FOM: Wittegenstein and Brouwer wtait at
Fri Feb 6 14:44:48 EST 1998

Torkel Franzen writes
>(i) there is much that is
>reminiscent of Brouwer in Wittgenstein's earlier writings, in
>particular in the Philosophical Grammar and the Philosophical Remarks,
>and (ii) according to contemporary sources, Brouwer made a considerable
>impression on Wittgenstein.

As for (i), I carefully referred only to _Philsophical Investigations_. There is good evidence that W changed his views about mathematics through the 30's. (See Steve Gerrard, ``Wittgenstein's philosophies of mathematics'' Synthese 87 (1991):125-142.)

2. Incidently, a good part of my grounds for thinking that W's views about mathematics, even in _PI_, were founded on ignorance is

§124. Š It [philosophy] leaves everythinbg as it is. It also leaves mathematics as it is Š.

It is hard in the face of this to think that W was consciously advocating a revisionist conception of mathematics. (And yet, even in _PI_ his opposition to set theory, as he understood it, is evident. E.g. see § 426 and, especially, Part II p.232 (XIV)

3. As for (ii), yes; and that is why I am puzzled. (I wasn't using `it puzzled me' in the English professors' sense of `it is false and I can't understand how anyone could be so thick as to believe it'.) True, the Feigl report concerns a lecture in 1929; but I see W's critique of rule following in his later writings as a development of Frege's critique of psychologism; and W certainly know of that in 1929. Even if he had not begun to think about rule following the psychologistic element in Brouwer's is very explicit (even though it is played down by later exponents of intuitionism).

Bill Tait

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