (This is a bit fast and loose, but you get the general idea.)

A further thesis which is often combined with NR is that perceptual experience is relational in character. Campbell and Brewer, for example, hold that such experience is a three-place relation between a subject, object and a third term whose properties (location, perspective, viewing conditions, etc.) jointly determine the phenomenal character of the experience (a circular object seen from here looks different to the same circle from here, and so on). As was brought out during the workshop, if the notion of a three-place relation is unappealing, this can instead be thought of as a two place relation with adverbial modifiers to capture the various aspects of the third term, or ‘standpoint’.

Debates between the proponents of RTM and NR tend to turn on the ability (or otherwise) of each theory to answer traditional sceptical questions concerning knowledge of the external world (i.e. the Argument from Illusion). This is, however, a notoriously thorny issue in which it is difficult to see what could count as evidence for and against each point of view, often ending up in discussions about where the burden of proof lies. A more interesting challenge, however, arises from within the philosophy of mind itself. Charles Travis (amongst others), for example, argues that perceptual experiences have no intrinsic ‘face value’ or propositional content, and that such content is supplied by the operation of recognitional and rational capacities quite separate to the basic faculty of perception. Indeed, he takes the idea that ‘pure’ perceptual content has a complex semantic structure akin to thought and language to be a mistake, claiming instead that perceptual experiences are unified wholes which only become decomposed into concepts through the operation of our recognitional, conceptual and linguistic capacities.

This in turn raises the question of how such ‘pre-conceptual’ content (if content is the right word) relates to the fully conceptual content of thought. Travis takes the fundamental issue in the philosophy of perception to be not a solution to the Argument from Illusion, but to explain how it is possible for perceptual experience to bear upon the contents of thought—his own answer being that we should think of perceptual content as being ‘Fregean’ rather than ‘Kantian’ in nature; i.e. a pre-existing whole, rather than comprised or constructed through sensory intuition. Conversely, McDowell endorses the Kantian view that experience is structured by the rational faculties of the subject in such a way that there is no need to bridge any such divide between the ‘conceptual’ and ‘non-conceptual’ realms.

Perception, action and practical abilities

It is widely accepted that at some point, perception must ‘bottom out’ into a set of practical abilities. Enactive theories of perception stress the complex relation between perception and action, traditionally conceived of as ‘inputs’ and ‘outputs’, but which turn out to be much less straightforward (Hurley, for example, considers perception to be a function of the relation between input and output, rather than simply of sensory input). Even on traditional theories of perception, however, recognitional and conceptual capacities occupy an important role that may be impossible to explain at the purely personal level, and which must instead be explained in terms of the operation of certain primitive interactions or sub-personal relations to the surrounding environment.

The empirical study of these practical abilities provides considerable grist for the philosophical mill. Workshop participants cited detailed and interesting studies on the functioning of attention, including our ability to single out and attend to distinct or groups of objects and their features, and the relative ease with which we are able to track the movement of multiple objects across our visual field. One gets the sense that such empirical work is slowly chipping away at some of the philosophical mysteries of perception, such as how it is possible for us to refer to objects under different modes of presentation, or to relate the non-conceptual content of perceptual experience to conceptual modes of representation or thought.

Of course, such studies still need to be given the correct gloss in order to be of much philosophical value, since the relevant distinctions are often obscured by researchers’ interest in the mechanistic or information processing implications of the data, as opposed to their philosophical significance. Nevertheless, it is important not to underestimate the value of the empirical research in this area, if only in giving clues about the kind of structures and processes that underpin perceptual and other cognitive abilities. By itself, this kind of data may be unable to resolve many of the central philosophical debates, but it can serve to inform and guide them in a way that is beneficial to philosophical enquiry. Just as the work of Descartes, Hume and Reid was influenced by the science of their day, so should our philosophical investigations into perception and perceptual consciousness take on board and provide interpretations of scientific findings, which serve as a touchstone—though not necessarily the arbiter—of philosophical debate.

And so ends my whistle-stop tour of the philosophy of perception. The nature and existence of perceptual content, the perceptual relation, and the structure of the cognitive architecture connecting perceptual experience, thought and action: three themes that I’m sure I’ll be spending a lot of time on in the coming weeks and months. I’ll keep you posted.