On Tue, Jan 21, 2014 at 2:51 PM, Bruno Marchal <[email protected]> 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 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. > Like the guys from Erlangen and Lorenzen. I gave myself some time with this, until I decided it was just prohibition/denial: "We just all pretend that weird stuff does not exist. Only not-weird stuff is real because we have clarity", is what I remember... I am still amazed by how popular and how much support this seemed to get. Difficult to stay open and build understanding of these approaches for me. PGC > 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. > -- 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.
