A book which has hovered in the background of philosophical discussion for several decades is Ayer’s Language, Truth and Logic. According to the blurb on my Penguin copy it is “the original English manifesto of Logical Positivism. It remains the classic statement of this form of empiricist philosophy and still retains its interest after more than thirty years.” It was first published in 1936, a second edition appeared in 1946, and I am using the Penguin reprint of 1976. In this the Introduction offers further explanation of several points but the author confirms that for the main text “I still believe that the point of view which it expresses is substantially correct.”
I want to take up the feature which has earned the book much of its reputation; the principle of verifiability, This is how the author formulates it:
We say 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 circumstances, to accept the proposition as being true, or reject it as being false. (p.48)
This statement speaks of unqualified verification, implying that conclusive verification is required, and this, Ayer says, is going too far. No general statement, e.g. “all men are mortal,” can ever be conclusively verified by observation, and neither can any statement referring to the remote past. To require the possibility of conclusive verification before accepting any sentence as factually significant would be to condemn all general sentences, and all those referring to the remote past, as meaningless, and this Ayer is not willing to do. He therefore modifies this requirement:
Accordingly, we fall back on the weaker sense of verification. We say that the question that must be asked about any putative statement of fact is not, would any observations make its truth or falsehood logically certain? but simply, Would any observations be relevant to the determination of its truth or falsehood? And it is only if a negative answer is given to this second question that we conclude that the statement under consideration is nonsensical. (p.152)
He does not limit himself to saying that some meaningful propositions are incapable of conclusive verification, he says that no proposition can be conclusively verified:
no proposition is capable, even in principle, of being verified conclusively, but only at best of being rendered highly probable… (p.179)
This is where the difficulties of Axer’s argument begin to appear. For if, as he says, no proposition can be conclusively verified, this must apply to his own earlier propostion quoted above, the one asserting that no proposition may be regarded as being factually significant unless it is capable of being at least partially verified. On his own showing this preposition can be no more than highly probable; after all his careful work there remains, according to that work, some possibility that propositions completely incapable of empirical verification may be factually significant. He himself demonstrates that his principle of verification cannot be conclusively verified.
That is one difficulty; a more serious one lies behind it. If we accept the proposition that no proposition can be conclusively verified, it follows that that proposition itself cannot be conclusively verified. On his own showing, the most that Ayer can ever be entitled to say is that it is highly probable that no conclusion can be conclusively verified. But he puts it as an unqualified assertion, without the “highly probable,” and thereby shows himself to be assuming at least the possibility of conclusive verification. He is maintaining two incompatible hypotheses. Firstly, that no proposition is capable of being conclusively verified. Secondly, that one proposition (the one asserting that no proposition can be conclusively verified) can be conclusively verified.
And he himself tells us that maintaining incompatible hypotheses is “the one thing we may not do.” (p.126)
Ayers says in his Preface that the views he puts forward derive from the doctrines of Russell and Wittgenstein. I suggest it may be significant that the self-contradiction we have found in Ayer’s work has a parallel in that of Russell. Speaking of the Principia Mathematica of Russell and Whitehead, Harold Walsby points out:
The authors, however, scuttle themselves from the very start of Chapter Two of the Introduction (specially designed to explain the theory) with the following gem:
‘We shall, therefore, have to say that statements about “all propositions” are meaningless.’
Which, of course, is simply another way of asserting: “All propositions about ‘all propositions’ are meaningless.” There are numerous other assertions of the same kind. Such assertions are, indeed, unavoidable in propounding the theory, which circumstance renders it self-refuting from the start. Thus, when ushered into the world by its authors, it was already still-born. To found a theory designed to avoid self-contradiction upon such assertions as You must never say “You must never say”‘ surely touches the low-water mark in the history of logic?” (The Paradox Principle and Modular Systems Generally p.16)
I have singled out Ayer as Walsby singled out Russell, but whatever Walsby may have thought about Russell, my comments on Ayer’s work are not intended to suggest that he is necessarily behind other thinkers in the matters to which I have called attention. On the contrary, he is ahead of many of them; he has developed his thinking to the point where self-contradictions, usually below the surface, merely implicit, are brought out where they can be clearly seen and directly dealt with. Language, Truth and Logic is a valuable book, stimulating and provocative; there is far more in it than appears from these brief comments. But we have to say that Ayer has not achieved his declared object, he has not succeeded in providing “a definitive solution of the problems which have been the chief sources of controversy between philosophers in the past.”
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The French have a proverb saying, in effect, that the more things alter the more they stay as they are. It doesn’t apply only in France:
The Old: In 1882 (actually 1884, but let’s make it a round century) Punch printed a cartoon of an Englishman speaking to a Frenchman. This was the caption:
It’s all very well to turn up your nose at your own beggarly Counts and Barons, Mossoo! But you can’t find fault with our nobility! Take a man like our Dook o’ Bayswater, now! Why, he could buy your foreign Dukes and Princes by the dozen! And as for you and me, he’d look upon us as so much dirt beneath his feet! Now that’s something like a Nobleman, that is. That’s a kind o’ Nobleman that I, as an Englishman, feel I’ve got some right to be proud of!
And the New: One hundred years later, in 1982, Jill Tweedie writes in the Guardian, (22 Feb 82):
… of course what we really admire, of course what makes us roll over on our backs and wave our paws in the air is the very idea of a buccaneer businessman like Freddie Laker and when, after absolute disaster at our expense, he teams up with another businessman like Tiny Rowlandson – the original ‘unacceptable face of capitalism’ – we can hardly conceal our ecstasy. Mr. Laker has only to mention the words ‘People’s Airline’ … and we hasten to delve into our hard-earned savings and send him supportive cheques.
from Ideological Commentary 11, March 1982.