It seems initially plausible to suppose that mental representation can be reduced to phenomenal character. That is, we all know that when we think about things we get into certain states of mind, and there is such a thing as what it's like to be in that state of mind. Now, when we think about things, we are representing the world as being in certain ways. It is tempting to suppose that this representing can be explained entirely in terms of the what-it's-like (phenomenal character).
According to naive forms of representative realism, this is because that phenomenal experience resembles the object. For instance, the experience of seeing a white paper has a certain characteristic - whiteness - which is like the whiteness of the paper. With the rise of modern philosophy and science, this view was rejected, and the primary/secondary qualities distinction was born. Empirical investigation showed that the whiteness of the paper was actually a disposition to reflect all visible wavelengths of light (approximately) equally. However, there is nothing in the subjective experience which reflects light. Thus color was classified as a 'secondary' quality. Secondary qualities are dispositions to cause ideas not resembling the quality itself. (Actually, exactly what secondary qualities are for, e.g., Locke is a difficult question, but his official definitions take this form - see EHU 2.8.10, 2.8.21.) Qualities like shape and size, however, are supposed to be real qualities in the things themselves which resemble our ideas.
This, however, won't work either - at least not as stated. For in what respect would my experience resemble the shape or size of the object? To resemble something is to share some property with it. However, no experience can share the shape or size of a physical object. For instance, my desk is about five feet long and rectangular. If the mind is physical it must be located in the brain. But nothing that resembled my desk in respect of being five feet long and rectangular could fit in my brain, which is much less than five feet long. If the mind is non-physical, then it is not extended at all, and so nothing in the mind has any shape or size. These sorts of considerations give rise to Berkeley's famous dictum "an idea can be like nothing but an idea."
The obvious response is to say that it's not the case that my idea of the desk is five feet long and rectangular - that's just goofy. Rather, my idea of the desk represents the desk as being five feet long and rectangular. But now how are we to succeed in our project of explaining representation in terms of phenomenal character? If there is nothing in the phenomenal character which is like an external object, how can it be in virtue of the phenomenal character of the experience that it is a representation of that object?
In the New Theory of Vision, Berkeley argued at length that visual ideas come to represent tangible objects by a learned association between the two: I learn that there are such and such connections between visible roundness and tangible roundness, and so whenever I see visible roundness I think of tangible roundness, automatically and by habit. In the Principles of Human Knowledge, Berkeley places tangible and other sensory ideas on the same level as visual ideas.
Suppose, then, that it is by our learning the connection between ideas and what they represent that our ideas come to represent things. This learning takes place by observing correlations. So infants start out with ideas that don't represent anything at all - all they have is the what-it's-like, the phenomenal character. Since their ideas are not representative, they can't think of or observe external objects, but only their own ideas. (It is only by means of ideas, we are supposing, that one can think of or observe anything.) So the connections they learn must be between one idea and another. It will follow that ideas can only represent other ideas. If this is so, then it is impossible to so much as think of, let alone perceive, mind-independent external objects. But we do in fact think of some sort of physical objects. So physical objects must not be mind-independent external objects but rather complexes of ideas. (If I am right in attributing this line of thought to Berkeley, it is not going to be easy to get the doctrine of notions off the ground, and if we can't get the doctrine of notions of the ground we won't be able to meaningfully affirm - let alone prove - the existence of God or other minds; I suspect that the solution to this problem is going to lie in the ideas of reflection, which I haven't discussed here.)
Now, there are basically two tactics for wriggling out of this argument: (1) denying the premise that mental representation is reducible to phenomenal character, or (2) developing an explanation of mental representation in terms of phenomenal character which does not depend on resemblance. (1) comes in two basic flavors: direct realism, and primtivism. According to direct realism, we perceive the objects themselves, not independent mental representations of them. This view has problems with misperceptions and it's also unclear what the best way of accounting for memory, imagination, etc. on this kind of view is. (But there is a vast literature on the subject, and I am not familiar with much of this literature; the solution may well be out there.) Primtivism takes representation as primitive. That is, that my idea of the desk represents the desk as five feet long and rectangular is a basic fact that cannot be given a more basic explanation. One thing to note about this view: if there is any sense to be made of the mind-body distinction (and there is), then mental representation, as the name suggests, falls on the mind side. So to take mental representation as primitive is to commit oneself to (at least) property dualism. Finally, (2) is exemplified by some forms of functionalism in the philosophy of mind: the mental state encodes certain data about the object and is used by the agent to interact with that object. It is in virtue of the total functioning of the system that the state counts as a representation of the object as being that way.
The argument is thus not inescapable, but it is certainly at least interesting.Posted by Kenny at March 27, 2010 12:37 PM
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