[FOM] Re: On physical Church-Turing Thesis

Eric Baum ebaum at fastmail.fm
Sun Feb 15 14:11:46 EST 2004

Warren D. Smith wrote two relevant papers. In the first,
if I recall correctly, he showed that for n bodies interacting
under Newtonian gravity, he could construct an orbit that
was not simulable by a Turing machine, although if he added
in some relativistic effects, the Church-Turing thesis held

In the second, he showed the Church-Turing thesis is true in
nonrelativistic quantum mechanics with sufficiently nice potentials.

Church's thesis meets the n-body problem:

Church's thesis meets quantum mechanics:



Also, my new book "What is Thought?", from MIT Press
gives a model that explains how mind is the execution 
of an evolved computer program, addressing aspects of 
thought such as understanding, meaning, creativity, 
language, reasoning, learning, and consciousness. 
The model is motivated by and consistent with extensive 
data from a variety of fields, and makes empirical 
predictions. The arguments are based on some principles
from computer science theory, particularly the recent 
formalizations of Occam's razor, but all background is 
pedagically reviewed so that the book should be readable 
by intelligent science readers from a variety of backgrounds. 
As part of this pedagogy, Chapter 2 reviews Turing's case 
that a Turing machine can simulate the brain.

For more information see:


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