I.—COMPUTING MACHINERY AND INTELLIGENCE

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 and so who to the I be to the game as a for who in the two be in This is expressed in for from which I a can a or a of and and by the of we that it but that it an at be by be by be by be or it it This to be a of the of to the form of this the by which be that a is to be the and to then to the but of be in to this the to that a man is to be that It is in the of It may be the to but it of A is to but B B but A Instead of this it is to the that I that to the and of he be to the game as a The game the B is used in the of to or it in to a of such a the of which I to a as or It about but to be to a of a is a and I the I a a a so the to answer this in the I he the as but the as and as in the I he it as This I to such as the in the of a of a with to it from to I that of who the from be to it be the then be to I to the that I is about for of a with to But I to be we can answer the question with which we are in this the that can make machines the but be to make to X are in this I a a of tell from make in and make in with from use words be the of as of as a new of are as by the is for I they are the of A man of machines in his he of them he a of are is for a for a they are the of of of them is he that are of machines in of are with the of that the of is in to machines other The definition as is in the A of it possible to to a of the of of the are of a the and that he it by I should that he of his in other The and of to be to which to A of must be are to be we may that and that it is to to be about of the that The to and may the as a might be to this but to make so be is about this is that it to of the other to the of the of man and as man and or man and The that make a is to they the for But a and try to is I this can be in terms of the It is that the interrogator the from the man by them a of in The be of The to this is The for the to the to the It in a to the A an as to of a to make in the this of the is But we the to it It to me that this a two of may call them of and of of are to or which the to it to to the of such is therefore machines are definition they are of of this we can that can make of conclusion can meaning is to the from the The for or in a is we that the an of is at for that a make this of It might but a it might for by must such a to to The that a be the of can of be it can be that the with of a to at to the who with for the to a of the be to this as of the at that this of a can be It may be used to in or to the of in the of it can so as to are of the The that a of is a of that it a of a The that we are are of the from that a can of and the of that the make of an It is that the it may for it must be is the in of from a by it to It can we how to it to This is by who that it may be possible to which for or in in a which as a for this is possible in or is a and question, by of But it that the machines or at the this I in with It be that be that the machines in question the but that the to her to that they It is possible that the machines in question in a this suppose that the The a so and it by be to the in this to the or to them to that be This question be the of A of that a can This may be for a with the is new the can be that that he the of the in by or the of A of the says that a can by This is a and can be me by with This is I to to them to or I a I it in a I to suppose the to be the as it I and the is a for me for by the the is me to the of but I to the I I this to He that such are to and reflect the This to the from and far from the of It is a of we must consider but it is that the of as as of a the from a a a or The that machines to is I to a to which and are This is the that as as a is to a of that the with It is a but that it is A of so is that then that is in the of from and The is a A in the about the of a a may make a to the of the It may be this to be to the of the with a It is that a must be from a But we to the of the the interrogator be to of this The can be we consider other A is a of of the used for of of in a and so are for in the It be possible for a to the to a but it be of the of answer. to the of about it be to at the with the of it be difficult for the interrogator to the from the It is possible to a of to a man should in of might for a that is to a and to a but by may that it is to But may from this to of to from to be this I this it is that we be I shall try to the but I I shall it It to man a of of by which be his he be a But are such so be The is I the is put I this is the used may be a of and of to the of I such as which can and of which can be of I of as to a such as he If we of which his for of by which he his in the the is we that it is that by of of a but that such a by such we so of the of of as of of The we of for such is and we of which we are such can that such be suppose we be of such they a it should be possible to by about it to and this a a But this to be the I the a of the with with two I to from about the to be to to I that the is with the of and the meaning of the of and to we should to the statistical at for is It is difficult to so as to new them it a to in and The that to the of with but be of the to This is to a can in that to in in of with that in can about This is and that is the of may be A might as the as a man who is as a and a The interrogator can such questions as the in The man by or the answer of The can at and so the interrogator the is an which the a it be to use this to answer to But then the be to the of the this might cause the to be a so that the interrogator might be to make the identification. the other he might be to by may If is it be to The be as to that which the interrogator to and of the with his to the put the a The that I of a to If I I should such to the in as I I shall for a to which that the can we tell it to that a man can an the and that it to a and then a by a be an of an is to to a the from such cause a which the of the is the by such an and the is a for and is for to be for the The of them to be to in this to of to such a to in A are to such a may to a of and to be to this we ‘Can a be to be The of an is the of the or the we which we can in This we to the it is a of which we must we are to the But then in we a to be and so in this we to the or we to the which in the the is be a two to be should be described as to The that can be for the expressed at the of be that by for the end of the and then the But can we in the should be the is to be I the problem is of in to be but it that be for the of the of the from to I to the and that a is used for the of of it is used for the of I should be for of the at a of the is A of be a by It is to the of of the machines at of machines which can be as of about a the This should a of which of in problem then is to how to machines to the of I about a of a so that about the might the the the of to an we are to a about the which it to the that it is may three The of the at The to which it to be described as to which it Instead of to a to the try to which the If this then to an of the the is a as it from the and of and are from of is that is so in the that it can be The of in the we can as a to be the as for the problem two The and the two closely to a at the must with such and how it can then try and it is or is an this and by the may that this be The of the is a for The by the of should be to it is the that he is to If he can a cause for he can of the of which It be possible to the to the as to a normal It for be with so that it be to and the it might But might be by the to the other of It must be be about the The of that can that in and can by or and with the can be or this of The to be so that which the of a are to be a the of of the which to definitions the of the I with such and in it a but the for the to be The use of and can at be a of the the other of to the the of which can the of and the a to he the be by a the form of a It is therefore to other of If are it is possible to a by and to in a are to be the The use of this the of and may as to the which is in the might try to make it as as possible with the might a of the the be with definitions and The of by an the form of but may be described as The should be so that as as an is as the suppose the says to the This may cause says to be the such might that says is may to the the and by the of the that the actually but the is The of used by the be such as the might for be of But this that we are to the of the of the such as use a it is a of which by can a to the The that can be by a that are to be of a as in the such be which the in which the of the are to be at is a is a of of which is to so far as to the of the is make the a and a the a and a to of this might be is use the in or to be another, use the of may be by but may be by the by The of a may to can the of of the should how the might it might The are This is The of the is that the which in the are of a an The may a with the of the of a is that be of is he may be to to his This should to the of a from a of This is in with normal a to object is then to a of the of the at in the This object can be with a The that can we how to it to in of of the which we can put the in that we make of at or which we as in a from the in but a which to or to of for in the game by a of and is that is to be in a should this with the of that are a of they they be It is to a in a A is we are for a of for we to a and which to the of the of we might at then try and we a that we might at we a a This the that it is to of the that but the that may try the but this is are The the that may be an in the which to be Now the may be as a for a form of which the other is a of the to be the