A. J. Ayer

Freedom and Necessity

When I am said to have done something of my own free will it is implied that I could have acted otherwise; and it is only when it is believed that I could have acted otherwise that I am held to be morally responsible for what I have done. For a man is not thought to be morally responsible for an action that it was not in his power to avoid. But if human behaviour is entirely governed by causal laws, it is not clear how any action that is done could ever have been avoided. It may be said of the agent that he would have acted otherwise if the causes of his action had been different, but they being what they were, it seems to follow that he was bound to act as he did. Now it is commonly assumed both that men are capable of acting freely, in the sense that is required to make them morally responsible, and that human behaviour is entirely governed by causal laws: and it is the apparent conflict between these two assumptions that gives rise to the philosophical problem of the freedom of the will.

The Concept of a Person

The problems which I intend to discuss are excessively familiar to students of philosophy. They are concerned with persons in the broad sense in which every individual human being can be counted as a person. It is characteristic of persons in this sense that besides having various physical properties, including that of occupying a continuous series of spatial positions throughout a given period of time, they are also credited with various forms of consciousness. I shall not here try to offer any definition of consciousness. All I can say is that I am speaking of it in the ordinary sense in which, to be thinking about a problem, or remembering some event, or seeing or hearing something, or deciding to do something, or feeling some emotion, such as jealousy or fear, entails being conscious. I am not at this stage committing myself to any view about the way in which this notion of consciousness should be analysed.

What is a law of nature

There is a sense in which we know well enough what is ordinarily meant by a law of nature. We can give examples. Thus it is, or is believed to be, a law of nature that the orbit of a planet around the sun is an ellipse, or that arsenic is poisonous, or that the intensity of a sensation is proportionate to the logarithm of the stimulus, or that there are 303,000,000,000,000,000,000,000 molecules in one gram of hydrogen. It is not a law of nature, though it is necessarily true, that the sum of the angles of a Euclidean triangle is 180 degrees, or that all the presidents of the third French Republic were male, though this is a legal fact in its way, or that all the cigarettes which I now have in my cigarette case are made of Virginian tobacco, though this again is true and, given my tastes, not wholly accidental. But while there are many such cases in which we find no difficulty in telling whether some proposition, which we take to be true, is or is not a law of nature, there are cases where we may be in doubt. For instance, I suppose that most people take the laws of nature to include the first law of thermodynamics, the proposition that in any closed physical system the sum of energy is constant: but there are those who maintain that this principle is a convention, that it is interpreted in such a way that there is no logical possibility of its being falsified, and for this reason they may deny that it is a law of nature at all.

Can There be a Private Language

In a quite ordinary sense, it is obvious that there can be private languages. There can be, because there are. A language may be said to be private when it is devised to enable a limited number of persons to communicate with one another in a way that is not intelligible to anyone outside the group. By this criterion, thieves’ slang and family jargons are private languages. Such languages are not strictly private, in the sense that only one person uses and understands them, but there may very well be languages that are. Men have been known to keep diaries in codes-which no one else is meant to understand. A private code is not, indeed, a private language, but rather a private method of transcribing some given language. It is, however, possible that a very secretive diarist may not be satisfied with putting familiar words into an unfamiliar notation, but may prefer to invent new words : the two processes are in any case not sharply distinct. If he carries his invention far enough he can properly be said to be employing a private language. For all I know, this has actually been done.

The Principle of Utility

‘The law-giver should be no more impassioned than the geometrician. They are both solving problems by sober calculation.’ The quotation is from Jeremy Bentham’s Deontology,1 and it gives a measure both of his peculiarity and his importance as a moral philosopher. His peculiarity was that he believed that morals and politics could be made into a branch of science: his importance lies in the way in which he worked this theory out.

Identity and Reference

“Things are identical if and only if they have the same properties.” This definition of identity stems from Leibniz and is nowadays commonly known as Leibniz’s law. Does it state both a necessary and a sufficient condition of identity? It is at least doubtful whether it states a sufficient condition, since it is not obvious that things are logically incapable of being numerically different without differing in any other respect. The question turns in part on what is allowed to count as a property. Clearly if properties like “being identical with me” are admissible, it will follow trivially that no two different things can have all the same properties. No one who is not identical with me can be identical with me. On the other hand, if we consider only general properties, as we must do if the question is to be of any interest, then, as I have argued elsewhere,1 there are grounds for thinking that the principle of the identity of indiscernibles is not a necessary truth. For instance, it would not be a necessary truth, if we allowed the possibility that things which are not descriptively distinguishable may yet be distinguished demonstratively.

Two Notes on Probability

There is a fairly widespread view that, at least in one important sense of the term, probability is most properly attributed to statements: and that what is being asserted when it is said that a statement is probable, in this sense, is that it bears a certain relation to another statement, or set of statements, which may also be described as confirming, or supporting, or providing evidence for it. There are some, indeed, who maintain that this is the only sense in which it is correct to speak of probability; that what we ‘really mean’ when we assert anything to be probable is always that some statement bears the requisite relation to such and such a piece of evidence. Thus Keynes 1 assumes that every significant probability statement can be fitted into his formula ‘a/h=p’, where a is the proposition which is said to be probable, h is the evidence on which it is probable, and p is the degree of probability that h confers on a, a quantity which may or may not be numerically measurable. And Kneale 2 takes it for granted that probability is relative to evidence: if this is often overlooked, it is because in talking about probability we seldom bother to specify the evidence on which we are relying: ‘our probability statements are commonly elliptical’.3

The Identity of Indiscernibles

The principle of the identity of indiscernibles would seem, in the forms in which it is usually stated, to be at best contingently true. It does not appear that even Leibniz held it to be logically inconceivable that different things should have all their properties in common. That ‘no substances are completely similar, or differ solo numero’1 was established, in his view, by the principle of sufficient reason, but he conceded that ‘the supposition of two indiscernibles seems to be possible in abstract terms’.2 Indeed, it may plausibly be argued that even to ask whether things can be different without being discernible from one another is to admit that it is logically possible. For what sense could there be either in affirming or in denying that two things could have all their properties in common unless they were already distinguished? As Russell put it, ‘it is a sheer logical error to suppose that, if there were an ultimate distinction between subjects and predicates, subjects could be distinguished by differences of predicates.

Statements about the Past

It is characteristic of philosophers that they exercise their scepticism not so much upon particular statements or beliefs, as upon whole classes of them. They are, indeed, inclined to dispute the particular statements that are made by other philosophers; but apart from these special cases they are interested in particular statements only as examples. The weaknesses which they detect in them are those that they are supposed to share with all the members of the class of which they are taken as typical representatives. And it is this lack of discrimination that gives to philosophic doubt both its frivolity and its strength. A scientist may come to doubt some general hypothesis because the evidence for it does not meet his requirements, but his standards are not so rigorous that no hypothesis can satisfy them. It is left to the philosopher to put in question the validity of any generalization whatsoever, to cast doubt upon a general statement not because of any special weakness of its own but simply because it is a generalization. In their relations with one another men often display a lack of understanding; one does not always know what another person is thinking or feeling.

On the Analysis of Moral Judgements

‘Most of us would agree’, said F. P. Ramsey, addressing a society in Cambridge in 1925, ‘that the objectivity of good was a thing we had settled and dismissed with the existence of God. Theology and Absolute Ethics are two famous subjects which we have realized to have no real objects.’ There are many, however, who still think that these questions have not been settled; and in the meantime philosophers of Ramsey’s persuasion have grown more circumspect. Theological and ethical statements are no longer stigmatized as false or meaningless. They are merely said to be different from scientific statements. They are differently related to their evidence; or rather, a different meaning is attached to ‘evidence’ in their case. ‘Every kind of statement’, we are told, ‘has its own kind of logic.’