A formulation of the principle was given by
Stephen Wolfram in February 1985. In
Undecidability and Intractability in Theoretical Physics , Wolfram wrote that Wolfram states that such a principle would hold provided that physical systems have a finite density of information and that information can be transmitted only at a finite rate in a finite-dimensional space. Later in 1985,
David Deutsch stated the principle with respect to
finitary machines and processes. He observed that
classical physics, which makes use of the concept of
real numbers, cannot be simulated by a
Turing machine, which can only represent
computable reals. Deutsch proposed that
quantum computers may obey the principle, assuming that the laws of
quantum mechanics can completely describe every physical process. An earlier version of this thesis for classical computers was stated by Alan Turing's friend and student
Robin Gandy in 1980. A similar thesis was later stated by
Michael Freedman in an early review of
topological quantum computing with
Alexei Kitaev,
Michael J. Larsen, and
Zhenghan Wang, known as the Freedman–Church–Turing thesis: This thesis differs from the Church–Turing–Deutsch-Wolfram thesis insofar as it is a statement about computational complexity, and not computability. ==See also==