I plan to write about (in)compatibility of the First-person knowledge and Content Externalism. As I understand, it is a worry of philosophers that the privileged status of the first-person knowledge seems to conflict with the main idea of content externalism. (So, e.g., when I sincerely utter, “water is wet,” I might not know that the content of my thinking was not:
that twater is wet. This appears to conflict with the idea that I must know the content of my own thinking.) Boghossian argues that the compatibility of the two will generate a very absurd result – i.e. if compatibilism is true, then we would be led to know
a priori certain facts about the world (which is clearly
a posteriori). And I want to block his argument. So here’s his argument.
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In his “What the Externalist Can Know
A Priori” (1998), Boghossian says that a compatibilist (of the First-person knowledge and Content Externalism) is in a position to argue the following:
(1) If I have the concept
water, then water exists.
(2) I have the concept
water.
Therefore,
(3) Water exists.
According to Boghossian, if content externalism were true, then (1) is knowable
a priori. Also, given the privileged status of the first-person, (2) is knowable
a priori. From these, it follows that (3) is knowable
a priori. [In arguing this, Boghossian holds that in a valid argument, the
a priori knowability of the premises guarantees the
a priori knowability of the conclusion.] However, (3) is clearly not knowable
a priori. Thus, there is something wrong in the compatibilism.
Boghossian considers two routes of rejecting this argument. First, an externalist can argue that (the existence of) water is not required in order for one to obtain the concept
water – thus (1) is not knowable
a priori. Second, the externalist can argue that although (the existence of) water is required for one to obtain the concept
water, that fact is not knowable
a priori.
Admittedly (at least by Boghossian), the second route seems more promising. In taking this route, I would like to suggest two ways to show that (1) is not knowable
a priori.
1. In order to know (1), I need to know (at least) both
(a) If I have a certain concept
x, then the object(s) correlated with
x (i.e. the extension of the term that expresses the concept
x) exist(s).
and
(b) Water is correlated with the concept
water.
Here, what I know
a priori is only (a). I do not know (b) a
priori; I know it
a posteriori. As a result, I do not know (1)
a priori.
2. It seems right to me to say that in holding content externalism, (the existence of) water is
presupposed for one to obtain the concept
water (rather than saying that in holding content externalism (the existence of) water is
required for one to obtain the concept
water).
If the existence of water is merely presupposed, then the fact that water exists does not follow from the fact that I have the concept water. In other words, the externalist would not be committed to the claim that water exists from his holding that he has the concept
water. Thus, an externalist need not take (1) as an
a priori truth. For him, (1) is plainly false.
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To be honest, I do not know if 2 is the right way to go. More specifically, I do not know:
(i) whether or not in holding content externalism, (the existence of) water is presupposed (rather than required) for one to obtain the concept
water,
and
(ii) whether or not the blue-colored sentence is correct,
and
(iii) if I am right about (i) and/or (ii), what would be the good strategies to show that (the existence of) water is merely presupposed (rather than required), and that the externalist would not be committed to the claim that water exists from his holding that he has the concept
water.
So I will appreciate greatly if you guys can share some thoughts. The comments about my (poor) wording would be of great help as well.