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Justin Woods

A.J. Ayer and the Verification Farcical


This essay will consist in an exposition and criticism of the Verification Principle, as expounded by A.J. Ayer in his book Language, Truth and Logic. Ayer, wrote this book in 1936, but also wrote a new introduction to the second edition ten years later. The latter amounted to a revision of his earlier theses on the principle.It is to both accounts that this essay shall be referring.

Firstly, I shall expound the verification principle. I shall then show that its condition of significant types is inexhaustible, and that this makes the principle inapplicable. In doing so, I shall have exposed serious inconsistencies in Ayer's theory of meaning, which is a necessary part of his modified verification principle.

I shall also expound Ayer's theory of knowledge, as related in his book. I will show this theory to contain logical errors, making his modified version of the principle flawed from a second angle.

The relationship of this essay with the two prior essays of this series can be understood from Ayer's Preface to the First Edition of his book:

The views which are put forward in this treatise derive from the doctrines of Bertrand Russell and Wittgenstein.

For background interest, Language, Truth and Logic was written after Ayer had attended some of the meetings of the Vienna Circle, in the 1930's.

Friedrich Waismann and Moritz Schlick headed these logical positivists of Vienna. Their principle doctrine can be said to have been founded in the meetings they had with Wittgenstein and their interpretation of his Tractatus Logico-Philosophicus.

Ayer's book expounds and, in his view, improves on the principle doctrine of the Vienna Circle 'the verification principle'. Waismann and Schlick adopted this principle after it was first given to them by Wittgenstein himself.

Waismann recorded the conversation, where Wittgenstein stated:

If I say, for example, 'Up there on the cupboard there is a book', how do I set about verifying it? Is it sufficient if I glance at it, or if I look at it from different sides, or if I take it into my hands, touch it, open it, turn its leaves, and so forth? There are two conceptions here. One of them says that however I set about it, I shall never be able to verify the proposition completely. A proposition always keeps a back door open, as it were. Whatever we do, we are never sure that we are not mistaken.

The other conception, the one I want to hold, says, 'No, if I can never verify the sense of a proposition completely, then I cannot have meant anything by the proposition either. Then the proposition signifies nothing whatsoever.'

In order to determine the sense of a proposition, I should have to know a very specific procedure for when to count the proposition as verified.

He, later in life, told the Moral Science Club in Cambridge:

I used at one time to say that, in order to get clear how a sentence is used, it was a good idea to ask oneself the question: 'How would one try to verify such an assertion?' But that's just one way among others of getting clear about the use of a word or sentence. For example, another question which it is often very useful to ask oneself is: 'How is this word learned?' 'How would one set about teaching a child to use this word?' But some people have turned this suggestion about asking for the verification into a dogma- as if it'd been advancing a theory about meaning.

So, Wittgenstein was merely proposing that the verification of an assertion was one way amongst others to "get clear" how a sentence is used, or how that assertion is used. For, as he tells us in his later philosophy, identifying their uses is how meaning is attributed to expressions.

However, in this essay I shall expose the problems with the verification principle expounded by A.J. Ayer. I shall show why these problems lead the principle to be invalid as a philosophy, and useless as a practical tool in the situations of life it was boasted to have been suited to.


To start the fray, I shall pick on a disturbing piece of wisdom that one runs into at the very beginning of chapter one, "The Elimination of Metaphysics." Here, Ayer wishes to justify the application of the verification principle by showing its use as a tool in the elimination process that would eventually reveal the true purpose and method of philosophical inquiry.

Ayer's 'linchpin' assumption is:

he metaphysician is talking nonsense when he claims to have knowledge of a reality transcendental of the phenomenal world.

If by 'phenomenal world' he means the world of the senses, then he denies his own mind. The mind itself is known, is real in the sense of its contents (thoughts) being real. Yet, it is not a part of the phenomenal, sensed, world.

Therefore, are we talking nonsense when we claim to have knowledge of our emotions, desires, and our self-awareness? And if such knowledge is nonsense, then all the better for us to express it, for nonsense is clearly understandable by these terms.

Surely, then, there is a mental reality, in the above sense, quite distinct from being phenomenal, in the Kantian sense.

All this seems to go without saying, and after applying Ayer's idea of nonsense to our non-phenomenal mental contents, must we conclude that Ayer has 'lost his mind', so to speak?

Of course not! Ayer is merely wetting our appetite; showing us the temper of what is to come later in his book.

I comment on this early, introductory stage because, together with my retort, the spirit of the essay is subtly summarized. Ayer, here, is betraying his bias as an empirical philosopher from the outset, by attributing sense only to phenomenal expressions.

In his book he is merely trying to eliminate nonsense propositions by applying a hand-made law to them, which is not comprehensive enough to include some things which that law refers to but do have sense. This makes it inapplicable and practically useless.

When Ayer asks such a claimant of knowledge transcending the phenomenal from what premises he draws his knowledge, he thereby begins the elimination. He must then, also ask of himself which premises he has for the knowledge that he is happy, sad, confused or, in fact, asking a question mentally (not just vocally).


The verification principle I wish to discuss here is that of the Vienna Circle, as it is expounded by A.J. Ayer in his book Language, Truth and Logic.

This exposition includes a modification by Ayer, and additional points made ten years later on.

Explicitly, the verification principle, as regarded in this essay, is a theory that tries to establish a criterion for meaningfulness.

Although, some may argue that this does not commit the theorist to a theory of meaning, per se, I submit that any theory which involves assertions about the nature of meaning, has tautologically proposed a theory of meaning. Thus, my definition of 'theory of x' includes 'the discussion of the nature of x.'

The aforementioned, verification principle contains assertions that discuss the nature of meaning, yet is originally intended as the answer to Wittgenstein's question, "How would one try to verify an assertion?"

For Wittgenstein, the verification of a proposition was required for a clear understanding of that proposition's meaning.

For Ayer and the Vienna Circle, it was:

The criterion which we use to test the genuineness of apparent statements of fact.

In effect, the verification principle of the Vienna Circle would reveal whether a proposition was meaningful or meaningless. It was a new Humean Fork.

A proposition was meaningful if the conditions of determining its truth or falsehood could be established. A proposition was meaningless if such conditions could not be established.

We inquire in every case what observations would lead us to answer the question, one way or another?

Ayer modified the principle by adding a clause. A proposition could still be meaningful if it could be shown verifiable in principle, in cases where the actual verification was impossible, such as "there are mountains on the farther side of the moon".

This meant putting forward the conditions by which the truth or falsity could be determined.

The other kind of proposition accepted as meaningful was the tautological proposition.

With Hume's Fork in his hand, Ayer declared that if it is not a verifiable proposition and not a tautology, then it is mere pseudo-proposition, factually and literally insignificant, and therefore meaningless.


The first terminological problem we run into with such a principle is the nature of the 'proposition'. What is a proposition? Is Ayer telling us that the only meaningful expressions are putative? Answer: Yes. He is saying just that.

What about questions, commands, suggestions, desires, gestures, expressions containing sarcasm, and intonation? Surely that these types of sentences and expressions are meaningful goes without saying. No one would admit that any of these types of sentences were nonsense in virtue of their form.

As we shall see, later on, they are not significant in virtue of their form, as it is with all apparent expressions. It is not the syntax of a sentence that gives it significance. It is the content. The content should be qualitative: verifiable empirically or tautological.

Ten years after it was written, Ayer comes to the defense of his 'propositions', in the second edition of Language, Truth and Logic, with a rather weak argument given in the appendix.

After making the mistake of admitting propositions to be expressed by some sentences, he summarizes the principle thus:

The principle of verification is supposed to furnish a criterion by which it can be determined whether or not a sentence is literally meaningful. (My Italics)

And to get himself into even more trouble, he continues,

A simple way to formulate it would be to say that a sentence had a literal meaning if and only if the proposition it expressed was either analytic or empirically verifiable. (My Italics)

Instead of trying to show that some statements make no propositions, thereby avoiding the problem of making "Hey, Jude!" into a truth-valued proposition, he persists with the idea that all sentences propose something.

His argument for this, as found in the updated appendix, goes as follows.

Ayer states later on that he has tried to avoid the problem of any sentence having to be meaningful in virtue of its proposition having a truth value, by speaking of putative propositions, in which a sentence purports something, and can be true or false.

A few lines later, he admits that not all sentences are putative (His theory of meaning jumps back and forth, from 'some' to 'all', and is clearly unreliable).

The problem is now, how do we know when a sentence is purporting something? Is it not true that all sentences admit a truth indirectly? If I say, "Go to your room!" to a boy, am I not implying that there is a 'room' to 'go to'? Is there not, therefore, a hidden proposition in many sentences that are thought not to be putative?

If this is the case then we shall need another criterion to determine which sentences these are. And such a criterion may have too much room for interpretation; am I speaking of a metaphorical 'room'?

Perhaps this is why Ayer is not satisfied with the term 'putative'. He states in the second edition, that:

the use of words like 'putative' and 'purports' seems to bring in psychological considerations into which I do not wish to enter.

Ayer, in his second edition, is clearly not confident about his own argument, but only alludes to its abandonment by offering these weak arguments as valid replacements and then rejecting them himself, as is shown above.

His next argument is even more absurd: to apply the verification principle directly onto all sentences, whether putative or not.

As we have seen this leads us to accept the oddball fact that questions, commands, and suggestions are literally meaningless if they are neither true nor false. In addition, whether they contain a hidden putative proposition must be decided by another criterion that has not yet been developed. Even so, if such a criterion was developed and applied, too much room for interpretation would result due to the psychological contingent of words such as 'putative' and 'purport'. For 'purport' relies to heavily on a condition of the mind — a mental state. A feeling of assertiveness is a different species from asserting something. One relies on a state-of-mind, an attitude or belief; the other states the case, as it is given and not as it is desired to be.


One of the reasons why the verification principle fails to be applicable is its erroneous theory of meaning. The principle considers there to be only two types of significant expression that are neither meaningless nor nonsense:

  1. Literally significant expressions are those that express either a tautology or a proposition, which is capable, at least in principle, of being verified.

  2. Factually significant expressions are such, if, and only if, we can know how to verify the proposition which it purports to express. Moreover, what observations would lead us under certain conditions, to accept the proposition as being true, or reject it as being false.

Neither of these types of significant expressions allows for moral, religious or even mental significance. I am saying here that there are some expressions, which are significant, that do not belong to either of Ayer's categories. The error of Ayer's theory of meaning is that it is not exhaustive. In other words, the options we are given are less than what are available.

There are more than two types of significant expression, and significance does not consist in only factual content and semantics.


Gestures, commands, requests, inclinations, verbal minims... the list of types of expressions of thought that have significance to us is very long. They are significant in virtue of their 'signifying', or standing for, x.

The verification principle does not allow for these, as though only the objects of sense experience and tautological elements can be signified. The verification principle states that such expressions are not significant, and therefore nonsensical and meaningless. I will now show that this is not the case, thereby proving the theory of meaning, which is essential to the verification principle, as erroneous and making the principle inapplicable because it is not exhaustive.

The assumption, made by Ayer and the Vienna Circle, is that "sentences are either tautological or empirical in their significance." However, this is not exhaustive.

Ayer, himself, does admit that ethical statements, although having not expressed a literally significant proposition, are not therefore nonsense, since they do possess another kind of significance:

The sentence expressing it may be emotionally significant to him; but it is not literally significant.

It is this admission that undoes all his work hitherto. If there are other types of significance then he admits that his theory of meaning is not exhaustive. This leads him to admit further that the verification principle is applicable to only some significant expressions, annulling the 'either or' that so willingly attempted to eliminate expressions of ethics, religion and metaphysics.

It may be argued that the above admission, being the basis for Ayer's emotive theory of evaluative discourse, is an unmasking move to show that supposedly factual statements are merely expressions of feeling- emotive expressions.

If a statement is significant in virtue of its signifying an x, where x is that which the statement refers to, then if x is a feeling, rather than a thought, the significance of feelings is possible. The significance of feeling in language could be called an emotively significant statement.

Ayer's mistake was in thinking that meaning can only be attributed to expressions that represent an empirical fact or a logically tied set of concepts, as are found in the tautology.

So, what makes other expressions significant? You could ask, 'In what sense are these other sentences significant?' Well, they are significant in virtue of your ability to understand them. If you understand a sentence, then your understanding is that to which the sentence refers. However, this rules out false sentences, which may be insignificant but disguised by the fact that you cannot understand all sentences; some genuine sentences are difficult to understand.

Let us look at a common target of the principle: ethical expressions.

Ethical statements such as 'Murder is wrong' are significant by the fact that we understand them. However, they are not significant in the factual sense, but the emotive sense: they are emotively significant.

We do not wonder what anyone means when emotive statements are made. We do not hear it as a muddle of incomprehensible speech, and wonder whether such noises 'signify' anything. We understand that the person is expressing a certain attitude or feeling about the subject of murder. The person is stating, implicitly, that they would like no one to conduct such an act, and would not like to themselves.

Sentences such as these signify feelings and attitudes. They do not have truth-value, they cannot be empirically tested, and they are not meant to be. Ayer may also assert this, but he goes on to suggest that they are also meaningless.

They are not meaningless. They express a different species of thought, an emotive thought. The thought is signified by words. The words have meaning in themselves. This is the criterion for significance.

Therefore, moral sentences are significant when they express a feeling or attitude about certain behaviour. The reason why verificationists like Ayer want to reject them is because they don't fit into there tight little theory; they cannot be verified. If it were possible to verify feelings, then statements about such would become meaningful.


We have already discussed the major themes put forward by the second edition in the many references to them hitherto. However, we have not yet looked at a further argument Ayer has in defense of his theory of meaning.

The argument goes like this:

Up until now, Ayer has wanted to avoid denying the possibility of sentences that carry meaning without propositions. Therefore, he puts forward the following, as a second attempt:

The solution that I prefer is to introduce a new technical term; and for this purpose I shall make use of the familiar word 'statement'.

So, now Ayer has pulled a U-turn and allowed expressions to be significant without being nonsense, by avoiding the attribution of literal meaning to all sentences. The term 'statement' is that sentence which, although does not contain a truth-valued proposition, does express something in its significance. Its significance is held in virtue of its being 'indicative'.

Indicative sentences- now 'statements'- have the option of holding literal meaning, in the case of the proposition, or not.

Not holding literal meaning, by definition, they remain significant.

This, to me, is obviously a complex attempt at escaping the fact that verification principle is not applicable. What it does not apply to are forms of significance that cannot be grouped into the empirical/tautological pigeon-holes that Ayer has created.

Ayer is now logically tied to admit that there are other meaningful expressions that are signified in sentence form, and have no explicit truth-value (i.e. the proposition). This is of course his 'statement'.

To say that there are 'indicative sentences', which may express a meaning that has no truth-value, is to admit of other forms of significance, to admit that the verification principle is limited in its application.

However, my main contention with the principle is not its problem with terminology use, or its theory of meaning. I am concerned with the empirical features verification.


I would now like to look at the empirical features of the verification principle. I shall show that statements of observation, empirical, and synthetic alike, may not necessarily require the prerequisite of a truth-value in order to have meaning.

I shall then show that Ayer's theory of sense content is redundant.

The verification principle requires thus:

that a sentence 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.

Firstly, two problems:

  1. In what would these observations consist? Propositions of factual significance are surely assertive expressions, which reflect, or stand for, the data of particular senses. However, why place a truth-value on such an expression? If I see green grass, and state, "this grass is green" am I not stating something that is not held, by myself or anyone else who is not a philosopher, to be dubious?

  2. Is it not that my statement is nothing more than the expression of what my senses tell me they detect? If this is so then the notion of applying a truth-value to such a statement is invalid. For surely, when I make a statement that expresses an observation it will always be true of my senses. It will be true in the sense that I am not lying to myself, but "truth" still seems an inappropriate term for such statements. Truth-value, therefore, does not apply to expressions signifying sense-data.

Ayer's 'truth' is meant in the sense that my statement of observation, my proposition having factual meaning, could be verified as to whether it was indeed an observation. However, in what would the verification consist?

Would this not be another statement of observation by which to compare mine with? For surely if I state that "green men are on the far side of the moon", and an observation of these green men at such a place would lead to the same species of statement, "yes, there are green men on the farther side of the moon", warranting, itself, verification. Is this how Ayer determines meaning?

So, by Ayer's account we would either continue an infinite regression of verifications of the same statements, or take the second verifying statement as the deciding factor of the first statement's meaning, when both statements express the same thing; their reference is identical.

If we do admit truth-value of sense-data, can we trust our senses? How do we tell a real observation from an illusion?

To answer these questions, Ayer requires a theory of knowledge, and it is this theory that falls apart after close inspection.

First, I shall outline the theory. Then I shall show its principle theses to be invalid.

The result will be that the factual significance of Ayer's verified sentences will always contain the possibility of being factually wrong. They may be meaningful, in virtue of their truth-value, but you would never know whether they were correspondingly true or false.

So how does Ayer determine the validity of his empirical propositions?

Empirical propositions... may be confirmed or discredited in actual sense experience.

It is admitted that no empirical proposition is certain, but that is not what we are concerned with here. We are concerned with knowing whether an empirical proposition is actually being experienced during its verification.

How do we know that the physical manifestation of an empirical proposition is actually being represented, and not an illusion or drug-induced delusion?

To answer this, we return to the question, "What is the criterion by which we test the validity of an empirical proposition?"


we test the validity of an empirical hypothesis by seeing whether it actually fulfills the function it is designed to fulfill.

Ayer is an empiricist. When it comes to the factual content of a proposition, Ayer takes the position that this content consists in terms of sense content. The physical object of the proposition is not itself known; we are only privy to a second-hand knowing by means of our senses. Our senses 'see' the real object, and we 'know' what our senses give us.

We define a sense content not as the object, but as a part of a sense experience. And from this it follows that the existence of a sense content always entails the existence of a sense experience.

So, when I see a table and state such, my assertion entails the sense contents from which the term 'table' is logically constructed. The sense contents being so entailed allow my assertion to be a proposition containing factual content, and therefore meaningful.

However, since the sense contents are not the objects themselves, the verification of expression containing them leads to the truth or falsity coherently, rather than correspondingly. The truth-value of factually or literally significant propositions is established by appealing to its logical compatibility with other sense content containing propositions. Since the reality of sense experiences is subjective, their truth must also be subjective.

By admitting that the objective world, which we cannot know but by the senses, is never expressed by propositions, but only indirectly via the sense contents, we must admit that the verification of the objective world can have no truth-value attributed to it.

Nevertheless, the verification principle demands that an empirical hypothesis be testable, in principle or practice. Once more, this test would only lead to more expressions containing 'sense contents'. What is more, such a test could only consist in the comparison of one subjective set of propositions with another.

In effect, the verification of an empirical hypothesis would establish coherent truth, since correspondent truth is transcendental. Therefore, the phenomenology of the verification principle is incompatible with Ayer's empiricism.


The verification principle was a method of establishing the meaning of certain expressions. It was then turned and used to eliminate the whole of metaphysics, which also took with it ethics, aesthetics and religion. It seemed that nothing was left but the obvious world of facts or the nothing world of tautologies.

In the end, the verification principle helped destroy not just speculative philosophy, but speculation itself. The world of philosophy is a far different place today, thanks to the influence of A.J. Ayer and the Vienna Circle. Their influence, in my view, dominates mainstream philosophy, in its academia, its publications, associations, and societies.

Their ideas changed the way we think about philosophy — about its nature and purpose. The texts written in their day are the textbooks of today.

The language of fact and tautology rule, sixty years on.

I wish that I could have written from a more speculative angle, but the verification principle seemed to come with its own problems built in.

Although, philosophy has been deemed by Ayer to not be a source of speculative truth, I hope that I have shown that it is speculation, and not just logic and correct language use, that inspires the mind of the philosopher.

If we are to believe, as Ayer does, that philosophy should consist in nothing but logical analysis, then it is hard to see how philosophy could have come about at all. Some philosophers say that it is not the business of philosophy to concern itself with metaphysics, ethics, aesthetics, religion, or any speculation. They miss the point that it is themselves who expend such considerable amounts of literature in order to say so.

By trying to convince us that Plato, Nietzsche, and the hordes of nonsense philosophers in between, had got it all wrong, these very philosophers make the broadest and grandest of speculations themselves.