Sunday, 8 June 2014

Perception Defined

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’ve researched this 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 disseminated, debated and applied than it has. 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 denotation or signification, which are by no means fundamental to nonverbal representation, and practices of efficacious substitution that are. 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.


Simon said...

Very inspiring - as usual... An interesting phenomenon might to be inter-species communication (species in the jungle ‘listening in to each other’s chatter’ - spotting predators early when the birds fall silent). Also: ‘Dumb’ representation (mimicry in insects, lock-and-key detection of molecules) leads evolutionarily to conscious representation (human language), which can again be mimicked by dumb processes (Turing test).

Jim Hamlyn said...

Wow Simon, that's a really important distinction you make there between "dumb representation" and "conscious representation". My theory is that the jump from dumb representation to conscious representation is the most important evolutionary leap that animals ever made - from mere purposeful behaviours to intentional actions.

William S said...

Re: Merleau-Ponty, every time I mention perception to anyone who teaches theory in art schools they say 'Ah – The Phenomenology of Perception.' I suspect this is because it's the only widely known book with perception in its title, and is felt to be the last word on the subject, though very much less often read than cited. It's within the continental tradition that has come to dominate all art thinking, as 'Critical Theory'. It's a strange book, dedicated to the thesis that understanding the physical pre-conditions of perception is not just unnecessary but actually very wrong. The book is an anti-science polemic.

William S said...

On a quick reading, Jim, I suspect our differences may revolve around definitions of 'concept', 'thought' and 'cognition', and other related terms and matters. Basically I think I'm counting as types of rational thought processes that you would not. I'll get back to it anyhow…

Jim Hamlyn said...

Thanks William, what a pleasure it is to read your analysis of MMP and his ruinous PoP (Phenomenology of Perception) philosophy. Much as we agree on many things I think our principal differences revolve around different conceptions of what constitutes representation. It is this that motivates my anti-intellectualism. If perception is a skill distinct from mere sensory receptiveness then we need to consider it in the context of other public skills that creatures exhibit. Skills of nonverbal representation are the most obvious contender. The anti-intentionalism (not to be confused with anti-intellectualism) of the Turn to Affect that Ruth Leys criticises is motivated by an impoverished understanding of representation. If these theorists abandoned the indefensible idea that representation is dependent on signification then they could develop a clear understanding of how intentions form through the mobilisation of dispositions to represent perceptually encountered things. Sorted.

William S said...

So, Jim, having just read what you have to say about optical illusions, where you distinguish between sensory discrimination and intellect, I have a question – not about illusions (yet) but about ordinary, successful i.e. reliable, vision. Would you class discriminating between a vertical line and a horizontal one as sensory or as intellectual? (It's not a loaded or trick question by the way. I haven't got a snappy comeback ready – it's just about defining our terms.)

Jim Hamlyn said...

Yes, sensory discrimination is a disposition to respond differentially to objects or attributes of different sorts. I draw a sharp line between sensory discrimination and the more sophisticated skill of distinguishing which is linguistically enabled and allows us to do all kinds of additional stuff.

William S said...

So, what's the answer with the line? Which is it?

Jim Hamlyn said...

It's sensory discrimination (not deciding). If it took conceptual thought to do such a simple thing, life would never have got started.

William S said...

Isn't deciding whether a thing is of one sort or another conceptual thought? Or, to put it another way, does making such a decision have to take long enough to notice you're doing it to count as conceptual thinking?

Jim Hamlyn said...

A decision takes the comparison of differing options and the execution of a judgement based on a projection of the most advantageous outcome. A disposition to respond is a tendency to do a certain thing in response to a certain stimulus. The difference in energy consumed alone is gigantic.
Of course, using language, you can do all kinds of subtle forms of distinguishing that are enabled by culturally acquired concepts which allow us to analyse what we see and make countless judgements.

William S said...

So, is distinguishing between a line that goes up and down and one that goes side to side 'conceptual thinking'?

Jim Hamlyn said...

All distinguishing is conceptual. All discrimination is sensory. Obviously you need to be able to sense something before you do any distinguishing about it but, and this is crucial, you don't need to be able to distinguish between one line and another in most cases to be able to behave intelligently in relation to them but you would need to be capable of discriminating between them by sensory means.
The difference between a horizontal fountain pen line and a horizontal ballpoint line would requires distinguishing aided obviously by sensory discrimination.
It might help if you could characterise, as simply as you can, what you mean when you say that an optic nerve "decides". I suspect that some pieces will fall into place just by reasoning that through.

William S said...

At the level I'm talking about a 'decision' would be this – one neuron fires if the line is horizontal, and another fires if it is vertical. So, ordinarily defined it is a type of decision, since there are two options, and one or other of those is the outcome. But it's also remote from any ordinary usage because we don't usually talk about neurons – we talk about sandwiches and shoes, and so on. The word makes some sense in this context, but there are problems – Can one, for example, make a decision and not know about it? Does that count? Generally we'd say no, but then allow some unconscious decisions (in therapy we will admit to them, for example). My question really is about your confident distinction between 'sensory' and 'intellectual'. The problems with 'decision' are not the same, but are similar in an important way to those affecting your 'distinguishing' and 'conceptual' and 'sensory' and other words.

Jim Hamlyn said...

When an infant pushes bricks through a sorting toy the toy doesn’t make a decision which blocks to let through, nonetheless the toy is predisposed to allow bricks of a certain kind through one hole and bricks of another kind through another hole. It's a filter.
I think we should avoid ascriptions of decision-execution unless we can provide evidence that this is the case. Decision-making is way up the evolutionary tree. We have more parsimonious terminology and if we don’t use it then we’re in danger of muddying the water with ascriptions of decision-making before we have even got to the more challenging question of how a creature could actually make a decision.

William S said...

You're urging care and caution about what we call things here, but 'All distinguishing is conceptual' is not cautious; and I don't think it's really right either. 'All discrimination is sensory' is even less cautious, and I can't think what you think it means even. Also that analogy with your son's sorting of blocks is a bad one – not because the toy is clever, but the toy is on its own. One cell isn't clever. There have to be others with which it has connections.

Jim Hamlyn said...

I wrote that "I" draw a sharp line between sensory discrimination and distinguishing. I didn't expect that this would be immediately obvious. I therefore also explained what I think constitutes discrimination ("a disposition to respond differentially to objects or attributes of different sorts") and what I think constitutes distinguishing: "linguistically enabled" concept formation.

William S said...

Back to Ryle – The Concept of Mind is not a book about brains, it's about minds. And 'Ryle's regress' points out the absurdity of believing that a thought must be preceded by a thought to think that thought, and that preceded by another, and so on. But he has nothing to say about the biological conditions for, or necessary precedents to, a thought. He has nothing to say about neural correlates (actually I don't think that term was around when Ryle wrote his book). There are, demonstrably, necessary biological antecedents to, for example, deciding between two things – and that's true whether it be abstract discernment (is it round or square?) or the expression of preferences (cheese or ham?).

Jim Hamlyn said...

You pick me up on the sorting block analogy but you miss the fact that in your own elaborated characterisation you needed two (not one) cell to do the deciding.You keep on making the same mistake in my view. You think that we need to map an engine molecule by molecule and causal influence after causal influence as if this will reveal what it is to drive a car. The reason I think Ryle had his head screwed on about this is because he focussed on what we do as a means to understand our concepts of mind. If he had spread the net a little wider rather than focussing entirely on language I suspect that he would be regarded as the person to have finally settled the question of consciousness.

William S said...

It works with one cell if it's deciding between being a thing – vertical, or blue for example – and not being that thing. In fact that's how it does work in a lot of cases. Apparently. But my main worry with what you're saying is that I don't think the definitions of these key terms you're using are really coming across. They need to be fuller, because to me it looks as if some things are being dismissed out of hand as types of 'conceptual thinking'. And that was your term to begin with, remember, so it warrants more attention. It seems to be key to what you're saying. Does it, for example. require consciousness? Does it take time to do? Those things would clearly differentiate it from a cellular stimuli sorting process in the retina, which is very very quick and does not, on its own, generally register in consciousness.

Jim Hamlyn said...

"Cellular sorting" - that's fine. Go with that. Drop deciding. You didn't like it in the first place anyway.

William S said...

Have another look at the post above where I discuss whether or not it's suitable to speak of deciding. It's not even a little bit like whether or not I 'like' it! Actually, to save you doing that – What I say there is that the process I have also called 'cellular sorting' is, in SOME ways, just like what we would ordinarily call deciding – and then again, in SOME other ways, not. My problem with some of your ideas is that you use, say 'intellect', as if we all knew what it is in this extra- ordinary context. So saying boldly that it is, or is not, a feature of perception makes no sense.

Jim Hamlyn said...

I was being facetious. But filters don’t make judgements, much as we might want to say that what they do has the appearance of judgement. The optic nerves of the human eye do not decide to be unresponsive to UV or infra red (or cheese for that matter). To say that what they do has SOME characteristics of deciding is already to concede that deciding is not precisely what they do. I’m happy to agree that “one neuron fires if the line is horizontal, and another fires if it is vertical.” That is the kind or parsimony that scientists would insist upon, but I’m not happy calling it deciding, and nor I imagine would most scientists. Deciding, as I have already said, requires the comparison of two or more options and the execution of a judgement based on a projection of the most advantageous outcome. Manifestly cells can’t do that.

William S said...

That's a very workable definition of 'deciding' for future use in this context – but you can't have thought that that's what everybody already means by it. Obviously they don't – especially not that part about an 'advantageous outcome'. You've added that yourself. The problem throughout is the assumption on your part that your own definitions of words, which are perfectly usable ones, but which are not the dictionary definitions and which are not in general nor in recognised academic/technical circulation, are correct and clear. This is certainly an area in which new coinage is required – the current uses for the word 'intellect' must be in flux, is a good example. But deciding on a definition just on your own and then insisting on it isn't the way ahead, because people aren't going to know what you mean. Especially if you get impatient with them for not already thinking what you've thought on your own. As to your last point – Why can't cells do that? Do you mean single cells can't do that? How many cells then? Or is it something else altogether? (Sorry – bit abrupt! Doing lots of things at the same time.)

Jim Hamlyn said...

That's fair criticism but since we are at the stage of clarifying our definitions I think this is inevitable at this stage of theorisation. I don't mean to be dogmatic and I hope that's not how it comes across. Many philosophers are very fond of new coinage and the arguments for this are compelling (ish). Nonetheless we have a lot of workable terms already that, with careful use or slight modification, can do a lot of important work. One of the reasons I admire the Ordinary Language philosophers is because they resisted new coinage because they recognised the power of extant concepts and the need to examine their use very carefully. You're right that I added the part about "advantageous outcome" but I don't think it in any way distorts the concept to say that in any decision we seek an outcome and the efficacy of the decision is dependent to a large degree upon our ability to conceive of what that outcome might be. It wouldn't be a decision otherwise.

William S said...

It's not a distortion; but then I didn't say that it was. Defending it against the charge that it's a distortion is actually a distortion though (because it implies I said it was). It's more like a codicil really. It narrows the scope of what we're permitted, by the terms of this exchange as you would have them, to call a decision, thus foreclosing any discussion of what is or is not a decision. You want to offer it as a working definition, not just assume that it is. It isn't. It could be, but it isn't now.

Jim Hamlyn said...

So, let's get this straight. Are you saying that my insistence that decisions necessarily involve skills of mind narrows the scope of what we are permitted? I can't disagree that any definition defines limits - that's what definitions are for. They set the parameters for coherent discussion. If you want to retain a wide usage of the word "decision" you will need to accept that the most common equivalent in ordinary language is: "To make up one's mind." Cells don't have minds.

William S said...


Jim Hamlyn said...

So, you don't think my definition of the word decision is "very workable" after all?

William S said...

You need to tell people that that's the definition you're using before you use it.

Jim Hamlyn said...

Ok, to make a decision is to make up one's mind. Things without minds can't make decisions. Are we settled on this first principle or is there anything else we need to establish at this stage?

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