Graeme
Two.. being complex is not proof its impossible. Its evidence it may have taken a long long time.

Yeah, maybe. It seems a bit unlikely because we don't see nature creating vastly simply items like screwdrivers and microwaves. But that's not a proof, as you say, just a strong indicator.

Also DNA is not random, its a mechanism that life strove for (in that it needed something to work the way DNA works to improve its efficieny). And as such ANY mechanism would have done and DNA was the first workable one to come along. If life were to restart then its almost definite that Life maybe Amino Acid based but it would be different Amino Acids (prob) and there wouldnt be DNA.. it would be something else.

paulh

Once you've got a mechanism capable of self-improvement you're in the clear. It's getting that far that's the problem.