Turing in fact dismisses the question in the famous letter. The Turing test isn't proposed as a test of whether machines can "think" but a test of whether they can imitate a person.
Turing considered the question of whether machines could think as being "too meaningless to deserve discussion".
Turing considered the question of whether machines could think as being "too meaningless to deserve discussion".
http://books.google.com/books?id=CEMYUU_HFMAC&pg=PA317&lpg=P...
Also
http://plato.stanford.edu/entries/turing-test/
Sorry this links quote Turing, I couldn't find the original source.