SUO: Thoughts and judgments
John wrote:
> This was a hot topic in the late 19th century, when people like
> Peirce and Frege were trying to get rid of "psychologism" in logic.
> Frege was only half successful, since he continued to use words
> like "Gedanke" (thought) and "Urteil" (judgment).
John, Frege's success in cleansing logic of psychologism surely shouldn't
be evaluated on the basis of the words that he used, but in terms of what
he intended by those words. I agree that "Gedanke" was a poor choice of
terminology because of its mentalistic connotations, but it is clear from
Frege's writings that what he meant by a Gedanke was something objective
and mind-independent, roughly, the content of a declarative sentence, the
proposition it expresses. As to "Urteil", there is a definite -- but
inessential -- redolence of psychologism in Frege's writings. Frege was
getting at the difference between a sentence per se and the use of that
sentence to say something, for it is only when a sentence is so used that
logic comes into play. There is *nothing* inherently psychologistic about
that, but Frege's exposition of the idea does have psychologistic
overtones in spots, esp where he speaks of judgment as an "act" of some
sort, which suggests a sort of inward nod that accompanies an assertion.
However, I think this was just part of the birth pangs of nascent proof
theory. Nowadays the point is pretty much moot. The use of a sentence in
a context, formal or informal, is simply *taken* as a use of that sentence
to say (or assume) something unless otherwise qualified.
Bottom line (if I may :-): There is nothing essentially psychologistic
in the *content* of Frege's ideas of "Gedanke" and "Urteil".
Regards,
-chris