Ignore the part about the hoax.
It’s Swamp Mary Season here at Brain Hammer. Starting very soon, I’ll be serializing my new paper, “Swamp Mary Semantics: A Case for Physicalism Without Gaps.” But before jumping into that, I here offer a précis of the paper that it’s a sequel to, “Swamp Mary’s Revenge: Deviant Phenomenal Knowledge and Physicalism,” forthcoming in Philosophical Studies.
Swamp Mary is intrinsically physically identical to Jackson’s Mary after Mary has seen red. Mary knows what it’s like to have experiences of red. Swamp Mary has popped into existence, swamp style, without ever having a mental state with a red quale. But by being physically intrinsically identical to Mary, Swamp Mary has phenomenal knowledge in spite of their extrinsic differences. Swamp Mary knows what it’s like.
Some physicalists say this spells trouble for antiphysicalists. Some antiphysicalists say that they can embrace the possibility of Swamp Mary without any problems, since the possibility of Swamp Mary is consistent with denying that pre-release Mary can deduce the phenomenal facts from the physical facts.
I present two lines of argument against such antiphysicalists: The Psychosemantic Argument and the Factivity Argument.
The Psychosemantic Argument
If Swamp Mary has phenomenal knowledge, there must be some psychosemantic account of how a state of her constitutes a representation of the relevant phenomenal facts. There are four general approaches to psychosemantics: 1. Quotation, 2. Actual Cause, 3. Descriptive-isomorphism, and 4. Nomological. Approaches 1, 2, &3 are unavailable to the targeted antiphysicalists for the following respective reasons: (1), since Swamp Mary is stipulated to lack red qualia her concepts are not quotations of them, (2) for similar reasons, a red quale cannot have actually caused her concepts, (3) since antiphysicalists hold a red quale to be an ontological simple, it cannot be represented via the structural features essential to Descriptive-isomorphism. This leaves Nomological as the most promising psychosemantic approach for the antiphysicalist who would embrace Swamp Mary. But a problem that arises is that the requisite antiphysical psych-physical laws are arguably unknowable. And if the antiphysicalist dodges this problem by insisting that the laws don’t need to be knowable, then they are left especially vulnerable to the factivity argument.
The Factivity Argument
Let “D” stand for a massive conjunction exhaustively describing, in an exclusively physical vocabulary, the total current state of a deviant. Let “Q” stand for what it’s like to see red, a proposition of the form What it’s like to see red is such-and-such. Let “KQ” be the application of an epistemic modal operator to “Q” so that “KQ” is red as “It is known that Q”. Let “–>” be, at a minimum, an implication operator exhibiting transititvity. I will interpret it as material implication for now and will address a bit later whether it needs some other interpretation for the argument to adequately target Nondeducibility. Let “Deducibility” be the negation of the antiphysicalists’s Nondeducibility claim (that phenomenal facts are nondeducible from physical facts). The factivity argument, then, is as follows.
P1. D –> KQ
P2. KQ –> Q
C1. D –> Q
The most promising line of response for the antiphysicalist to respond to the factivity argument is to claim that pre-release Mary cannot, via deduction, get herself into a state that has as its content, Q. But this is to maintain a psychosemantic asymmetry between pre-release Mary (“pre-Mary”) and Swamp Mary. What psychosemantics can account for this asymmetry? Both Quotation and Actual-cause are out of the question, since they both inapplicable to pre-Mary and Swamp Mary. And the ontological simplicity of qualia continues to make Descriptive-isomorphism unavailable to the targeted antiphysicalists. All that’s left, then, is Nomological. And here it’s hard to see that the necessary asymmetry between pre-Mary and Swamp Mary can be maintained. Since pre-Mary is nomologically “locked on” to every physical property, and Swamp Mary is nomologically locked on to the relevant phenomenal property, there seems to be no bar to pre-Mary’s psychosemantically “piggy backing” on these nomological chains linking to a red quale that pre-Mary has never experienced. Swamp Mary may thus be used to secure reference to an unobservable much in the way that typically happens with scientific instruments and unobservables like electrons and radio waves.