Mark Hogarth
(Wolfson College, University of Cambridge)
Would You Please Stop Talking About the Church-Turing Thesis, Please

The new and flourishing field of unconventional computing (hypercomputing) has prompted some to question the alleged truth of Turing's thesis. I am prompted towards a more radical view. I maintain that what these exciting investigations reveal is that there is no such thing as an 'ideal computer', and consequently Turing's thesis, which in essence asserts the equation of this ideal computer with the Turing machine, should be seen as a pseudo-claim. I have no special brief to be rid of the ideal computer or the Church-Turing claim. Rather, my view stems directly from a new picture of computability, which itself is motivated by an analogy with the concept of geometry. This picture will be sketched.