There is an interesting article by Tyler Burge in the NY Times philosophy blog called “A Real Science of Mind” that I happen to disgree with vehemently. He basically claims that representationalism is the only game in town when it comes to explaining visual perception. In fact, he doesn’t even hint at the fact that representationalism is but one theory, and one supported by philosophically ambiguous explanations of what it means to actually “represent” something. Indeed, he says:
Explanation in perceptual psychology is a sub-type of task-focused explanation. What makes it distinctively psychological is that it uses notions like representational accuracy, a specific type of correlation…Why are explanations in terms of representational accuracy needed? They explain perceptual constancies…Visual perception is getting the environment right — seeing it, representing it accurately…Perceptual psychology explains how perceptual states that represent environmental properties are formed.
Now, it seems to me that Burge has massively begged the question against nonrepresentational explanations of low-level visual perception.
In making this claim, I put myself in a precarious position. One of the main points of Burge’s article is that vision science is a highly developed and “mathematically rigorous” science. Burge is insistent that vision science is on solid explanatory ground and I have no intention of challenging the mountain of empirical evidence gathered by orthodox representational visual science. No, the question is not about the facts, but rather, about the interpretation of the facts. It is my claim that representationalism is but one way of interpreting the empirical facts gathered by orthodox visual science.
My claim goes as follows: talk about the visual creature “accurately representing” the environment can be replaced, without losing any explanatory power, by talk of “discriminating information” in the environment. Some would say this is merely a matter of semantics, and in a way they would be right. But when it comes to philosophical explanations of visual perception, semantics are of the utmost importance. But why bother with this semantic triviality between “representation” and “discrimination”? Aren’t they the same thing? In a way, yes. But, as William Ramsey has argued in his important book Representation Reconsidered, this theoretical equivalency is actually the result of orthodox visual science moving away from classic forms of representationalism. For when a visual scientist claims that the organism “accurately” represents a feature of the environment in perception, all the explanatory work is being done by the neural workhorse that is the brain. And, naturally, this explanation is ultimately cashed out in physiological terms, against Burge’s claim that visual science is truly representational.
It is my contention that talk of “differentiation” or “discrimination” is just as psychological as talk of “representation”, but discrimination is more ontologically coherent. Take the example of a hungry primate perceiving a juicy red strawberry. Orthodox visual science would say that in successfully perceiving the strawberry the primate must have accurately represented the red strawberry as a red strawberry, (and not, say, as a purple poisonberry). This is the classic representationalist explanation. On my view, it would be more philosophically parsimonious to say that in successfully perceiving the strawberry, the primate discriminated the strawberry from out of the ambient array of energy surrounding the strawberry. Another way of putting it would be that in perceiving the red strawberry the primate attended to the information specific to the features of the strawberry that were relevant to its internal needs, namely, hunger.
On this account, the primate can be said to perceive the red strawberry as nutritious, not as a strawberry. Notice how this is starkly different from the representationalist interpretation. For the representationalist, the primate’s perception of the strawberry is cashed out in terms of how accurately the internal representation is in comparison to the objective features of the strawberry. If the primate represents the strawberry as being red, and the strawberry really is red, then the primate’s perception of the strawberry is said to be “accurate”, and thus successful. It is then said that the brain consults the representation when forming its intentions to act. Orthodox visual theory is thus committed to what some philosophers have called the sense-represent-plan–act model. The primate receives proximal sense-data, tries to form an accurate representation of distal stimulus, consults the representation to form a plan, and then executes a motor command to pluck the strawberry and bring it into its mouth.
On my interpretation, we can eliminate the “represent” and “plan” stages and replace it with a sensorimotor model. On this account, the task of the brain is to discriminate the meaningful information already in the environment by attending to it. Neurally speaking, the discrimination supervenes upon the neural patterns of activity. So how is this different from the representationalist story? Because unlike Burge, I think the behavioral nature of discriminatory perception is actually a plus, not a downside (and of course, behavioral explanations are a kind of psychological explanation unless we beg the question against behaviorism). So we shouldn’t expect visual neuroscience to engage in representational theorization when the proper explanatory level of description is behavioral, not representational. I have never seen a representational theory that avoided the homunculus problem without merely collapsing into descriptions of the behavior of neurons.
And for good reason. Although Burge claims that representation is well understood by visual science, he is only half-right. Representation is well understood if by that we mean that we understand the neural underpinning and physiological correlations of the representation. But as William Ramsey has argued, this is precisely the point. Orthodox visual science has never actually successfully explained how a representation actually functions as a representation, as opposed to being a merely physiological mediator in a long chain of neural activity that ultimately leads to effective motor behavior.
So while Burge is perfectly right to say that “neuralbabble” is nonexplanatory on the psychological level, I believe he is mistaken when he claims that representationalism offers a philosophically rigorous interpretative framework that explains the phenomena at hand. Burge recognizes this when he talks about “generic representations” that apply so widely to any causal correlation as to no longer being explanatorily useful in cognitive science. To make representation explanatorily worthwhile, he introduces the notion of “accuracy”. But as I attempted to explain above, there is an alternative interpretation of accuracy available that focuses on the accurate perception of an affordance. But, crucially, the accurate perception of an affordance is entirely different than the accurate representation of an objective feature. This is because the affordance is more directly tied into the motivational circuits and can thus undercut the “represent” and “plan” stages of the sense-represent-plan-act model and jump right into the scientifically respectable arena of “sensation” and “action”. Hence, sensorimotor models of visual perception. The notion of accurately representing objective features of the environment is replaced by the accurate discrimination of information specific to invariant properties of objects which are themselves specific to affordances (opportunities for behavior). Perceiving the strawberry then becomes a matter of attending to those features of the strawberry which either past experience or innate knowledge has taught to be relevant to homeostatic needs.
Hence, we can account for the normative or “psychological” component of perception (its possible success or failure) in terms of how well the organism is capable of detecting information specific to properties that are themselves specific to affordances. And this offers us a path towards a “real science of mind”. Why? Because affordance perception is directly tied into those sensorimotor causal pathways that have been so successfully studied by orthodox visual science. And it does this without invoking a notion of one thing somehow “standing in for” something else.
Now, my representational critics will respond by saying that the discrimination of information specific to affordances is no more understood than is the notion of accurately representing the environment. Point well taken. But it is my contention that orthodox visual science has been talking about discrimination all along. So I really don’t see myself as being a “revolutionary”. I contend that we could go into almost every single visual science article and change “represents” with “discriminates” without losing any explanatory value. In fact, I think this semantical change would actually enhance the explanatory power of visual science precisely because “discrimination” is more ontologically tractable insofar as it doesn’t make a sharp distinction between the “merely mechanical” sensation of a bacterium and the “cognitive” perceptual capacities of “representing creatures”. One could say that my theory offers a “flat ontology” wherein all lifeforms are said to share in the capacity for discrimination of information and reactivity in direct response to that discrimination. Accordingly, my interpretation is immediately amenable with the advances being made in evolutionary biology.
Moreover, and most importantly for my purposes, the rejection of representationalism for an explanation of basic visual perception would leave room for those phenomena that truly deserve a representational explanation: human symbolic cognition. Indeed, in rejecting representationalism for the explanation of basic visual perception I do not reject all representational explanations like Anthony Chemero does. I thus think, following Clark and Toribio, that some phenomena are “representation hungry”, while others aren’t. Following Gibson, I do not think that basic visual perception as shared by most animals on this planet is representation hungry. What I do think absolutely requires a representational explanation is the symbolic and linguistic cognition of humans. For the referential system that is language absolutely requires an explanation of how one thing (a linguistic symbol) could “stand in for” something else. For example, the word “strawberry” cognitively stands in for a real strawberry. Now, I’m not claiming to have a complete theory worked out about symbolic cognition. But I think significant progress in the mind sciences would be made if we all recognized this demarcation between the nonrepresentational, sensorimotor cognition we share with nonhuman animals and the representational, symbolic cognition seemingly unique to humans.
Minds and Brains 