The Imitation Game

I propose to consider the question, ‘Can machines think?’ This should begin with definitions of the meaning of the terms ‘machine’ and ‘think.’ The definitions might be framed so as to reflect so far as possible the normal use of the words, but this attitude is dangerous.

If the meaning of the words ‘machine’ and ‘think’ are to be found by examining how they are commonly used it is difficult to escape the conclusion that the meaning and the answer to the question, ‘Can machines think?’ is to be sought in a statistical survey. But this is absurd.

Instead of attempting such a definition I shall replace the question by another, which is closely related to it and is expressed in relatively unambiguous words.

The Universal Machine

The idea behind digital computers may be explained by saying that these machines are intended to carry out any operations which could be done by a human computer. The human computer is supposed to be following fixed rules; he has no authority to deviate from them in any detail.

We may suppose that the calculator is supplied with a book of rules which he obeys. He also has an unlimited supply of paper on which he does his calculations. A characteristic of these machines is that they can be made to mimic the action of a human computer very closely.

♚ “A computer would deserve to be called intelligent if it could deceive a human into believing that it was human.”

Objections Considered

• ♔ The Theological Objection — Thinking is a function of man’s immortal soul. God has given an immortal soul to every man and woman, but not to any other animal or to machines.
• ♕ The ‘Heads in the Sand’ Objection — The consequences of machines thinking would be too dreadful. Let us hope and believe that they cannot do so.
• ♖ The Mathematical Objection — There are certain things that a machine cannot do. If it is rigged up to give answers to questions, there will be some to which it will either give a wrong answer, or fail to give an answer.
• ♗ Lady Lovelace’s Objection — The Analytical Engine has no pretensions whatever to originate anything. It can do whatever we know how to order it to perform.
• ♘ The Argument from Consciousness — Not until a machine can write a sonnet or compose a concerto because of thoughts and emotions felt, could we agree that machine equals brain.

I do not wish to give the impression that I think there is no mystery about consciousness. There is, for instance, something of a paradox connected with any attempt to localise it.