There's also an issue that's relevant to all of this- whether or not an automata is Turing complete is not the same as the question as to whether or not it can support "life." There are decent arguments for this claim, but it is far from obvious.
If you are Turing complete you can simulate anything - including arbitrary living systems.
...and if you aren't Turing complete, the dynamics are usually pretty limited. Surely these two things are really the same thing.
If you are Turing complete you can simulate anything - including arbitrary living systems.
...and if you aren't Turing complete, the dynamics are usually pretty limited. Surely these two things are really the same thing.
No. They aren't. First at the most basic level you have that many would argue that simulating isn't the same thing as actually being (many on LW would consider this to be wrong or so incoherent to not even be wrong and I'm inclined to sympathize with that view but it is something that needs to be considered). More seriously, just because ...
I believe that life on Earth arose spontaneously. I also believe the galaxy around me is largely devoid of life. I reconcile these things using the anthropic principle.
I also believe that fundamental cosmological constants have values convenient for the development of life. I don't know if it makes sense to pretend that those constants could have had other values - it seems to me like arguing that e could have been 2.716. But it's certainly done. And again, the anthropic principle is sometimes invoked, as an alternative to, say, God.
Suppose somebody came up with a new theory of cosmological constants, that claimed that only certain values are allowable, and that a large percentage of the allowable sets would make life possible. Then you wouldn't have to use the anthropic principle. Wouldn't you be more comfortable with that?
But if that's so, doesn't it mean that you really attach a low prior to the anthropic principle? And that you don't truly accept the anthropic principle?
How do you do Bayesian belief revision when one of your alternative hypotheses uses the anthropic principle? Can you give a strong preference to the hypothesis that does not require it? Because I know that I would.