Slow Switch, JPK, and Validity

I've been working for a while on a paper defending this knowledge-first approach to doxastic justification:

JPK: S’s belief is justified iff S has a possible counterpart, alike to S in all relevant intrinsic respects, whose corresponding belief is knowledge.

One of the moves I often use in that paper involves an exploitation of content externalism. My belief is justified if my intrinsically identical counterpart's is knowledge -- but his knowledge needn't have the same content as my justified belief.

When I presented this paper in St Andrews last summer, Jessica Brown expressed the worry that the kind of externalism I was relying on made the view too liberal. She was worried that there'd be cases of intuitively unjustified beliefs, even though there were intrinsically identical counterparts who had knowledge. One possible family of such cases involves 'slow switch' subjects -- people who change in their external environments in a way that implies a change in content, without realizing it. Suppose someone commits the fallacy of equivocation because she has been slow-switched; won't JPK have the implication that her resultant belief is justified anyway? I think that JPK probably will have this implication. But I don't think it's intuitively the wrong one. Consider a case. This example is borrowed from Jessica's book.

Sally starts out a regular earth-person, who knows some stuff about aluminum, but not much detail about its chemical composition. She does know, however, that some of it is mined in Australia, so she says to herself:

(1) Aluminum is mined in Australia.

One night, unbeknownst to Sally, she is moved to Twin Earth, where there is no aluminum, but instead, some superficially similar stuff twaluminum. After a while there, Sally has thoughts about twaluminum. In particular, she comes to know that some of it is mined in the Soviet Union. This is the belief she expresses when she says to herself:

(2) Aluminum is mined in the Soviet Union.

She hasn't forgotten her previous knowledge, so she still knows (1). And she's unaware that "aluminum" in (1) refers to different stuff than does "aluminum" in (2). So she might well put these together and infer her way to a claim she'd express by:

(3) Something is mined in Australia and the Soviet Union.

Sally equivocates on "aluminum", because of her external environment. Intrinsically, she's just like her counterpart who stays on regular earth and comes to know that aluminum is mined in both places, and (validly) concludes that something is mined in both places. So JPK has it that Sally's conclusion, (3), expresses knowledge, even though it is the product of equivocation.

I think, however, that this is exactly the right result. It is intuitively plausible to suppose that Sally's appearances are misleading, but her belief is justified. This mean that invalid reasoning doesn't always interfere with the justification of beliefs. But that's what we should think about this case, independently of JPK.

I'd be interested to hear any thoughts from any readers, but especially answers to these:

(a) Do you agree that it is intuitive to describe Sally's conclusion (3) as justified?
(b) Do you see any other, more problematic implications for JPK that derive from slow-switch considerations?

Rationality and Fregean Content

I haven't been updating my blog since moving to UBC last fall, partly because I've been busy preparing new courses and grant applications and settling into a new city. (My two biggest professional bits of news over the last while, for anyone interested who hasn't already heard elsewhere, are that The Rules of Thought, my book with Ben Jarvis, is now under contract with OUP, and I'll be beginning an Assistant Professorship at UBC this summer.)

I'm now starting to shift back into research mode, however, and blog activity may come back up accordingly.

One of the philosophy books that has been on my 'to-read' list for a long time is Jessica Brown's Anti-Individualism and Knowledge; I've been interested in the relationship between mental content and epistemology for a while now. Of course if I'd been cleverer about it, I'd've read the book while I worked at St Andrews and spoke to Jessica regularly, but: better late than never.

Among the interesting things Jessica is up to in her book is an argument that Fregeanism about content is inconsistent with -- or at least, fits poorly with -- anti-individualism. This is the negation of one of the chapters of The Rules of Thought, so I wanted to attend especially to the argument. (Thanks to Sandy Goldberg for bringing this connection to my attention recently.)

One of Jessica's arguments boils down to this. (I'm looking at pp. 200-201.)

1. Fregean sense depends for its motivation on the transparency of sameness of mental content.


2. Anti-individualism is inconsistent with the transparency of sameness of mental content.


3. Therefore, if anti-individualism is true, then Fregean sense is unmotivated.

In defense of (1), Jessica suggests that, were it possible for a subject to be wrong about whether two token concepts express the same content, the failure to make logically valid inferences would be consistent with full rationality. Celeste is in a Frege case.

Celeste fails to make the simple valid inference ... since she does not realize that the relevant thought constituents have the same content and thus that the inference is valid. Further, she can come to the correct view only by using empirical information. On this view, her failure to make the simple valid inference does not impugn her rationality, for even a rational subject would fail to make a valid inference that she does not realize is valid.

Jessica suggests that Fregeanism is motivated by the possibility of rationally holding what would be according to non-Fregean views contradictory sets of beliefs, or rationally declining to infer according to what such views would say are logically valid inferences. I agree -- a central motivation for Fregeanism is to explain why there's nothing irrational about believing Hesperus to be F and believing Phosphorus not to be F. But why does this rely on the assumption of the transparency of sameness of content? Jessica says in the passage above that there is an alternate explanation available, if transparency is denied: one doesn't make what is in fact a logically valid inference because one doesn't realize that it is valid, and this is consistent with full rationality.

Jessica's argument seems to rely on this claim:

(Reflection) If a subject doesn't realize that an inference is valid, then she faces no rational pressure to make it.

But Reflection strikes me as a pretty dubious principle in generality. Suppose somebody is pretty dense, and fails to realize that modus tollens is a valid inference form, and so fails to realize that various instances of it are valid. She sits there and thinks if it has an even number, then it's red and it's not red, and finds herself with no inclination to infer it has no even number. Surely her ignorance doesn't excuse her rational failure. So Reflection is false in generality; so arguments that rely on Reflection are unsound. It looks to me like Jessica is relying on Reflection, so I think her argument is unsound.

That said, there is admittedly an intuitive difference between my dense character and Jessica's ignorant one -- Jessica's character's failure to infer in accordance with valid inferences would be corrected by suitable empirical information; mine presumably wouldn't. Could this motivate a weakening of Reflection to render Jessica's verdict while avoiding the problematic one? Maybe, but it looks to me like it'd end up pretty ad hoc. (One upshot of Timothy Williamson's work on apriority is that it's very difficult precisely to state the kinds of connections to empirical investigation that underwrite certain intuitions.)

The Fregean can say this: failure to infer according to logically valid inferences is a rational failure, whether or not the subject recognizes the inference as a logically valid one. This, combined with the intuitive verdicts (no rational failure) about Frege puzzle cases, implies Fregeanism, but does not require any thesis about the transparency of content. This seems to be to be the natural thing to say.

 

Edit: Aidan McGlynn tells me that John Campbell and Mark Sainsbury are on the record against (1) in Campbell's 'Is Sense Transparent?' and Sainsbury's is 'Fregean Sense' in his collection Departing From Frege. I'll be interested to read them.