Godel's theorem is consistent with the computationalist hypothesis. Ro
ger Penrose, however, claims to prove that Godel's theorem implies tha
t human thought cannot be mechanized. We review his arguments and show
how they are flawed. Penrose's arguments depend crucially on ambiguit
ies between precise and imprecise senses of key terms. We show that th
ese ambiguities cause the Godel/Turing diagonalization argument to lea
d from apparently intuitive claims about human abilities to paradoxica
l or highly idiosyncratic conclusions, and conclude that any similar a
rgument will also fail in the same ways. (C) 1998 Published by Elsevie
r B.V. All rights reserved.