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April 26, 2008
Common sense before science: the concept of "perception"
Recently I was happy to encounter an essay by Olli Lagerspatz, "Studying Perception," in the latest edition of the journal Philosophy (v. 83, April 2008, pp. 193-211). Its conclusion dovetails with some central conclusions of my dissertation work, and some of its details would help enrich my argument. I want to say a few things about it.
I argued in my dissertation that "naturalized epistemology" is essentially skeptical in nature. Quine concedes the basic anti-foundationalist criticisms of modern philosophy. Rather than trying to answer them, he offers a pragmatist's consolation: we don't need to worry about the logical justification of our beliefs, we need only try to understand how our beliefs allow us to cope with our experience.
I also argue that the only way to oppose Quineans is to grapple directly with the skeptical concerns that appear to make pragmatism the default. Quine himself thinks that many skeptical doubts arise from new scientific discoveries. Whereas he suggests that we can ease our doubt by considering the pragmatic value of our beliefs, I suggest that these skeptical worries arise from scientific discoveries only when insufficient attention is paid to the wider scientific context, and only given the uncritical acceptance of certain pre-scientific philosophic assumptions.
So my view is that while considering new scientific research can at best help clear up certain philosophic confusions, it is not the basis for new philosophy. Philosophy is an autonomous discipline, and one must accept one philosophical assumption or another before embarking on scientific research. Incidentally, this does not imply that philosophy is a priori or simply a matter of "conceptual analysis." It may well be that philosophic knowledge derives from empirical knowlege that is simply more basic and less specialized than scientific empirical knowledge.
Lagerspatz seems to agree with me. He suggests that empirical research in, for example, psychology, presupposes the acceptance of common sense ("folk") psychological concepts which guide the research. For example:
First, the scientist identifies a particular instance of perception on a common-sense basis. Someone knocks at the door and we hear it. Afterwards, there is an investigation of acoustic and physiological processes involved in this event. But the event has already been carved out of a larger whole and defined as a specific event. This is something we do because we understand what is relevant in it. And this gives rise to the task that the neurobiologist sets herself. We can ask questions about relevant processes because there is consensus about what it (roughly) means to say that a person hears something.
Like my approach, Lagerspatz uses this perspective to clear up skeptical confusions that arise from scientific discoveries. Consider his response to Antonio Damasio's contention that because perception involves internal physiological processing, that therefore the objects of perception must be internal (rather than external physical objects):
But that does not lend support to the claim that all you can perceive is constructed images. The quoted passages indeed start with a description that takes perception for granted. You are not imagining, remembering or hallucinating the landscape outside your window. This gives us the distinction between what Damasio calls ‘perceptual’ and ‘recalled’ images.8 But further down in the quote, the description implies you have noway of knowing that the initial description is true, as all these images are just constructions of your brain. This collapses the initial distinction between perception and hallucination....Yet the argument as a whole rests on the initial description that takes perception to be both possible and distinct from hallucination. It exploits our tacit commitment to what it moves on to deny.
In other words, no discoveries about the nature of perception are going to tell us that perception is not importantly different from hallucination--and it would not be importantly different if its objects were internal images rather than external objects. No research will show this, because scientists studying perception are already studying a physical process they assume to be different from the physical process involved in hallucination.
(I should note, incidentally, that this polemical move of showing how some philosophical arguments rely on common sense concepts but then empty them of meaning is underexplored and worthy of attention from the perspective of informal logic.)
Lagerspatz's approach also has important implications for the philosophy of mind. He considers the contemporary use of the concept "representation," a concept often used to describe the internal objects of perception. There may be a role for the concept, but it should not be used in a way that denies that we already know what perception is or what its objects are:
To say that one thing represents another is perhaps to say that the one is made to stand proxy for the other; or perhaps, that someone is employing it in order to convey an idea of the other thing, or to find out something about it. The traces represent something to the detective and to the neurobiologist. Thus it is very natural for the neurobiologist to say that the monkey’s primary visual cortex contained a representation. She [the neurobiologist] may use the trace to derive information about what the monkey was looking at."It may (to repeat: may) then be useful to speak of representations in the brain. But we also need to see why this should be. Clearly not all traces of causal influences on the brain will be called representations. Brain damage is not called a representation of the thing that hit the patient on the head. In the experiment just cited, the neurobiologist looks for a likeness in the brain. She also has an idea of where to look, namely in the part of the brain previously identified as one connected with vision. Visual likenesses accidentally found somewhere else in the brain or elsewhere in the animal’s body would have to be explained in some other way.
So perhaps the neurobiologist may speak of patterns of neural activation as "representations," in which case it would be obvious that mental representations are themselves neurological properties. But his overall point here has a further important implication even for questions about eliminativism or reductionism vs. commonsense realism about the mental:
Neurobiological descriptions of perception do not reduce mental events to physiological processes. In fact they cannot do so, because the phenomena they describe are themselves individuated on the basis of mental,11 not physiological criteria. Thus the method itself excludes reduction.12 In sum, the neurobiologist explains physiological data in terms of perception, not the other way around.13 She expands our knowledge of the unknown, namely the role of certain physiological changes, by relating it to what is known, namely perception.
Lagerspatz makes the above point a little too quickly, before he has commented on the sense in which "representations" may be said to be neurological. What is especially clear is that if our ability to identify mental "representations" presupposes our ability to distinguish perceptual conscious awareness from, say, patterns resulting from a brain imagery, then nothing about the physical nature of these "representations" can lead us to a Churchland-style eliminativism. Whatever is true about patterns of neural stimulation, we also know that we are perceptually conscious of the world and have real knowledge and beliefs about it (we could not specify any patterns if we did not presuppose this).
Arguing against reductionism about the mental is a little trickier. The reductionist can concede that of course we are conscious and have beliefs, but argue that conscious or belief states are themselves neurological states. To argue that the mental does not reduce to the physical simply because the relevant phenomena are "themselves individuated on the basis of the mental" would beg the question, because the reductionist could concede the latter point, and simply insist that the mental basis for our original individuation is itself a neurological state (even if we don't originally know that).
I think there is another route to Lagerspatz' desired conclusion, one that takes a cue from his own strategy. It has to do with identifying the mentalistic presuppositions behind even the concepts of the physical. But I won't go into that now.
Posted by Ben at April 26, 2008 09:44 PM