Dear Bruno, On Tuesday, January 21, 2014 8:51:14 AM UTC-5, Bruno Marchal wrote: > > > 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 theorem that takes certain axioms as true... We can build theories with other axioms... I wish to escape the prison of the Tennenbaum Theorem! > > > > > > 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
