The problem of Other Minds is a true philosophical enigma. It is apt to strike children with no philosophical education whatsoever, yet remains intractable to many academics. Broadly speaking, the problem can be divided into three questions. Firstly, how do I come to believe that there are minds in the world other than my own? Secondly, how can I justify my belief that there are minds in the world other than my own? Thirdly, what can I state about the mental states of minds other than my own?. The question we are dealing with here falls largely into the third category, although of course issues relating to the other two will also be involved. Firstly, it is imperative to assert that, in looking for 'knowledge', we are not aiming for logical certainties - we are not aiming to show that any propositions about other minds can be demonstrated with absolute certainty equivalent to that of mathematical truths. Philosophy ever since Descartes has tended to be defined by scepticism: either it aims to produce sceptical theories or it aims to refute them. And sceptics tend towards extremity in their doubts. It must be stated here and now that there are not, and never can be, any theories that prove demonstratively that other minds exist, or that I know others' mental states. This is not what should be aimed at in attempting to solve the problem. As Austin puts it "To suppose that the question 'How do I know that Tom is angry?' is meant to mean 'How do I introspect Tom's feelings?' is simply barking up the wrong gum-tree." Most philosophers agree that their theories only bestow a greater or lesser amount of probability onto statements about other minds (although there are exceptions, e.g. Peter Strawson's attempt to argue transcendentally for the existence of other minds through our own self-consciousness). There have been a number of different attempts to do this. J.S. Mill, who produced the first known formulation of the Other Minds problem, used the so-called 'Argument from Analogy' both to explain how we come to believe in other minds and to justify this belief. Briefly, the argument holds that I am directly aware of mental states in myself, and I am aware of the behaviour of mine that results from and is caused by these mental states. As I can observe similar physical behaviour in others, I draw the analogy that it is caused by the same (or at least similar) mental states to my own. As in all arguments from analogy, I assume that because x is similar to y in some respects, it will be similar in others. So as I know how I behave if I am feeling, say, angry, I assume in someone else's case that his behaviour is an indication of the mental state I call 'anger'. My opinion in this respect is aided by the fact that most humans' behaviour when they claim to be angry is broadly similar. The argument from analogy, also employed by Bertrand Russell in a slightly simplified form, is subject to a devastating criticism. Unlike most analogies, in the case of other minds, there is no conceivable way of verifying the conclusion we make. We have no way of discovering whether someone else is angry or not, and our position means that this is a necessary disadvantage. The only way to have someone else's experiences would to become that person, and in doing that, I would no longer be myself and I would no longer be having someone else's experiences. Thus it is impossible to conceive of any set of experimental circumstances under which I would be able to ascertain whether or not the human who is expressing anger-behaviour really is angry or not. And as Norman Malcolm has pointed out, as there are no conceivable criteria I could use to determine whether someone is angry or not, simply claiming that they are angry is a meaningless statement. Many philosophers, perceiving this fatal flaw in the argument from analogy, have attempted to produce theories on other minds that are not based on analogy. Malcolm himself held that the problem lies in the belief that in looking for evidence of other minds, we need to start off from our own case and then look for evidence that other cases resemble my own in other humans. He claimed, characteristically following Wittgenstein, that statements about mental states in others have no 'special' status but rather that they are 'primitive, natural expressions' of the state in question. In other words, 'my leg hurts' is equivalent to non-verbal behavioural expressions of having a painful leg such as crying, limping, or holding my leg. The statements are not propositions as such, and so have no 'truth-value'. In my view, there are huge problems with this account. Firstly, its explanatory power is exceedingly limited as it makes no distinction between those who are pretending to be in a mental state and those who genuinely have it. How does it help us to believe that our world is not populated by robots? Secondly, it does not sufficiently explain how we came to attach the words we do to our mental states. Crying and limping are 'natural', animistic reactions to pain, but language is learned from others. How can this be accounted for? Other philosophers have been less successful in escaping the clutches of the argument from analogy. H.H. Price, in his article Our Evidence for the Existence of Other Minds, seems to dismiss it, but then employs it himself, simply changing the terms of the analogy, claiming that we come to believe in other minds through other humans' use of informative language, not through their behaviour. A.J. Ayer, in his essay One's Knowledge of Other Minds, argues that the belief in other minds is at least as justifiable as any other inductive argument. When we refer to the mental states of others, the descriptive content of that reference need not necessarily include any reference to the possessor of that mental state. There is no contradiction in asserting that I could have had that mental state. Implicit in this argument is Ayer's belief that a person is no more than the aggregate of all his properties. Thus, as none of those properties are necessarily unavailable to me, I make no contradiction when I say that I could have had them: "But even if my friend has no properties which make him an exception to the rule about feeling pain, may he not still be an exception just as being the person that he is? And in that case how can the rest of us know whether or not he really does feel pain? But the answer to this is that nothing is described by his being the person that he is except the possession of certain properties. If, per impossible, we could test for all the properties that he possesses, and found that they did not produce a counter-example to our general hypothesis about the conditions in which pain is felt, our knowledge would be in this respect as good as his: there would be nothing further left for us to discover." (pp 213-4). And thus, if I could have had the mental states in question, I could be the person who had them. And if I could be that person, I could verify whether that mental state actually exists or not. Ayer's reasoning seems valid enough, but it is hard to know precisely what he means. It seems certain that in referring to mental states, it is implicit that someone owns (or is) the mind in which those states are occurring. Although Ayer is right in his claim that we need not refer to the 'owner' of the state when we talk about the state itself, and therefore that the owner 'could' be us, this doesn't seem to address the issue at hand. The problem is one of other minds, and we are, all of us, in a situation where we find ourselves confronted with apparent minds other than our own which are problematic. >From the realisation that a belief in other minds can only arise through observation of the behaviour of others arose the 'cul-de-sac' philosophy of logical behaviourism. This theory, now largely discredited, holds that all statements about mental states can be translated, without loss of meaning, into statements about observable behaviour. Thus to say that Jones is in pain is to say that (for instance) Jones is wincing, crying out, grimacing etc. The statements are equivalent, and consequently the problem of other minds is not so much solved by behaviourists as dissolved. But the terminal problem for behaviourists lies in the case of first-person psychological statements. We certainly don't learn about our own mental states by observing our own behaviour. When I say 'I have a headache', I don't mean that I am clutching my head, that I am taking aspirin etc. The feeling of the headache seems in some way to pre-empt all of this behaviour, and generally to be the primary cause of it. The behaviourists made a valiant attempt to solve the problem of other minds by doing away with the asymmetry between my mental states (normally taken to be learnt through introspection), and the mental states of others (normally taken to be learnt through introspection), but they ultimately failed because their account of first-person psychological statements was utterly inadequate. Wittgenstein, in his 1953 work Philosophical Investigations, attempted to show that the construction of a private language (a language that no-one other than the creator is logically capable of understanding) was impossible because languages must follow rules, and it would be impossible for a language with no external reference to follow rules. For instance, if I have a certain experience x one day and call it 'pain', and then have another experience y the next day which happens to be different to the one I had the day before but which seems to me identical, and so I also call it 'pain', how, as far a I am concerned would this situation differ from one in which the second experience was actually x? It would not, so I could conceivably be wrong in every statement I make regarding my own mental states. The point Wittgenstein is trying to bring out is that, contrary to the philosophies of Cartesianism and traditional empiricism, the language we couch our mental statements in is a public language: the words we use only acquire their meaning through public usage. And thus if there were no other minds in the world other than our own, we could not make publicly understandable statements about our mental states. This is a powerful argument, although it is open to at least two criticisms. Firstly, it is claimed by some philosophers that it leads inexorably to a form of behaviourism in which my knowledge of my own mental states through introspection is not accounted for. Secondly, the argument tells us very little about the content of other minds. What is the relation between words and mental states?, and more importantly, how could it conceivably be discovered? By appeal to our own case? That would just beg the question. Nevertheless, I believe that Wittgenstein's approach is the correct one. It is a truism to say that I cannot have your experiences, and it always remains logically possible that an malin génie has set me amongst a world of unthinking, unfeeling robots who have been programmed to exhibit behaviour (both verbal and non-verbal) leading me to assume that they have thoughts and feelings. But this seems somewhat unlikely. Rather, it seems more sensible to believe that there are minds animating all the beings around me. If I am not to be subject to the sorts of criticisms that Malcolm makes of the argument from analogy, then I must define some sort of criteria for asserting that Mr X is feeling y etc. And my only criteria, of course, can be my observations of his behaviour. To ensure that my interpretations are as accurate as can be, I must take into account everything about him: his simple overt behaviour, his environment and social context, his biological make-up etc. And my reference point can only be myself, as I am the only example in the world of whose mental states I can be confident. So as far as X's circumstances and behaviour mirror my own, I can say that his mental states mirror mine. And I can go slightly further: I can claim that my knowledge of my own case can give me an idea of how certain properties and the connections between them can affect mental states, and so if I notice some property x in X that happens not to belong to me but of which its significance concerning mental states I am aware, then I can make statements regarding X's mental states with a certain confidence. If this conclusion seems rather weak, then I can only appeal to the enigmatic nature of the problem itself and ask others to better it. Finally, I would like to mention an observation of mine regarding the nature of the problem itself. The problem of other minds arises because we have no certain criteria for ascertaining the possessing of a mind (or mental states) by a being, and this in turn arises because we do not know precisely what a mind is. If philosophers of mind ever produce a theory of mind which provides us with knowledge, to a certain extent, of the nature of mind, then it would at least theoretically be possible to have criteria for the possessing of mind, which would provide very good foundations for the solving of the problem of other minds. Bibliography Sartre by Arthur C. Danto. Fontana, 1975. Strawson's Transcendental Deduction of Other Minds by J.L. Martin in New Essays in the Philosophy of Mind ed. John-King Farlow and Roger A. Shiner. Canadian Association for Publishing in Philosophy, 1975. The Philosophy of Sartre by Mary Warnock. Hutchinson & co., 1965. Analogy by Bertrand Russell in Essays on Other Minds ed. Thomas O. Buford. University of Illinois Press, 1970. Our Evidence for the Existence of Other Minds by H.H. Price in Essays on Other Minds. Wittgenstein's Philosophical Investigations by Norman Malcolm in Essays on Other Minds. Knowledge of Other Minds by Norman Malcolm in Essays on Other Minds. Other Minds by J.L. Austin in Austin's Philosophical Papers ed. J.O. Urmson and G.J. Warnock. Clarendon Press, 1979. One's Knowledge of Other Minds by A.J. Ayer in Philosophical Essays by Ayer. Macmillan and co., 1953. The Mind and its Place in Nature by C.D. Broad. London, 1925. The Concept of Mind by Gilbert Ryle. London, 1949. The Oxford Companion to Philosophy ed. Ted Honderich. Oxford, 1995.