Alan Turing on whether computers can have a sense of humour

In his 1950 article ‘Computing Machinery and Intelligence’, published in Mind, Alan Turing speculates on the future of computer intelligence and suggests boldly: “at the end of the century the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted.”

Turing addresses various arguments against the possibility of computers “thinking”, one species of which he calls ‘Arguments from Various Disabilities’.

These arguments take the form, “I grant you that you can make machines do all the things you have mentioned but you will never be able to make one to do X.” Numerous features X are suggested in this connexion I offer a selection:

Be kind, resourceful, beautiful, friendly, have initiative, have a sense of humour, tell right from wrong, make mistakes, fall in love, enjoy strawberries and cream, make some one fall in love with it, learn from experience, use words properly, be the subject of its own thought, have as much diversity of behaviour as a man, do something really new.

Turing suggests that “the criticism that a machine cannot have much diversity of behaviour” is due to a failure to imagine the necessary increase in computing power for such “diversity of behaviour” to occur. Such arguments, he suggests:

“… are mostly founded on the principle of scientific induction. A man has seen thousands of machines in his lifetime. From what he sees of them he draws a number of general conclusions. They are ugly, each is designed for a very limited purpose, when required for a minutely different purpose they are useless, the variety of behaviour of any one of them is very small, etc., etc. Naturally he concludes that these are necessary properties of machines in general. Many of these limitations are associated with the very small storage capacity of most machines.”

Turing focuses on one particular ‘feature’ which he lists alongside “have a sense of humour” and “use words properly” in the roll call of peculiarly human traits which some say machines will never have:

The claim that “machines cannot make mistakes” seems a curious one. One is tempted to retort, “Are they any the worse for that?” But let us adopt a more sympathetic attitude, and try to see what is really meant. I think this criticism can be explained in terms of the imitation game. It is claimed that the interrogator could distinguish the machine from the man simply by setting them a number of problems in arithmetic. The machine would be unmasked because of its deadly accuracy. The reply to this is simple. The machine (programmed for playing the game) would not attempt to give the right answers to the arithmetic problems. It would deliberately introduce mistakes in a manner calculated to confuse the interrogator.

This train of thought can be applied to the idea of machines having a sense of humour: the ‘deliberate introduction of mistakes’ is one way of describing ‘making a joke’. A joke is almost always something other than a “deadly accurate” statement. An amusingly cutting remark, or a bit of satire might be described as ‘deadly accurate’, but more often than not jokes are whimsical digressions from fact and reality. The ‘proper use of words’ in the context of making a joke involves such as things as exaggeration, the misattribution of characteristics, and being intentionally misguiding: in other words, making deliberate mistakes.

Turing equates the idea that machines cannot do such things as “have a sense of humour” or “make mistakes” with a failure to imagine the computing power necessary for such behaviour to occur:

The criticism that a machine cannot have much diversity of behaviour is just a way of saying that it cannot have much storage capacity. Until fairly recently a storage capacity of even a thousand digits was very rare.

Unhampered by “scientific induction”, Turing himself is happy to make this leap of imagination:

The popular view that scientists proceed inexorably from well-established fact to well-established fact, never being influenced by any improved conjecture, is quite mistaken. Provided it is made clear which are proved facts and which are conjectures, no harm can result. Conjectures are of great importance since they suggest useful lines of research.

Turing was conjecturing in 1950. Seven decades later computers may not “have a sense of humour” but they are starting to make jokes. A bit more computing power and they might even start finding them funny.

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