Computation, Memory, Nature, and Life (2004)

Thanks for the article. This was a really nice discussion of life as computation.

That said, I disagree with Conjecture 2 on the basis that no independent storage was ever indicated for any class 4 behavior in A New Kind of Science, and "storage" achieved through encoding of information by transformation of immutable (homeostatic, anyway) state seems downright ubiquitous in nature.

In the post, John seems to draw a false dichotomy between computation and storage. I thought Stephen's book actually did a fine job of demonstrating (repeatedly, and at length) how the data and the computational machinery can be one in the same when the rules for transformation are inherent to the system. Ultimately, whether or not one thinks this true is probably decided by one's beliefs about the most basic laws of physics, and I'm rooting for a discrete universe.