X-Message-Number: 9288 Subject: And you thought this wasn't a humor list.... Date: Sun, 15 Mar 1998 22:25:44 -0500 From: "Perry E. Metzger" <> > From: Ettinger <> > Subject: Church-Turing etc [...] > Donaldson's recent #9272 includes a reminder that Turing machines > are SEQUENTIAL, hence not well suited for recursive functions, for > which parallel processors are much better Not only do you misrepresent Mr. Donaldson's position (which I disagree with but which is at least not ridiculous), but you display a certain, shall we say, utter ignorance of the topic you are discussing. For the record: 0) The term "recursive function" is rather meaningless in this context. You probably would mean "recursive algorithm" if you knew anything about computers. 1) Thomas Donaldson noted that recursive algorithms *don't* look much like the real world's processes and contended (inaccurately) that Turing Machines mostly execute those. (In fact, although recursive algorithms can always be translated into iterative ones and vice versa, Turing Machines tend to use iterative algorithms, to the extent that anyone ever writes programs for actual Turing Machines. (In general, no one actually writes programs for real Turing Machines -- they are useful mostly as a mathematical construct.)) 2) Sequential machines and parallel machines both execute recursive algorithms with equal ease. Maybe you'd better learn what a recursive algorithm is *first*. 3) There is also a concept being bandied about here, the "Recursively Enumerable Languages". I suggest reading a book on automata theory before attempting to post any messages using that term, unless, of course, you want to provide your readers with more amusement. > This helps to focus attention on the MEANING of the Church-Turing > thesis. IN WHAT SENSE can a Turing machine emulate any computer? > Only in the sense that it can, in principle, eventually arrive at > the same results, or print out the same answers. Boy, Mr. Ettinger, you've really managed a coup of logic there. Perhaps tomorrow you'd like to paraphrase mathematical principle for us. > Does a moving tape have feeling? Does a neuron have feelings? Perry Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9288