Monique asked:

Can you explain to me how a machine can think?

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Machines such as computers can calculate, but calculating is not the same as thinking. A chess
computer running a program like Deeper Blue, the program that defeated Kasparov, calculates
moves at an amazing speed but it does not think. It does not have beliefs or desires. It is not
conscious.

The mathematician Alan Turing once proposed a test which could be used to settle the question
whether a computer met the criteria for being an 'artificial intelligence', that is to say, a test which
would determine whether the computer was not only able to calculate but also to think, as we do.

The idea of the test is childishly simple. Suppose you log onto a chat line. You have a conversation
with an individual who calls themself 'Daniel'. How do you know that Daniel is not a machine
programmed with set responses to the words that you type on the screen? If Daniel is able to
continue to hold up an intelligent conversation, respond appropriately to whatever questions you
asked, then you would conclude that Daniel was capable of thinking. What Turing said was that it is
irrelevant whether Daniel is a human being or a machine. A machine that can do what Daniel does is
intelligent, is capable of thinking, by definition.

Your question, however, is how it is possible that a machine like 'Daniel', a machine with genuine
'artificial intelligence', could ever exist.

Is that a technical question or a philosophical question?

Daniel's 'brain' is not made of biological tissue but metal, silicon and plastic. But why should biological
tissue be the only material that is capable of producing thoughts? On the other hand, perhaps you are
just as puzzled (as I am) by the question how a person can think!

Daniel does not have a body, as we have. He sits motionless on a desk. His only action is to spew
out words when words are fed in. For me, that is a serious, perhaps fatal objection, which is why I am
not finally convinced by the 'Turing test'. I share the view held by a number of researchers in this area
that a genuine 'artificial intelligence' would have to possess something analogous to arms and legs,
eyes and ears. I would have to be an agent, and not merely a language user.

Geoffrey Klempner