It also influenced biology. DNA acts both as a genetic program, and (when being copied) as data. Although I haven't traced the history in detail, I suspect that our ideas about DNA's function owe a lot to computer science. John Von Neumann did a lot of the early work on computers, and he also produced a theoretical analysis of self-reproducing systems (in general, not just biological ones), showing that there were certain logical principles they had to follow. See pages 26-46 of Artificial Life by Levy (PSY KH:L 057). This includes a description of his self-reproducing automaton, and an account of how these ideas influenced space exploration.

The idea crops up frequently in science fiction, often in the extreme form of ``copying'' brain software into a computer. See for example Dust by Greg Egan, from Best New SF 7 edited by Dozois. There's a copy of this as AI box photocopy E53. The story illustrates some of the points about functionalism and the progress of time that worry its opponents. One of these is Roger Penrose in The Emperor's New Mind (OUP 1989; PSY KH:P 038). Penrose believes that before we can understand consciousness, we need to understand quantum mechanics and time, which we certainly do not now.

Jocelyn Ireson-Paine
Wed Feb 14 23:46:11 GMT 1996