© Michael Lacewing
The project of logical positivism
VERIFICATION AND METAPHYSICS
In the 1930s, a school of philosophy arose called logical positivism. Like much philosophy, it was concerned with the foundations and possibility of knowledge, but approached the subject through the limitations of meaning. Much impressed by the logical analysis of language developed by Russell and the early Wittgenstein, and by the achievements of science, logical positivists developed a criterion for meaningful statements, called the principle of verification, that enabled them to reject as nonsense many traditional philosophical debates. In response to what they saw as the excesses of Hegelian idealism and the schools of thought it had spawned, they wanted to return philosophy once more to being the ‘underlabourer’ of the sciences (Locke).
In his book Language, Truth and Logic, A J Ayer defends this view. The principle of verification states that a statement only has meaning if it is either analytic or empirically verifiable. An analytic statement is true (or false) just in virtue of the meanings of the words. For instance, ‘a bachelor is an unmarried man’ is analytically true, while ‘a square has three sides’ is analytically false. A statement is empirically verifiable if empirical evidence would go towards establishing that the statement is true or false. For example, if I say ‘the moon is made of green cheese’, we can check this by scientific investigation. If I say ‘the universe has 600 trillion planets’, we can’t check this by scientific
investigation in practice, but we can do so in principle. We know how to show whether it is true or false, so it is ‘verifiable’ even though we can’t actually verify it.
Why think these are the only two possibilities for meaning? Metaphysicians, after all, will reject the bald statement that metaphysics must be founded on the experience of the senses. Ayer accepts this. Given that we should accept outright that empirical hypotheses are meaningful, the debate is, then, over the a priori. As the a priori/a posteriori
distinction is exhaustive (there’s no third alternative), he seeks to show that all a priori truths are in fact analytic. And this argument is completed by showing that the purported statements of metaphysics, if not analytic, are literally meaningless.
Strengths of verification
Some logical positivists originally wanted to say that verification must be conclusive, that a statement must be possible to prove true or false. However, this is far too strong, as Ayer argues; empirical hypotheses are only ever more or less probable, never completely certain. So he weakened the claim to verification requires that empirical evidence can raise or reduce the probability that a statement is true.
All statements about what is unobservable, therefore, must be translatable into statements that can be observed in order to be meaningful. This applies as much in science as anywhere. Claims about electrons, for instance, are translatable into what is observable in laboratory conditions. This, Ayer goes on to argue, must in fact be an
God or values, cannot be translated into claims about anything observable, and so are, in fact, meaningless (or more accurately ‘literally’ meaningless – they may have other functions).
Statements about the past provide an interesting case. They are, now, impossible to prove; should they be taken to mean that there is something we can now experience that is relevant to their truth? This would be odd, since the core of the claim is that
something was the case, not that it is now. So Ayer argues that claims about the past are claims that certain observations would have been possible or occurred under certain conditions. This claim as to what someone would or could experience isn’t unusual: I make such a claim when I say what the back of my head looks like when no one is standing behind me.
Philosophy, then, doesn’t give us knowledge of a reality that transcends the investigations of science or is closed to commonsense. It is not a source of speculative truth. The function of philosophy is, instead, to bring to light the presuppositions of science and our everyday claims; in particular, to show what criteria are used to determine the truth of these claims. It does not, however, justify or establish scientific or common-sense beliefs – that requires empirical enquiry (but, pace Descartes, Plato, and indeed Hume, nothing more).
RULING THINGS OUT Ethics
Amongst the claims ruled out as meaningless by the principle of verification are
statements about right and wrong. If I say ‘murder is wrong’, this is not analytic, nor can any empirical investigation show this. We can show that murder causes grief and pain, or that it is often done out of anger. But we cannot demonstrate, in the same way, that it is
wrong. Moral judgements are neither true nor false, because they do not actually state anything.
If ethical statements don’t state truths, and are therefore literally meaningless, what do they do? Ayer argued that ethical judgements express feelings:
If I say to someone, “You acted wrongly in stealing that money”…I am simply evincing my moral disapproval of it. It is as if I had said, “You stole that money,” in a peculiar tone of horror’. (p. 142)
Moral judgements express our feelings of approval or disapproval. Feelings are not cognitions of value, and value does not exist independently of our feelings.
One of the most powerful objections to emotivism, as this theory became known, is that it seems to entail an unsatisfactory view of ethical discussion. If I say ‘abortion is wrong’ and you say ‘abortion is right’, I am just expressing my disapproval of it and you are expressing your approval. I’m just saying ‘Boo! to abortion’ and you’re saying ‘Hurrah! for abortion’. This is just like cheering for our own team – there is no discussion, no
Ayer thought this objection partly false, partly true. It is false because emotivists claim that there is a lot more to ethical discussion – the facts. When arguing over animal rights, say, we are constantly drawing facts to each other’s attention. I point out how much animals suffer in factory farms. You point out how much more sophisticated human beings are than animals. And so on. In fact, says Ayer, all the discussion is about the facts. If we both agree on the facts, but still disagree morally, there is no more discussion that can take place. And this is why the objection is true – but not an objection. When all the facts are in, there is nothing left to discuss.
Emotivists since Ayer have added another layer. The attitudes and feelings we express in our moral judgements don’t occur in isolation. If I disapprove of an action, practically speaking, I must also have similar feelings about similar actions, or my feelings will not provide consistent guidance about how to live. Moral disagreement, then, can be about the relations between different feelings that we have. For example, deciding whether abortion is right or wrong is complicated because there are many feelings involved, sympathy towards the mother, sympathy towards the foetus, feelings about human life, death, and parenthood. It is difficult to work out how these feelings can all be acted upon, and that is why people disagree.
But we may still object that a sense of people’s rationality in weighing up which feelings or attitudes to give up, which to keep, is still missing. We have no sense of one set of attitudes being part of a ‘better life’ than any other. Ayer will respond that the idea of one life being ‘better’ than another is itself an expression of feeling; hence we may still talk this way. Nothing that was ever available in the first place has been lost.
Religion
‘God exists’, and so all other talk of God, also falls foul of the verification principle, claims Ayer. Despite the best attempts of the ontological argument, we cannot prove ‘God exists’ from a priori premises using deduction alone. So ‘God exists’ is not
analytically true. Therefore, to be meaningful, ‘God exists’ must be empirically verifiable. Ayer argues it is not. If a statement is an empirical hypothesis, it predicts our experience will be different depending on whether it is true or false. But this isn’t true of ‘God exists’. It rules nothing empirical in and it rules nothing out. So it is meaningless.
We can object that many people do think that ‘God exists’ has empirical content. For example, the teleological argument argues that the design of the universe is evidence for the existence of God. And on the other hand, the problem of evil takes the existence and extent of suffering to be evidence against the existence of God. Ayer doesn’t explicitly discuss these responses, but the spirit of his response is perhaps captured by Anthony Flew, who argues that ‘God exists’ is only an empirical hypothesis if we can think of experiences that could lead to belief or disbelief in God; most people’s belief in God – and so their assertion that ‘God exists’ – isn’t open to this kind of disconfirmation (the religious believer’s response to the problem of evil is not normally to accept that it decreases the probability that God exists, but rather that it increases the probability that we don’t understand God’s plans).
death makes sense is if there are experiences we can relate it to now. If so, Hick could reply that invoking the counterfactual – what we would experience after our death, if anything – is as legitimate as invoking counterfactuals about the past.
Some philosophers argue that religious language attempts to capture something of religious experience, although it is ‘inexpressible’ in literal terms. Ayer responds that whatever religious experiences reveal, they cannot be said to reveal any facts. Facts are the content of statements that purport to be intelligible and can be expressed literally. If talk of God is non-empirical, it is literally unintelligible, hence meaningless.
REJECTING THE VERIFICATION PRINCIPLE
The verification principle has since been rejected by philosophers as an inadequate account of what it is for a statement to have meaning. A first famous objection is that it renders universal statements, such as ‘All swans are white’ meaningless – because although you could prove this false, no experience will prove it true (there might always be a swan out there somewhere which isn’t white).
This, though, is dealt with by Ayer’s weakening of verification to only require experience to support or reduce the probability of a claim. And, in his discussion of induction, he argues that it is rational to believe, not as a certainty, but as a probability that grows with the range of experience we have, that what we haven’t experienced will conform to what we have. It is irrational to expect a proof.
The main difficulty with logical positivism is that according to the principle of
verification, the principle of verification itself is meaningless. The claim that ‘a statement only has meaning if it is analytic or can be verified empirically’ is not analytic and cannot be verified empirically. But if the principle of verification is meaningless, then what it claims cannot be true. So it does not give us any reason to believe that the claims of ethics are meaningless.
Ayer claims, in his Introduction to the second edition, that the principle is intended as a
definition, not an empirical hypothesis about meaning, though not an arbitrary one. In other words, it is intended to reflect upon and clarify our understanding of ‘meaningful’ uses of words. Since we do use the term ‘meaningful’ in a variety of ways, he wishes only to focus on ‘literal meaning’. Ayer accepts that the verification principle isn’t obviously an accurate criterion of ‘literal meaning’, but that is why he provides arguments in specific cases – ethics, religion, a priori knowledge – which support it. But to this, any philosopher may respond by rejecting both his specific arguments and the verification principle wholesale. It would seem, then, that the verification principle is only as certain as the arguments that are intended to exemplify the consequences of its application. If we do not find those convincing, the principle provides no independent support.
