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Thursday, May 6, 2010

Swamp Deviants, Part II

Peter Mandik sent me a draft of a paper in which he addresses one aspect of my criticism of Swamp Deviants. The issue, which I discussed here a couple of days ago (Deviant Phenomenal Knowledge) and elaborated upon earlier today (Can Swampkinds Be Deviants?), is this: Can a Swampkind have deviant phenomenal knowledge--that is, can they know what it is like to see red without first seeing, imagining, or hallucinating the color red?

A Swamp Deviant is a Swampkind who knows what it is like to see red without having ever seen, imagined, or hallucinated the color red. One objection to the idea of Swamp Deviants is the argument that Swampkinds cannot know anything at all, because they cannot have any intentional states. To have an intentional state which is about red, for example, you must have a causal history which connects your state to the color red. Knowledge supervenes over causal histories, and not simply over neurological states. Since Swampkinds have no causal histories at all, then a Swampkind cannot be born with knowledge of any sort. They could only learn what it is like to see red by having the right kind of experience. An experience that generates such knowledge is what I call an "earning experience."

Mandik argues that, if this objection to Swamp Deviants works, then it can work against the knowledge argument itself. According to the knowledge argument, Mary the super-scientist cannot learn what it is like to see red because she has no access to color experiences (other than experiences of black and white), even though she learns every scientific fact about colors from inside her monochromatic existence. Yet, according to the historicist, Mary's scientific knowledge of colors would have to be causally connected to redness. Thus, Mandik argues, we no longer have a reason to suppose that black-and-white Mary doesn't know what it is like to see red.

I think defenders of the knowledge argument have a response here. (Though I am no defender of the knowledge argument, as my previous posts make clear enough. See, for example, What Zombie Mary Knows.) They can claim that what the knowledge argument shows is that Mary must have the right kind of causal history before she can gain the right phenomenal knowledge. Yes, her scientific knowledge must be causally related to redness; but it is not causally related in the right way. I therefore do not think Swamp Deviants pose a serious threat to the knowledge argument.

In any case, I have another historicist argument which defenders of the knowledge argument could use against the possibility of Swamp Deviants. If phenomenal knowledge is propositional knowledge (as the knowledge argument requires), then it entails justified true beliefs. (This is generally accepted, even if justified true belief is not universally accepted as sufficient for propositional knowledge.) Thus, we should be able to talk about phenomenal beliefs. We could presumably also talk about true phenomenal beliefs which lack justification, and which therefore are not knowledge. What better than a Swampkind could exemplify this?

We could grant that a Swampkind is born with true, though unjustified, phenomenal beliefs. What supervenes over causal histories is not the belief itself, but only the justification for the belief. In this case, Swampkinds are not born with phenomenal knowledge. They are born with true phenomenal beliefs which await justification. There is an intuitively appealing idea that motivates this argument: The only thing that could justify a phenomenal belief is an earning experience. If this intuition is correct, then, by definition, a Swamp Deviant's phenomenal beliefs cannot be justified, and a Swamp Deviant cannot be a deviant at all. In short, if (1) phenomenal knowledge is propositional knowledge and (2) the only way to justify a phenomenal belief is with an earning experience, then (3) Swamp Deviants are logically impossible.

[Update, May 7, 2010: It occurs to me that the two premises in this last argument, if correct, establish the logical impossibility of deviants of any sort. But I am not convinced these premises are sound--more specifically, I am not convinced that phenomenal knowledge is propositional knowledge.]