A philosopher walks into a bar and says to the
bartender, Ill just have a coke (perhaps because she agrees with
Thoreau: I would fain keep sober always; and there are infinite
degrees of drunkenness).
Lets assume she does want a coke, and that she knows she wants a
coke. (It is strange to say X knows shes in pain, but X knows
what she wants sounds normal to me.) By saying this, she brings it
about that the bartender also believes she wants a coke. At least,
that presumably is the immediate point of saying this.
However, she does not thereby make it possible for him to know, by the
same method she has followed, that she wants a coke. That is: she
doesnt prove to him that she wants a coke. Rather, she gets him to
accept this belief by virtue of her (apparent) authority (in this
case, the apparent authority vested in her by the legal system as
apparent owner of the money he assumes she will use to pay her tab).
Question: is this permissible for a philosopher?