Boghossian-Style Incompatibilism (Part 2)

In my previous post I outline a reductio against compatibilism. However, I believe the compatibilist has good reason reject (R4) of the reductio. Underlying (R4) is the implicit assumption that a subject can only have privileged access to the fact that she is thinking some thought θ if she is able to distinguish it, from some other thought θ*, without consulting her environment. However, the compatibilist has good (independent) grounds to reject this assumption, and with it, (R4). For example, Falvey and Owens [1994] distinguish between ‘introspective knowledge of content’ and ‘introspective knowledge of comparative content’:

(*) An individual knows the contents of his occurrent thoughts and beliefs authoritatively and directly (that is, without relying on inferences from observation of his environment). Call this kind of knowledge introspective knowledge of content.

(**) With respect to any two of his thoughts or beliefs, and individual can know authoritatively and directly (that is, without relying on inferences from his observed environment) whether or not they have the same content. Call this kind of knowledge introspective knowledge of comparative content. (pp. 109-110. Italics theirs)

Clearly, C-externailism is incompatible with (**). However, Falvey and Owens maintain that (**) does not coincide with our everyday attributions of self-knowledge. To see this, they invite us to consider a well-known debate between Benson Mates and Alonzo Church. Mates and Church disagree on how the relationship between the following two propositions should be understood:

(i) Nobody doubts that whoever believes that Mary is a physician believes that Mary is a physician.

(ii) Nobody doubts that whoever believes that Mary is a physician believes that Mary is a doctor.

Mates [1952] takes himself to be expressing two different thoughts when he utters (i) and (ii), while Church [1954] believes that the thought he expresses by (i) and (ii) are the same. Each believes that the thought he expresses when he utters either of these sentences is the thought captured by the sentence in the public language, English. Moreover, both are proficient in English, and are familiar with all of the terms expressed in (i) and (ii). Presumably, each of them knows perfectly well the thought each sentence expresses. However, one of them must obviously be wrong. Which of the two is in error is irrelevant for our present purposes. The take-home point is that it would seem highly implausible to suppose that whoever is wrong is guilty of some sort of introspective failure.

This example intimates that one can, in a very ordinary sense, know that one is thinking the thought θ and not know whether or not one is thinking the thought θ* in thinking this very thought. Moreover, introspection is of no assistance to Mates and Churchland in attempting to settle this disagreement. Falvey and Owens [1994] summarises the upshot of the Mates-Churchland dispute:

To resolve the dispute between Mates and Church one does not need better inner eyes; one needs additional information about the world we live in, the nature of our linguistic practice, the semantic theories that best represent that practice, and so on. (p. 113)

Some of this information would admittedly be logico-philosophical in nature. However, it is also clear that no consensus could be reached between the two independent of a serious empirical investigation of linguistic practice. Thus, the fact that we have a priori knowledge of our thought contents does not entail that we must be able to discriminate between them without recourse to empirical observation. We may therefore consider (**) implausible, along with (R4).

Boghossian-Style Incompatibilism (Part 1)

Arguments against the compatibility of a priori self-knowledge and content externalism (henceforth, C-externalism) typically fall under one of two headings. First, there is the achievement problem, according to which C-externalism entails that a subject can only come to know the content of her thoughts by examining her environment, and the consequence problem, the charge that C-externalism (when combined with privileged self-knowledge) implies that a subject may have a priori knowledge of empirical facts about her environment.

I will begin with an examination of the achievement problem. Roughly, the achievement problem may be put as follows: C-externalist thought experiments seem to demonstrate that given an appropriate difference in the external world, there will be a difference in thought content, without this difference being reflected in any inner detectable manner. This seems to imply that one cannot tell, without consulting the external world, which of two thoughts one is entertaining, and hence one cannot be said to know what it is one believes or thinks. The intuition underlying a priori incompatibilism is typically illustrated via an appeal to Boghossian-style slow-switch scenarios.

Slow-switch Sue :
Imagine a subject, Sue, who was born and spent most of her life on Earth, where the word ‘tiger’ refers to the creature of the family and genus felidae panthera. However, at some point in the past Sue was secretly transported to Twin-Earth where there are no felidae panthera but only pligers, animals which are visually indistinguishable from felidae panthera but are of a different evolutionary heritage, family and genus. Moreover, Sue is ignorant of the relevant biological facts that distinguish tigers from pligers. Sue is at the zoo, looking at a familiar large striped mammal, and thinks a thought which she expresses with the utterance, ‘that tiger has stripes’. According to the C-externalist, whereas Sue formerly entertained tiger-thoughts, she is currently entertaining a pliger-thought. However, according to the incompatiblist, Sue would fail to notice the change in her environment or her thought contents. If we were to ask Sue whether her thoughts have changed in content after they have in fact done so, she would most likely say they have not. Sue could only know that her thought contents have changed by learning additional empirical facts about her environment. Thus, the incompatibilist concludes that Sue cannot distinguish a priori between the actual situation in which she thinks ‘that tiger has stripes’ and the alternative situation in which she lacks this thought. Thus, Sue’s actual belief that she thinks ‘that tiger has stripes’ fails to constitute an instance of a priori knowledge.

We may unpack the intuition illicited by the Slow-switch Sue example via the following reductio:

(S1) Sue knows, without consulting her environment, that she is entertaining the thought that tiger has stripes.
(S2) Sue knows, without consulting her environment, that C-externalism is true.
(S3) Given (S2), the thought Sue is now entertaining—the tiger-thought—is a different thought than the thought ‘that pliger has stripes’ (the thought she would have in a pliger-world).
(S4) Given (S1), Sue is in a position to know, without consulting her environment, that she is not thinking the thought ‘that pliger has stripes’.
(S5) Given (S1)-(S4), Sue is in a position to know, without consulting her environment, that she is not in a pliger world.
(S6) Intuitively, neither Sue nor anyone else can know that she is in a pliger world without consulting her environment.
(S7) Therefore, if C-externalism is true, Sue does not know, without consulting her environment, that she is entertaining the thought, ‘that tiger has stripes’.

The central intuition on which the above reductio hangs is (S6). I see no reason to question this intuition. To wit, it may be agreed on all sides that a subject can only ascertain that she is in a pliger world by consulting her environment. In my next post, I will limn a compatibilist reply that involves the rejection of (S4).

"Internalising" McDowell

In my previous post, I addressed the main methodological objection to my claim that McDowell is a J-internalist. In this post, I will attempt to address what I take to be the primary theoretical objection to this proposal.

But first, what textual evidence do I have for holding that McDowell is a J-internalist? Two of the more suggestive passages are as follows:

I agree…that we lose the point of invoking the space of reasons if we allow someone to possess a justification even if it is outside his reflective reach. [McDowell 1998b, p. 418]

And:

[O]ne’s epistemic standing on some question cannot intelligibly be constituted, even in part, by matters blankly external to how it is with one subjectively. For how could such matters be other than beyond one’s ken? And how could matters beyond one’s ken make any difference to one’s epistemic standing? ([McDowell 1998a] p. 390)

I interpret the locution ‘how it is with one subjectively’, as an umbrella term for the sorts of things that are typically taken to be internally available to one, such as one’s thoughts, beliefs etc. By McDowell’s lights the circle delineating what is subjectively available to one exhausts that which may serve as a justifier for one’s beliefs. When this idea is restated in the argot of possible worlds, we arrive at McDowellian J-internalism, (M-Int):

(M-Int) For all agents S1 and S2 and worlds W1 and W2, if S1 in W1 and S2 in W2 are identical in terms of how things are with them subjectively, then S1 and S2 are identical in all respects relevant to the justification of their beliefs.

Now the main theoretical objection to my proposal can be put as follows: McDowell could not possibly be a J-internalist since he subscribes to a type of content externalism (henceforth, C-externalism) and C-externalism entails the falsehood of J-internalism. This objection hardly seems surprising when we juxtapose the popular construal of J-internalism and C-externalism:

(J-Int) For all subjects S1 and S2 and worlds W1 and W2, if S1 in W1 and S2 in W2 are identical in the intrinsic properties on which their thoughts supervene, then S1 and S2 are identical in all respects relevant to the justification of their beliefs.

(C-Ext) There are subjects S1 and S2 and worlds W1 and W2, such that S1 in W1 and S2 in W2 have the same intrinsic properties but differ in the content of their thoughts.

There is a conflict between (J-Int) and (C-Ext) since the former requires all subjects who are identical in terms of their intrinsic properties to have the same justificatory properties, while the latter allows subjects with identical intrinsic properties to differ with regards to the justificatory properties of their beliefs. For example, consider two subjects, S1 and S2, who are identical in terms of their intrinsic properties, but occupy different external environments, W1 and W2, respectively. Suppose S1 and S2 both performed the following valid deduction:

(A) Water is a liquid.
(B) Water is potable.
(C) Therefore, water is a potable liquid.

According to (C-Ext), the thoughts expressed by sentences (A)—(C) are different for S1 and S2. This is because S1’s thoughts are individuated in terms of water while S2’s thoughts are individuated in terms of twater. The distinct pairs of thought that S1 and S2 express by (A) and (B) are relevant to the justification of the pair of beliefs they respectively express by (C). Consequently, S1 and S2 satisfy the antecedent of (J-Int), since ex hypothesi they are identical in terms of their intrinsic properties, but fail to satisfy the consequent—to wit, they differ in some respects relevant to the justification of their beliefs. Thus, if (C-Ext) is true, then (J-Int) must be false.

There is a strong temptation to assume that this line of argument also impugns (M-Int). But if we take seriously McDowell’s notion of object-dependent thought there is no obvious inconsistency between (M-Int) and (C-Ext). According to McDowell, how it is with one subjectively is in part constituted by objects in one’s environment. For instance, in the Twin Earth examples generated by (C-Ext), the object-dependent thoughts expressed by (A) and (B) in the foregoing deductive inference are different for S1 and S2. Hence, by McDowell’s lights, S1 and S2 fail to satisfy the antecedent of (M-Int) since S1 and S2 are not identical with regards to how things are with them subjectively. Thus, McDowell can, without contradiction, continue to hold to (M-Int) while subscribing to (C-Ext).


References:

McDowell, J. (1998a), ‘Criteria, Defeasibility, and Knowledge’, Meaning, Knowledge, and Reality, 369-94, London: Harvard University Press.

McDowell, J. (1998), ‘Knowledge By Hearsay’, Meaning, Knowledge, and Reality, 414-43, London: Harvard University Press.