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01. - Roger Penrose
Turing Home Page maintained by Andrew Hodges
14. - Turing Home Page maintained by Andrew Hodges
Introduction to this Issue: A Debate about AI
This issue refers to the discussion of Roger Penrose's ideas as stated in his Shadows of the Mind, 1994, Oxford University Press. In this book Penrose gives a more refined account of his position being due to reactions to his former book The Emperor's New Mind - Concerning Computers, Minds, and the Laws of Physics, 1989, Oxford University Press. The Platonian metaphor of shadows which some cave inhabitants perceive instead of real things alludes to the situation of a theoretician who instead of studying the mind in itself has to deal with its shadows alone. The shadow cast by the mind, as a reader may guess (following the author's suggestions in Prologue), is its ability to reason in a non-algorithmic way. This is, according to Penrose, what essentially distinguishes human minds from digital machines.
However, many intelligent people are convinced that, in principle, there is no difference between their intelligence and that of any device constructed according to the scheme of Turing machine, say, a digital computer. Some of them reacted with critical reviews of Shadows . There are also people more friendly to Penrose's vision, and some of them also wrote reviews. Such pro and contra were collected by the Editors of Psyche,, a journal of research on consciousness, and published in several issues 1n 1995. Penrose's extensive reply appeared in January 1996.
The reference to that debate, made in the form of hypertext links and, in some cases, critical comments appears here after five years, what by no means is a prompt reaction. However, it seems that in the meantime no new facts or arguments appeared which would change the picture as it emerged in 1996. The matter is so involved, the arguments offered by both sides of the debate are so subtle and refined, that a time is needed to digest all that. Comments made by the present editor, and other ones which he hopes to obtain for this site, should contribute to the task of building a conceptual order before new facts are discovered which would consideravly forward our understanding.
The references to Psyche debate are here completed with some texts by Andrew Hodges who is both Penrose's collaborator and the most competent expert in Turing's life and ideas. He has written some books on Turing, maintains the Web page devoted to Turing (from which the present photo is transferred; see above, item 14), and in other important ways contributes to our understanding the enigma called Turing. Thus, there is no one so much authorised to reflect on relations between Turing's and Penrose's approaches to this perplexing issue: Computability and Mind. Hodges' account is thoroughly based on biographical datails which throw more light on Turings achievements and dilemmas. Though many things remain not unveiled, a non-trivial conlusion follows from Hodges' study. To wit, we start to realize that Turing's attitude to the problem in question was not so stable and fixed as it is presented in the current literature. Hodges shows that not only Turing's famous achievemets but also his failures and doubts contribute to the main issue of the debate. This just one of those reasons for which Hodges's essay is worth a click to enter into its inside.
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