P e r c e p t i o n • D e f i n e d

Q: What would you say is the most important thing to establish as a basis for explaining perception?

A: A definitive theory of representation. There are countless theories of perception, yet only one—and I should say that I have researched the field extensively—is based on a fully fledged theory of representation. Donald Brook, an art theorist working in Australia since the 1960’s, has developed a theory of representation that I think deserves to be much more widely recognised. His interest in the later work of Ludwig Wittgenstein, Gilbert Ryle and J. L. Austin led him to reject much Continental philosophy at a time when the influence of thinkers like Maurice Merleau-Ponty, Roland Barthes and Jacques Derrida was at its height. I suspect that this is in part responsible for the paucity of response to his work despite its fairly wide dissemination internationally.

Q: What do you see as the importance of Brook’s work?

A: Brook’s theories offer several vital critical distinctions and conceptual tools that help to explain a number of longstanding philosophical perplexities. His theory of representation in particular provides a thorough account of the ways that shared sensory fallibilities enable representational practices to emerge and develop. It also clarifies the difference between practices of efficacious substitution that are fundamental to nonverbal representation and practices of denotation or signification, which are not. By situating representation in an evolutionary context and by paying close attention to nonverbal procedures of representation, Brook has also fleshed out a powerful account of the emergence of language. Without wanting to sound grandiose, I think that his work offers important insights that have the potential to help significantly in the pursuit of a theory of consciousness. Moreover, without a theory of representation, the like of which is to be found in much of Brook’s work, I very much doubt that even the less daunting but nonetheless significant questions of perception will be settled any time soon.

Q: So I guess you'd recommend that readers wanting to follow this discussion should probably start by reading our last dialogue on the subject of representation.

A: That wouldn’t be a bad idea.

Q: So, on the basis of Brook’s work, how would you define perception?

A: Perception is an evolved form of responsiveness—a knowhow we might say—constituted by dispositions to represent the things with which we are causally engaged. It is an immediately available capacity to substitute one thing for another, because there are respects in which these things are sensorily indiscriminable from one anotherat least for members of a community of perceivers sharing similar sensory strengths and weaknesses.

Q: Could you explain what you mean by a disposition to represent?

A: I mean a behavioural pre-disposition or pre-conditioning to indicate, name, describe, draw, construct, mimic or select a matching, simulating or symbolizing object that is usefully substitutable for one or more things that are currently stimulating our senses.

Q: But surely the capacity to represent things is learned? Are you saying that perception only emerges as we become capable of drawing or describing things?

A: Drawing and describing are highly evolved skills that have only been available to humans in relatively recent evolutionary time, so no, I think the capacity to select a matching or simulating object relative to the originally encountered object is a more fundamental skill.

Q: Is this also a learned skill then?

A: We certainly get better at all forms of representation through practice but it may be the case that some rudimentary perceptual skills are genetically inherited. Simulating is a more plastic and manipulable practice than matching, although both are genetically inheritable.

Q: Does this mean that animals might also qualify as perceivers?

There's a great deal of evidence, particularly among social species, that animals communicate with one another in simple ways. Communication relies on representational practices, so yes, I think we have every reason to suppose that many animals qualify as perceivers.

Q: And insects?

A: To the extent that insects are capable of acts of communication, we have good reason to consider them as perceivers, yes.

Q: So, if a creature is not capable of representing anything in any shape or form, then you would say that it's not a perceiver?

A: That's right. But bear in mind that creatures may be capable of producing representations, despite the lack of overt evidence of their doing so that we would regard as persuasive.

Q: Then, how could we ever be sure they are perceivers?

A: Well we couldn't, but that's where neuroscience might help by developing ways to trigger and detect these causally influential dispositions to represent.

Q: What about things that we don’t perceive but that influence us anyway, things like UV light for instance?

A: Yes, there are many. Perception is really just the tip of an iceberg of sensory responsiveness. Our bodies are involved in countless ongoing sensorily mediated processes that are either completely inaccessible to perception or are only accessible when we turn our attention to them.

Q: Is all perception conscious then?

A: To be unconsciousness is to be incapable of perception, yes.

Q: What about dreaming?

A: Dreaming is an unconscious or semi-conscious state in which various dispositions to represent are triggered by ongoing brain activity of a sort that is largely or perhaps wholly uninfluenced by sensory input.

Q: So, dreaming would only qualify as a perceptual state if it involved sensory input, which it rarely if ever does?

A: That’s right.

Q: Psychologists often conduct experiments using optical illusions because these are thought to indicate something about perception. Can you shed any light on the perplexities of optical illusions?

A: This is something I have researched quite a lot recently. If we return to our previous discussion about practices of representation, we will find that many optical illusions exploit culturally acquired skills of image-recognition and simulation. In the 1960's, for example, several studies were undertaken to examine whether individuals living in different cultures were differentially susceptible to optical illusions. Individuals living in cultures where pictorial representations were rarely used—even otherwise literate cultures—were found to be unaffected by optical illusions. The perplexity created by many optical illusions is simply due to the fact that our biologically as well as culturally evolved skills enable us to represent what we see in two equally viable ways. Other optical illusions expose related fallibilities of colour or motion perception, some of which we have learnt to exploit through the use of filmmaking techniques and others of which we may perhaps find new ways to systematically exploit in representational terms in the future.

Q: So do you agree that optical illusions are deceptive because they lead us to make inaccurate judgements?

A: Apologies, but of all the misconceptions about perception, what you have just said is probably the most prevalent and the most obstructive to insight. Most optical illusions have nothing whatsoever to do with ratiocination or other forms of conceptual thought. Optical illusions exploit mistakes—or fallibilities—yes, but the fallibilities are on the level of sensory discrimination, not intellect. Knowing that we are looking at an illusion doesn’t make it any less illusory. And this is because neither our conceptual knowledge nor our ability to rationalise play any part in the underlying sensory discriminations that characterise perception. Our procedural knowledge, on the other hand—our knowledge of how to use representations—does have an influence on our perception, as I mentioned. Noticing what philosophers call “elusive appearances” or “vilibilia” is a non-conceptual knowhow that has developed through culture.

Q: Could you elaborate?

A: Sure. The fact that we are able to conceive of visibilia has been enabled by pictorial techniques that have been developed over thousands of years and that have found their most familiar apotheosis in the invention of photography. Indeed, only very recently has it become clear the degree to which our procedural knowledge and visual concepts are informed by culturally evolved skills of representation. Guy Deutsche’s 2011 book “Through the Language Glass” eloquently describes how people in simple cultures have no concept of blue but only develop the concept as a consequence of practices of pictorial representation and representationally informed language use.

Q: You often mention evolution. Do you have a theory of how perception, as contrasted with regular behavioural responsiveness, evolved?

A: I do. Practices of representation are social by their very nature and their evolution is undoubtedly the consequence of long histories of social coexistence amongst similarly sensorily endowed organisms. Organisms have evolved to respond to the environments in which they live, but in doing so they have also developed the capacity to respond to one another. The behaviour of other organisms has the capacity to provide valuable cues that, if responded to in the right way, could make the difference between survival and extinction. Similarly, the ability to respond to the behaviour of another individual by behaving likewise is the basis of mimicry, a skill we see widely in the animal world and one that I suspect is centrally implicated in the emergence of representational practices and the perceptual capacities that these practices enable.

Q: I'm not sure I understand. Surely these practices of representation are public, whereas perception is a mental process.

A: To an extent you’re right—perception is indeed a mental process but it would be a mistake, I think, to assume that representing practices are purely public. For an organism to deliberately produce a representation, even of the most basic kind, it must direct its actions by way of biological mechanisms, many of which are private. I suggest that these dispositions to produce publicly perceptible representations form the basis of what we know as perception.


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