16 A. J. Ayer (1910–1989) T. L. S. SPRIGGE Language, Truth and Logic General character of the book A. J. Ayer rose to early philosophical fame with the publication in 1936, when he was 25 years old, of what remained his most famous, or infamous, book, Language, Truth and Logic. The work is his own version of the logical positivism characteristic of the Vienna Circle (whose meetings he had attended for three months in 1932–3), his outlook being closest to that of their leader, Moritz Schlick. The book is also strongly influenced by the British empiricist tradition, in particular by Hume and Russell. It was something of a bombshell to British philosophers and became for them the paradigm statement of logical positivism, threatening the outlook of some, providing an exciting intellectual liberation for others. The book opens with the striking statement: The traditional disputes of philosophers are, for the most part, as unwarranted as they are unfruitful. The surest way to end them is to establish beyond question what should be the purpose and method of philosophical enquiry. (1946: 33) So far as philosophy goes, Ayer’s concern is to show the meaninglessness of meta- physical theories about a reality beyond the empirical. More generally, he also claims to show that religious statements, as usually now intended, are meaningless, as also are statements of fundamental ethical principle (except as mere expressions of emotion).1 To establish the meaninglessness of all such statements Ayer puts forward the veri- fication principle. According to this a statement is factually significant to any given person, if, and only if, he knows how to verify the proposition which it purports to express – that is, if he knows what observations would lead him, under certain conditions, to accept the proposition as being true, or reject it as being false. If, on the other hand, the putative proposition is of such a character that the assumption of its truth, or falsehood, is consistent with any assumption whatso- ever concerning the nature of his future experience, then, as far as he is concerned, 205 T. L. S. SPRIGGE it is, if not a tautology, a mere pseudo-proposition. The sentence expressing it may be emotionally significant to him; but it is not literally significant. (1946: 35) Thus a meaningful statement must either be empirically verifiable, or be a tautology, that is, analytic or true by definition. The passage just quoted is supposed to be a “somewhat vague” formulation of a principle that Ayer proceeds to express more precisely. But actually, since it turned out difficult to find a satisfactory precise formulation, it remains as good a formulation as any. Since there are two types of meaningful statement for Ayer, the empirically verifi- able and the analytic, his account of each of these will be considered in turn. Empirical statements Ayer distinguishes between strong and weak verification. A strongly verifiable proposi- tion is one which could be conclusively established by sense experience, a weakly verifiable proposition is one which could be made probable by sense experience. It is too much to demand strong verifiability of a meaningful factual statement (it is doubtful indeed if any proposition is strongly verifiable) and so some form of weak verifiability is the appropriate criterion. Ayer tries to give an exact formulation of this as follows. Let us call a proposition which records an actual or possible observation an experiential proposition. Then we may say that it is the mark of a genuine factual proposition, not that it should be equivalent to an experiential proposition, or any finite number of experiential propositions, but simply that some experiential proposition can be deduced from it in conjunction with certain other premises without being deducible from these other premises alone. (1946: 38–9) The general idea, here, is clear enough. A meaningful empirical statement must be a genuine aid to the anticipation of the experiences we can expect to have under various circumstances (identified in terms of the other experiences then available), though it need not tell us what experiences to expect all on its own. To illustrate his point Ayer gives an example of two questions that might be raised about a painting. (1) Was it painted by Goya? (2) Is the painting a set of ideas in God’s mind? People may disagree in their answers to each of these questions, but in the first case they know what kind of empirical evidence would support their claim against that of their opponents, in the latter they do not (1946: 40). Later in the work, especially in chapter VIII, “Solutions of Outstanding Philosophical Disputes,” Ayer shows, or claims to show, how metaphysical questions are all mean- ingless in much the same manner, unless they are understood, as is often appropriate, as misleading ways of discussing how propositions of a certain type are to be analyzed. (See the section below, “What is the task of philosophy?”) Unfortunately Ayer later discovered that the technical formulation of this revelation of the meaninglessness of metaphysical questions was unsatisfactory. This is because any statement whatever, call it “P,” can meet the condition simply in virtue of the fact that its conjunction with “If P, then O” (where “O” is a experiential statement)2 entails 206 A. J. AYER “O,” as “If P then O” does not alone. Thus “God is annoyed,” which Ayer would hate to find meaningful, entails an observation statement “You will shortly hear thunder” when conjoined with “If God is annoyed with what you said, you will shortly hear thunder.” In his 1946 introduction to the second edition Ayer offered a more complicated formula- tion, which, however, he had later to concede, fell foul of technical criticisms from Alonzo Church and C. G. Hempel. (See Church 1949 and Hempel 1959.) If one is not too infatuated with semi-formalization, however, one can, surely, say clearly enough what Ayer was getting at, whether one accepts it or not. Surely the real point of the verification principle, so far as factual (non-analytic) statements go, was this. Such a statement is meaningful to a particular individual if and only if it is possible for either it or its negation to be a practical aid to him in forming correct expectations about what he is liable to experience in the future. If there is no such possibility then it is factually meaningless, however much he may suppose himself to understand it.3 If there is a problem, here, it is about what “possible” means, but perhaps it is sufficient that the individual does not utterly rule out its occurring. It is to be noted, however, in this connection, that Ayer is anxious to distinguish practical verifiability from verifiability in principle . Thus, in an intriguingly dated example, “There are moun- tains on the other side of the moon” was said to be unverifiable in practice but verifi- able in principle (an example taken from Moritz Schlick). An important question is whether the verification principle is intended not only to tell us whether a statement is meaningful or not, but also to tell us what its meaning is. In effect, rather than in actual formulation, Ayer treats it as doing so and surely this is correct. For if a factually meaningful statement must be a possible aid to knowing what experiences to expect under various circumstances then its meaning must lie in the totality of such aid as it is capable of giving. If there is some residue of purported further meaning it would seem that this could be creamed off as an unverifiable state- ment included within it. That the verification principle is intended to exhibit the meaning of factual proposi- tions is plain from Ayer’s deductions from it concerning the analysis of a whole range of ordinary statements of fact. Thus the verification principle is said to make inevitable a phenomenalist analysis of statements about material objects, since it is only “by the occurrence of certain sense-contents that the existence of any material thing can ever be in the least verified” (1946: 53). It is no good some objector saying that the existence of a physical object is not merely a fact about what sense-contents are available to us, though it is by this that it is verified, for ultimately all that can be verified by facts about sense-contents are facts about sense-contents and the probable truth of what can be inferred from such facts inductively. (See the following section). Ayer, however, like Quine later, eschews talk of meanings as entities, substituting for talk of meanings talk of synonymy (1946: 68) (see QUINE). Analytic or a priori statements The other sort of meaningful statements for Ayer were analytic statements. All genuinely necessary or a priori statements are of this type; thus anything like the synthetic a priori of Kant and others is rejected. 207 T. L. S. SPRIGGE One initial point worth remarking is that, while Ayer is clear that, if a statement is empirically meaningful then so are its contraries and contradictory, his assertion that the only two types of meaningful statements are empirical hypotheses and analytic propositions, taken strictly, implies that this is not so in the case of the latter. If so, while “5 + 3 = 8” is meaningful, the proposition “5 + 3 = 9” is not false, but meaningless. How far this is intended is unclear, since Ayer does, in fact, talk of false mathematical statements. (See 1946: 86.) Ayer’s discussion of analytic propositions (in 1946: ch. IV) starts out from the problem which a priori truth is supposed to pose for empiricism (of which his logical positivism is avowedly a species).