On 09 Jan 2012, at 14:50, Craig Weinberg wrote:

On Jan 9, 6:06 am, Bruno Marchal <marc...@ulb.ac.be> wrote:I agree with your general reply to Craig, but I disagree that computations are physical. That's the revisionist conception of computation, defended by Deustch, Landauer, etc. Computations have been discovered by mathematicians when trying to expalin some foundational difficulties in pure mathematics.Mathematicians aren't physical? Computations are discovered through a living nervous system, one that has been highly developed and conditioned specifically for that purpose.

`Computation and mechanism have been discovered by many people since`

`humans are there. It is related to the understanding of the difference`

`between "finite" and "infinite". The modern notion has been discovered`

`independently by many mathematicians, notably Emil Post, Alan Turing,`

`Alonzo Church, Andrzei Markov, etc.`

`With the comp. hyp., this is easily explainable, given that we are`

`somehow "made of" (in some not completely Aristotelian sense to be`

`sure) computations.`

We can implement computation in the physical worlds, but that means only that the physical reality is (at least) Turing universal. Theoretical computerscience is a branch of pure mathematics, even completely embeddableinarithmetical truth.And pure mathematics is a branch of anthropology.

`I thought you already agreed that the arithmetical truth are`

`independent of the existence of humans, from old posts you write.`

`Explain me, please, how the truth or falsity of the Riemann`

`hypothesis, or of Goldbach conjecture depend(s) on anthropology.`

`Please, explain me how the convergence or divergence of phi_(j)`

`depends on the existence of humans (with phi_i = the ith computable`

`function in an enumeration based on some universal system).`

Bruno http://iridia.ulb.ac.be/~marchal/ -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-list@googlegroups.com. To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.