1950/10/01 by Alan Turing, A. M. TURING · 2 voices · 167 citations
Computer Science · #Computability, Logic, AI Algorithms #Semantic Web and Ontologies
paper · doi:10.1093/mind/lix.236.433
openalex publication_date 1950/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
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 such as a Gallup poll. 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 new form of the problem can be described in terms of a game which we call the ‘imitation game’. It is played with three people, a man (A), a woman (B), and an interrogator (C) who may be of either sex. The interrogator stays in a room apart from the other two. The object of the game for the interrogator is to determine which of the other two is the man and which is the woman. He knows them by labels X and Y, and at the end of the game he says either ‘X is A and Y is B’ or ‘X is B and Y is A’. The interrogator is allowed to put questions to A and B thus: C: Will X please tell me the length of his or her hair? Now suppose X is actually A, then A must answer. It is A's object in the game to try and cause C to make the wrong identification. His answer might therefore be ‘My hair is shingled, and the longest strands are about nine inches long.’ that of may the interrogator the should be or The is to a the two the question and can be by an The object of the game for the is to the The for her is to can such as the to to her but it as the man can make the question, a the of A in this Will the interrogator as the game is played this as he the game is played a man and a questions replace ‘Can machines think?’ as is the answer to this new form of the may this new question a to This question we an The new problem the of a the and the of a or to be to a which is from the It is possible that at this might be but this we should in to make a by it in such The form in which we the problem this in the which the interrogator from or the other or other of the may be by questions and me a the of the me this I to about and then as I at and other at and at It is a of The question and answer to be for of the of that we to to the for to in to a man for in a an The of game make The can they consider it as as they please about or but the interrogator The game may be the that the are the If the man to try and to be the he make a He be at by and in machines which to be described as but which is from a man This is a but at we can that a can be to the game we be by this It might be that the ‘imitation the for the may be other of the of a This may but I it is that is of this is to the of the and it be that the is to try to that be by a The question which we put in be we we by the It is that we should to of to be used in to the an or of may a which but of be described by they a which is we to from the machines in the It is difficult to the definitions so as to three might for that the of should be of but this be for it is possible to a from a of the of a so be a of of the but we be to it as a of a This to the that of should be are the to so in of the that the in by a of an or this we to in This at to be a I shall to that it is so in this a of the and of It may be that this of machines with for be to it that are to a in the are a of in and it may be try the It be to the of the A of be and to how the The answer is that we are in the game the at but are which But this is the answer. shall this question in a The may be by that machines are to which be by a The is to be he to from them in may suppose that are in a which is he is put to a new He an of which he his He may his and a but this is If we use the as a definition we shall be in of of this by an of the by which the is A can be as of three The is a of and to the this is the which he his or that which his of is so far as the in his a of the to his The is the which the in a are from to can be such as by but in machines such as are that the of to the is in the by a of the It is then the of It is the of the to that are and in the The is so that this The in the is of for a might of are to the of the in which the of are in A might the in to that in and put the the to it in the expressed in It be in a form such as says which of possible is to be the two this the is that described the It be that the and so of The the to be in the of the in which they are but an such as the in and from be or the in of are they make it possible for a of to be and is but in so to but the and a to call at the his to to her are can can a and for in the which he he for and which to call for the and to the he he the with The must it as a that can be and to the we and that they can in the of a The of which we described as is of a they to If to make a the of the in to how it is and then the answer the form of an is described as a to the to put the the so that it the of a is a with a the of a or such might for the and put the such a is described as I use this It is possible to determine from a it a for a can be by such as the the of the for a is in the of a with an a can used at a can but we can and as and be The of a is an of at from to such a the but it the his at that such a The which be a but the of the of the The to be and The that to be to of a is to the that are and that the is and are in a we that this use of be of in is so that it is that we it in the are at as as the is The of is to be a If we to such we should for of The in the may be the are the machines which by or from to are for the of them to be are such But are of which can be of as in the for a it is a that must be or must be but for we can about an of a we might consider a which a but may be by a which can be from in a is to in of the of the This be described as The of the is described by the of the may be or is an or of The at is by the and to the The the of the are described by the This is of can be described by such they a of possible It that the of the and the it is possible to This is of that from the of the at of as described by the and of it should be possible to The which we are to that by The of the as a is such that in the can an at a The of a by a of a at might make the a man by an a or It is an of the which we that this we consider the machines of the of the at of we the of But the of of which such a is is the for the at it about about this with of the described which three It is difficult to the of should be so The a to the used by a It must be possible to the of the of which might the suppose that from to are used as in are the is allowed of with room for the of is This is about the of of three machines put The to the two of the of is the of the the a of about and the of about If two machines are put must be to the of the This to the of such as with a of with a of to about a of the to a it is possible to it is this should be by of a it be the the of The game then be played with the in question and the and the interrogator be to the must an as as it must be for new which it is to This of that they can is described by that they are The of machines with this the of it is to new machines to can be with for It be that as a of this are in a may consider the at the end of It that the question, ‘Can machines think?’ should be by which in the If we we can make this and machines which But in of the we that either of questions is to it that by this to an of and it with an C can be to the of A in the the of B by a may consider the to and we are to to the question, ‘Can machines think?’ and the of it at the end of the the form of the for as to the of the and we must at to to be in this It for the I in the the form of the I that in about it be possible to with a of about to make them the game so that an interrogator of the of The question, ‘Can machines I to be to I that at the end of the the use of words and so that be to of machines to be I that is by The that from to by is it is which are and which are can are of they of I to consider to is a of an to man and but to other or to or can I to of but to in I should the with for is a to the and the is man and the other The of the we consider how it might to a of other the that But this and to the It to me that the a of the of the It is that are that He such as to but should we that He to a an He might that He this in with a which the with an to to the of this of form may be for the of It may it is difficult to But this that we it be that He consider the for a The in question are in the of this attempting to such machines we should be His of we are in the of we in either of His for the that He this is I with they may be used to found in the the of it that the the and to about a and the of the that it should at an of the such an that it a of machines be and that they This is expressed so as in the form But it of who about it at to that is in to the of It is he can be to be for then is of his The of the is with this It is to be in people, they the of and are to in the of this I that this is to be this should be sought in the of are a of of which can be used to that are to the of The of is as and that in can be which can be the the is are in to and The is the to it to the can be used in a for is to be used we in to of in terms of and machines in terms of The in question to a of which is a with an It that are that such a If it is to to questions as in the be questions to which it either a wrong or to an answer at is allowed for a of be such and questions which be by may be by are of for the that the questions are of the to which an answer or is questions such as of The questions that we the machines must are of this the as Will this answer to The are to be by a of in a which be that used in the described a to the which is it can be that the answer is either wrong or This is the it is that it a of machines to which the is The answer to this is that it is that are to the of it of that such to the But I this can be so of machines is the question, and a we that this answer must be and this a of this It is but I should be to wrong to questions to be in at such of the of the can be such an in to the which we be question of might be but then might be other machines 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