[PaulDavisThe1st]

i think in the end it's going to come down to what you really consider "life" to be.

there is an implicit part of our definition that includes timescales and size, and this puts some limits on the type of chemistry that can be involved in order to qualify.

if you open up the definition to be things that work on totally different timescales and sizes than we consider, then i think its fair to say that the chemistry doesn't need to be similar at all.

but for things that form blobs of life on the rough range of scales found on earth, and that "do stuff" in the range of timescales that we see on earth, there are not too many choices. silicon often gets touted as an alternative because of its ability to form branched structures. do you know of any other ideas?

[clairity]

sure, chemistry has a somewhat limited palette to work with, but life happens in the gap between potential and kinetic, between hot and cold, between proton and electron. that's a tiny space but a huge gap.

dna is mostly a 4-note tune, and computers, the potential precursor to artificial life, 2. i'm sure something as vast as the universe can come up with a little more variation than skin type in those tiny little gaps.

[PaulDavisThe1st]

I don't believe that we'd recognize computer-ish artificial life as life in the sense that we're discussing here.

ps. I have my Artificial Life III conference t-shirt from 1994 :)