Wednesday, February 09, 2005

Methodology of Philosophy of Perception

I notice a methodological issue that is common to most philosophy of perception. When one attempts to analyse perception he will typically take one of two apparent routes in doing so. Either he will assume knowledge of how perception works or he will assume knowledge of what we percieve and proceed to explain what is not assumed. One who assumes how perception works will use this to explain what we percieve and one who assumes knowledge of what we percieve will use this to explain how perception works.

For example, James J. Gibson, in his essay "A Theory of Direct Visual Perception", assumes what we percieve are real external objects. Assuming this he proceeds to explain how perception works and concludes that we have direct visual perception.

On the other hand one could for instance assume the nature of the human eye and brain as how perception works. Then from there he could proceed to explain what one percieves as external objects that set our perceptual mechanism in motion.

Either way it seems as if one must assume knowledge of one aspect of perception in an attempt to explain the other aspect. We must know something about perception in order to talk about it. So what do we actually know about the nature of perception? Do we know how we percieve, what we percieve, or neither? In an attempt to avoid begging the question about such matters it seems important to avoid assuming anything we don't yet know for certain about perception. It seems we ought to attempt to get at our most basic intuitions about the nature of perception.

I have been doing some thinking and it seems very intuitive that our perceptions are caused by something. If we have learned anything from Descartes it is that we must not be naive realists and assume that our perceptions are caused by the actual objects that are presumably 'represented' in our perceptions. But even Descartes acknowledges that these perceptions come from somewhere. If not from corresponding external objects then they come from something else, possibly an evil demon. Let's assume our perceptions are being cause by an evil demon. Even if this is true the phenomenal character of the perceptions would remain the same. It should not be assumed that the objects of our perceptions are the actual causes.

On this account it seems like we ought to call dreams perceptions since the phenomenal character of dream-perceptions are strikingly similar to 'awake'-perceptions. For me it is intuitive to say we are percieving when we are dreaming.


Is the phenomenal character of perception all we really know about the nature of perception? Well we know that perceptions are certainly caused by something, assuming something cannot come from nothing. But can we get anywhere about how perception works and what the causes of our perceptions are from this starting point? I think there are some very interesting routes one could take but I don't think merely assuming knowledge of either will get us anywhere but into an informal fallacy. Unfortunately a lot of philosophers of perception, espescially physicalists, seem to be taking the latter route. It may be a very hard place to start but we ought to at least be honest about it. Can a direct realist start from this point and get anywhere?


At 2:43 PM, February 12, 2005, Blogger Clayton said...

There is a lot of interesting material here. As a mad dog naive realist, however, I have to take issue with the claim that Descartes has provided us with any reason to think that naive realism is an unacceptable account of perception.

First, when you say 'it is intuitive that our perceptions are caused by something', I'm not sure what you are getting at. It seems that as a matter of empirical fact one could not have a conscious perceptual experience without something happening in the brain and the eye, but beyond that, it isn't clear that it is part of the concept of perceptual experience that we should accept the claim that a perceptual experience is simply a conscious episode contingently connected with an external object that has a representational content. It looks like the direct realist can grant that there are causal enabling conditions without buying into this idea that perceptual experience is something that can be 'produced' in the absence of an external object. That is not to deny that a BIV could be conscious, it is to deny that the BIV perceives what we do and that there is more to an experience than what you regard as phenomenal character.

Second, I'm not sure that we should call dreams perceptions--not, at least if you are a representationalist. The crucial difference between dreams and perceptual experiences proper is that only perceptual experiences could 'turn out' to have been veridical. Novels cannot turn out to have been a correct representation of anything because of their aim (Novels aren't inaccurate histories). Similarly, dreams do not appear to admit of veridicality either. This simply isn't a dimension by which we could evaluate dreams but some think that perceptual experiences themselves can be veridical or not.

You might say that there are lucid dreams that lead us to form beliefs about the external world, but note that the standard view of perceptual experience is that there is a distinction between two sorts of perceptual error: misjudgment and non-veridicality.

Third, I don't know what is motivating your scepticism concerning naive realism, but here is a sketch of an argument that (a) naive realism is correct; (b) the essential nature of perceptual experience is not exhausted by its general, phenomenal character (i.e., that which is shared by all and only the indistinguishable conscious episodes).

Think about perceptual demonstrative judgments such as 'That cup is hot'. What is the semantic value of 'that cup'? On the view of demonstratives defended by Kaplan, it is the cup itself. Had there been a different cup or no cup at all, a different proposition would be expressed. It seems that the role of perceptual experience is to put someone in a position to make such a judgment and if there was nothing more to experience than its phenomenal profile, perceptual demonstratives wouldn't have the semantic value we intuitively take them to have.

This last claim requires us to show that the proper account of perceptual demonstrative judgments cannot be given in terms of, say, conceiving of an object as the cause of an inwardly identifiable sensation. Two points suggest this demonstration is possible. First, we do not conceive of external worldly objects as theoretical entities which we would if we conceived of them as causes of some item which we are immediately aware of. Second, it seems that there are fewer open epistemic possibilities than the causal-descriptivist account of perceptual demonstratives would have us believe. Suppose I hold out a pen directly in front of me and looking at it realize that:

(1) This pen is blue.

If the perceptual demonstrative in (1) were analyzed in terms of something like:

(1a) The cause of this experience is blue.

Then it could turn out that this judgment is correct if my experience were caused by a martian made pen and experience-machine located 5000 miles away that is blue. This state of affairs is not one under which what I'm thinking when I utter (1) is true.

If you start with a conception of perceptual experience according to which the nature of the experience is nothing more than its phenomenal profile, you may well end up with a theory apart from direct realism. If, however, you focus on the judgments perception enables us to make and the semantics of perceptual demonstratives, something like direct realism looks far more attractive. I think this is why I'm sympathetic with A.D. Smith's claim that our choices when it comes to perception is really limited to direct realism or idealism, there is no third way.

At 6:15 PM, February 15, 2005, Blogger Andrew said...

What I'm looking for is a primitive definition of perception. It seems you have already established perception as being necessarily tied to sense-perception. You say:
"It seems that as a matter of empirical fact one could not have a conscious perceptual experience without something happening in the brain and the eye..."

This only follows if we already have a conception of how perception, i.e. sense perception, works. This only follows if we already assume some sort of epistemological realism.

It is concievable that we are being decieved by an evil demon and our perceptions of external things are not of actual independently existing things. Now...if this were the case would we still call the phenomenal experience 'perception' or would we need to call it something else since we already have assigned an essential feature to 'perception' that seems to be missing here, i.e. the brain and the eye?

I would assume that we would still want to call this mental experience 'perception' even if we had neither brains or eyes. This is why I make the claim that the only essential feature of perception is the phenomenal character.

Concerning your argument for naive realism, I don't think we can argue from what we believe our perceptual demonstratives to be expressing to ontology. This theory of perceptual demonstratives assumes the existence of the actual objects. The fact that we believe this is how our language works does not prove the existence of external objects that causally correspond to our perceptions. This was my point about naive realists begging the question.

Don't get me wrong...I do believe that epistemological realism is tenable. What I'm attempting to show is what is actually essential to our intuitive conception of perception. If we would call both phenomenal cases(evil demon and realism) perception then the only thing both cases have in common is their phenomenal character.

After we achieve the priviledge of some sort of realism we may then describe the inner workings of sense perception. My point is merely about the essential nature of perception.

I hope I did justice in representing your points.

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