Logical Positivism Revisited

In a Nutshell

The Vienna Circle

The story has its origins in 1920s Vienna. A group of philosophers, mathematicians and scientists gathered there around a charismatic academic called Moritz Schlick. This so-called ‘Vienna Circle’ believed that philosophy as we knew it was redundant.

Their key idea was the so-called verification principle. A statement is meaningful only if it can be verified by empirical observation or is true by logical definition. But claims that couldn’t be tested against the world or couldn’t be established by logic weren’t merely false but were meaningless.

Enter Ayer

The man who did most to bring these ideas to Britain was a 24-year-old philosopher, Alfred Jules Ayer, known as Freddie. Ayer had visited Vienna and returned to publish Language, Truth and Logic in 1936. It became one of the most influential works of twentieth-century British philosophy.

There was, however, a problem, and it wasn’t going to go away. Can the verification principle be verified? Can we verify it empirically? There is no experiment we can perform that establishes that only empirically verifiable statements are meaningful. Is it true by definition? Again, apparently not.

So what status does the verification principle itself have? By its own criterion, it seems to be meaningless. And the difficulties didn’t end there.

Popper, Wittgenstein and Quine

What distinguished a genuinely scientific claim, according to Karl Popper, was not that it could be verified but that it could, in principle, be falsified.

No number of observations of white swans can finally prove that all swans are white, but a single black swan can prove that they aren’t.

Ludwig Wittgenstein argued that language was considerably more varied than the positivist account allowed.

W.V.O. Quine attacked the supposedly clear distinction between statements true by definition and statements established through experience.

The problems were mounting.

Ayer’s verdict

Ayer was asked in his later years what he regarded as the principal defects of logical positivism. “I suppose”, he replied, “the most important of the defects was that nearly all of it was false.”

But was logical positivism really a complete failure? Well, the verification principle didn’t survive, and the questions the positivists tried to eliminate returned. But philosophy didn’t simply return to where it had been before. The positivists demanded clarity and were suspicious of impressive-sounding claims for which no adequate justification could be given. Modern philosophy retained those instincts even after abandoning the verification principle itself.

Freddie

And what of Freddie?

There is a wonderful story about Ayer attending a party at which he encountered heavyweight boxing champion Mike Tyson in an altercation involving the young Naomi Campbell. Tyson reportedly demanded to know whether Ayer realised who he was.

Ayer was all too aware but replied that he was the former Wykeham Professor of Logic, that they were therefore both pre-eminent in their respective fields, and suggested that they discuss the matter rationally. Wrongfooted by Freddie, Tyson relented and the matter came to an amicable conclusion.

Later in life Ayer also had a near-death experience that briefly caused the lifelong atheist to reconsider some of his assumptions, although he subsequently retreated.

I have my own, rather less philosophical, memory of Freddie Ayer.

One Saturday afternoon I saw him roar past me on the M25, driving at considerable speed and surrounded by a haze of cigarette smoke.

Logical positivism may have run out of road. Freddie Ayer never seemed in much danger of doing so.