Why can Conway’s Game of Life be classified as a universal machine?
I was recently reading about artificial life and came across the statement, "Conway’s Game of Life demonstrates enough complexity to be classified as a universal machine." I only had a rough understanding of what a universal machine is, and Wikipedia only brought me as close to understanding as Wikipedia ever does. I wonder if anyone could shed some light on this very sexy statement?
Conway's Game of Life seems, to me, to be a lovely distraction with some tremendous implications: I can't make the leap between that and calculator? Is that even the leap that I should be making?
Answer
Paul Rendell implemented a Turing machine in Life. Gliders represent signals, and interactions between them are gates and logic that together can create larger components which implement the Turing machine.
Basically, any automatic machinery that can implement AND, OR, and NOT can be combined together in complex enough ways to be Turing-complete. It's not a useful way to compute, but it meets the criteria.