I want to talk about the final reading for the version of Introduction to Philosophy that I taught towards the end of my career: three chapters from A.J. Ayer’s Language, Truth, and Logic, which originally was published in 1936 and was responsible for bringing logical positivist ideas from the European continent to the English speaking world.

Because the work is somewhat technical – and certainly is experienced that way by a general education audience – and the last thing students had read was J.S. Mill’s Utilitarianism, I spent an entire lecture just on background and especially on the question of the positivist’s targeting of metaphysical statements. Without this frame of reference, the apparatus of the Verification Principle appears motivated by nothing more than a narrow scientism, so I took some time to explain to my students the logical positivists’ concern over the role played by metaphysical and mystical statements coming out of 19th century Romantic nationalism in the fascist politics that were spreading across the continent in the early 20th: “Blood moves the wheels of history” and “The folk is rooted in the soil and bound together by its common blood” were just two of several examples that I gave of the sort of thing I wanted them to think about. Of course the positivists also were motivated by a more general empiricist anti-metaphysical attitude, in the spirit of Hume’s famous statement from the Enquiry, which I also discussed with my students: 

If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matters of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion

The Verification Principle

I explained that the anti-metaphysical strategy employed by the positivists and by Ayer involves demonstrating that metaphysical statements are meaningless. Now, for those who have studied philosophy for some time, saying this would be a sufficient prelude to introducing the Verification Principle (VP), but I was concerned that students might find the notion of meaninglessness involved obscure, so I spent some time on two different ways in which a sentence might be meaningless: (1) if it is ungrammatical or ill-formed, such as “Uncle purple rains Wednesday to”; and (2) if it involves bogus – in the sense of non-existent – words, like Lewis Carroll’s “Twas brillig and the slithy toves did gyre and gimble in the wabe,” from Jabberwocky. 

Ayer proposes a third criterion for meaningfulness and that brings us to VP, which says: A sentence is meaningful if and only if one could, in principle, explain how one would go about showing it was true or false.

Notice that even sentences which are not currently verifiable can satisfy this criterion: “There are caves on Pluto” is not a sentence that we can verify currently, but we know how one would verify it. However, sentences like “God is eternal love” and “The folk is rooted in the soil and bound together by the bond of its common blood” are not like this, for not only are we not currently capable of verifying them, we could not even explain how one would go about doing so.

Mathematical Statements

It might appear obvious that VP is far too narrow a criterion for linguistic meaningfulness, insofar as there seem to be perfectly ordinary sentences that clearly are meaningful, while not being verifiable in the manner described by Ayer. “Three plus two equals five” is a sentence that is obviously meaningful – I suspect every person reading this both understands and believes it – and yet, it is not empirically verifiable. One may have learned the truth of the statement by counting pebbles or blocks, but no amount of such counting could ever confirm or disconfirm it.  As I pointed out to my students, if they counted the pebbles and got “six,” we wouldn’t conclude that “Three plus two equals five” had been disconfirmed. Rather, we would insist that  they had counted wrong, and I pointed out that we would say the same thing even if thirty people had counted them and got “six” as a result.

So what does Ayer do with mathematical statements? They clearly aren’t meaningless, and yet they seem to fail the verification test. Ayer’s answer here is interesting, but is no longer considered viable today, insofar as it depends on a now-defunct program.

Ayer argues that mathematical sentences are in fact analytic, by which he means that they are logical truths. ‘Three plus two’ and ‘five’ are alleged to be synonymous, so even though mathematical sentences are not empirically verifiable they are, in a sense, linguistically verifiable, which explains their meaningfulness.

Our knowledge that no observation can ever confute the proposition ‘7 + 5 = 12’ depends simply on the fact that the symbolic expression ‘7 + 5’ is synonymous with ‘12’, just as our knowledge that every oculist is an eye-doctor depends on the fact that the term ‘eye doctor’ is synonymous with ‘oculist’. And the same explanation holds good for every other a priori truth.

Of course, this depends on being able to demonstrate that mathematical statements are in fact truths of logic, a claim that was made by those pursuing the logicist program in the late 19th and early 20th centuries. The overwhelming consensus is that this program was a failure, which, if correct, means that Ayer’s way of handling mathematical statements will not work, and he is left with the problem of their meaningfulness unresolved.

Moral Statements

The other great challenge to VP lies in the area of moral discourse. Sentences like “Snatching that guy’s wallet is wrong” are clearly meaningful – again, I think it safe to assume that everyone reading this both understands it and will agree with it – but they are not verifiable, either empirically or linguistically. There are no observations that are going to confirm or disconfirm the wrongness of the wallet-snatching, and the truth or falsity of the sentence cannot be determined just by examining the meanings of the words.  

Ayer takes this objection seriously and makes a serious effort at responding to it, one that has had legs far beyond the Verification Principle itself in the form of ethical Emotivism. What he says is that moral terms are actually performatives: they don’t refer, but rather do various things – approve, condemn, command, plead, and the like. Thus, when we say, “Snatching that guy’s wallet is wrong,” what we really are saying is something like “Don’t snatch that guy’s wallet!” or “Snatching that guy’s wallet, BOO!” The verificationist can thus avoid being saddled with the view that moral statements are meaningless, because he doesn’t think they are statements at all, but rather expressions of feeling, commands, etc., whose meaningfulness is not a function of their verification conditions.

The main difficulty with this move is that if correct, it should follow that there can be no moral disputes, as only statements – sentences that express propositions – are disputable. If I like vanilla ice cream and you can’t stand it, we don’t have a dispute, as evinced by the fact that the difference between us cannot be settled by appeals to evidence or arguments. Consequently, if moral sentences are not in fact statements but expressions of feeling or commands they too cannot be matters of dispute. The trouble, of course, is that they are. More than that, they are some of the most heavily disputed of all the things we say.

Ayer’s take on this is ingenious and persuasive, to a point. Often, a conflict in attitudes or feelings is grounded in disagreement over relevant facts. Years ago, when the issue of gay marriage was being debated, those on the pro- and anti-sides certainly had conflicting attitudes, but they also disagreed substantially on the facts: specifically, as to whether allowing gays and lesbians to marry would do damage to the institution of marriage. It seems reasonable to think, moreover, that had there not been these sorts of factual disagreements, there likely would have been less conflicts in attitudes. Of people growing up, living, and working in the same society it seems reasonable to expect similar attitudes in reaction to similar facts.  

When someone disagrees with us about the moral value of a certain action or type of action, we do admittedly resort to argument in order to win him over to our way of thinking. But we do not attempt to show by our arguments that he has the ‘wrong’ ethical feeling towards a situation whose nature he has correctly apprehended. What we attempt to show is that he is mistaken about the facts of the case. We argue that he has misconceived the agent’s motive: or that he has misjudged the effects of the action, or its probable effects in view of the agent’s knowledge; or that he has failed to take into account the special circumstances in which the agent was placed. Or else we employ more general arguments about the effects which actions of a certain type tend to produce, or the qualities which are usually manifested in their performance. We do this in the hope that we have only to get our opponent to agree with us about the nature of the empirical facts for him to adopt the same moral attitude towards them as we do. And as the people with whom we argue have generally received the same moral education as ourselves, and live in the same social order, our expectation is usually justified.  (p. 70)

But this analysis is only somewhat persuasive. For one thing, it’s not clear that every moral conflict sits astride a dispute over facts, and for another, we’ve all had experiences in which no amount of agreement on the facts eases a conflict in values, even with people who are from our own communities or even our own families. And so while of all the elements of Language, Truth, and Logic, Ayer’s Emotivism has remained relevant the longest, there are a number of problems that strongly tell against its being a satisfactory treatment of moral language and discourse.