Monday, April 27, 2020

On two knowledge arguments

There is a structural similarity between the main reasons for adopting the A-theory of time and the knowledge argument against physicalism. In both cases, it is claimed that there is some information that we know but which is left out of the reductive theory:

  1. I know that Alice is sitting now

and

  1. I know what it feels like to be sitting.

The first piece of knowledge cannot be derived from data about tenseless reality and the second cannot be derived from data about physical reality, or so it is claimed.

The similarity between the two arguments suggests that there should be a correlation between dualism and adherence to the A-theory of time: for if one is convinced by one argument, one is more likely to be convinced by the other, and if one is unconvinced by one, one is less likely to be convinced by the other. Speaking for myself, I am a B-theorist dualist, and while I am unconvinced by the time argument, I go back and forth on the mind one.

It is interesting, though, to see if we can go beyond superficial similarity. One way to do that is to see if the best responses to one of the arguments can generate plausible responses to the other.

The best response to the time argument seems to be the Kaplan story that “now” is a mere indexical, and that the content of “Alice is sitting now” is the proposition that Alice sitting is at t1 (if t1 is now), though the character or linguistic meaning of “Alice is sitting now” is something different from the character of “Alice is sitting at t1” (specifically, a character is a function from world-utterance pairs to propositions, and this character assigns to an utterance of “Alice is sitting now” at t in w the proposition that Alice is sitting at t).

Is there a similar story about mind argument? It’s not so clear to me. Perhaps a start would be to say that what makes me it true that I know what it feels like to be sitting is that:

  1. I know that sitting feels like this.

The physicalist analogue to the Kaplan story would then be that “Sitting feels like this” expresses the proposition that sitting feels like ϕ where ϕ is some physical state of affairs, but the character or linguistic meaning of “Sitting feels like this” and “Sitting feels like ϕ” are different. I don’t think this works, however. There are two ways of taking this approach:

  1. ϕ is a specific neural state that I have when I feel like I’m sitting (say, S-fibers firing)

or

  1. ϕ is a complex functional state that anything has when it feels like it’s sitting, a state implemented by different neural or other physical states in different beings.

On (a), we have an analogy to the time case, for we can take the character of “Sitting feels like this” to be a function that assigns to world-utterance pair the proposition that sitting feels like ϕ where ϕ is the physical state that is the feeling for the utterer in that world. But there is also a serious disanalogy: for in the time case, the B-theorist knows (or can claim to know) the character, since the B-theorist knows a priori the specific rule by which a referent is assigned to “now” at a world-utterance pair. But the physicalist does not know a priori the specific functional story which assigns a referent to “like this” at a world-utterance pair.

On (b), we have a disanalogy, since the character is constant: at every world-utterance pair, the same proposition is assigned as the content of “Sitting feels like this.”

Still, maybe there is still a fundamental analogy, in that the time case teaches us (if we accept the Kaplan story) that one proposition can be expressed by two sentences s1 and s2 such that it is correct to say “I know s1” but not correct to say “I know s2”. Thus, I know that I am sitting now but I don’t know that I am sitting at t1. And similarly, maybe, I know that sitting feels like this but I don’t know that sitting feels like ϕ.

What if we go the other way around, and see if the best answer to the mind argument helps with the time argument?

I guess what is generally thought to be the best answer to the mind argument is something like this: there is a conceptual difference between the “like this” of the feeling and the physical or functional state ϕ, but ontologically they are the same. And this seems very close to Michelle Beer’s defense of the B-theory.

Another prominent answer to the mind argument is to deny that the knowledge claim expresses factual knowledge, as opposed to something like know-how or imaginative mirroring. It seems to me that a know-how story could be told about the time argument: to know that Alice is sitting now is to have certain kinds of know-how concerning dealing with Alice’s sitting. The “imaginative mirroring” case might be harder.

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