On 20 Jan 2014, at 21:17, Alberto G. Corona wrote:
Computation is understood as whatever made by a digital computer or something that can be emulated (or aproximated) by a digital computer.
OK. That's a good definition, and it is correct if ... we assume Church's thesis.
So everything is a computation.
Goddam! Why. Even just about what is true in arithmetic cannot be emulated by any computer.
I am afraid you might not really grasp what a computer is, conceptually. See my answer to stephen yesterday, which shows wahy Church thesis entails that most attribute of *machines* cannot be computed by a machine.
Or think about Cantor theorem. The set of functions from N top N is not enumerable, yet the set of *computable* functions is enumerable.
That is a useless definition. because it embrace everything.
For a mathematician, the computable is only a very tiny part of the truth.
Everything is legoland because everything can be emulated using lego pieces? No, my dear legologist.
Not veything can be emulated by a computer. few things actually in usual math. Some constructivist reduces math so that everything becomes computable, but even there, few agree. In Brouwer intuitionist analysis he uses the axiom "all function are continuous" or "all functions are computable", but this is very special approach, and not well suited to study computationalism (which becomes trivial somehow there).
What about this definition? Computation is whatever that reduces entropy.
It will not work, because all computation can be done in a way which does not change the entropy at all. See Landauer, Zurek, etc.
Only erasing information change entropy, and you don't need to erase information to compute.
In information terms, in the human context, computation is whatever that reduces uncertainty producing useful information and thus, in the environment of human society, a computer program is used ultimately to get that information and reduce entropy, that is to increase order in society, or at least for the human that uses it.
The UD generates uncertainty (from inside).
A simulation is an special case of the latter. So there are things that are computations: what the living beings do at the chemical, physiological or nervous levels (and rational, social and technological level in case of humans) . But there are things that are not computations: almost everything else.
That is the case with the definition you started above, and which is the one used by theoretical computer scientist.
Bruno http://iridia.ulb.ac.be/~marchal/ -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
