Rudolf Carnap and A. J. Ayer
I received an offline note about Carnap and Ayer and the
implications of their version of logical positivism to
the various issues of logic and ontology that we have been
discussing. Following is the question:
> I found a copy of the 1946 edition of Alfred Jules Ayer's
> "Language Truth and Logic" (Dover), which looks pretty
> interesting. It states on the back cover:
First published in 1936, this first full-length presentation
in English of the Logical Positivism of Carnap, Neurath, and
others has gone through many printings to become a classic
of thought and communication. It not only surveys one of the
most important areas of modern thought; it also shows you how
to apply analytical methods to your own field of work and
dispel the confusion that arises from imperfect understanding
of the uses of language. [...]
> Without wanting to take up too much of your time, what in a
> nutshell was your criticism of Carnap, such that when I read
> this I'll be looking out for the issues you've raised?
Following is my response.
John Sowa
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Before I say anything critical about Carnap, let me say
that I learned a great deal from his books, I admire him
very much for his work on logic, ontology, and related
issues, and I highly recommend his books as very good
treatments of many topics related to logic & ontology.
Re Ayer's Language Truth & Logic: That is an enthusiastic
treatment of logical positivism written by young Englishman
who visited the Vienna Circle and came back to preach the
exciting new religion he had just adopted. That book became
a best seller (as philosophy books go), and I, along with many
of my fellow students, was very impressed when I read it at
MIT in 1960. But as Ayer matured, he realized the limitations
of that approach and admitted that it was a young man's book
that had to be seriously qualified and revised.
To use Peirce's terminology, the fatal flaw of logical
positivism (and Russell's related verision of logical atomism)
is that it ignores Thirdness and tries to explain everything
(including human language and behavior) in terms of Firstness
and Secondness.
In non-Peircean vocabulary, the logical positivists either
ignored purpose, intention, meaning, and value or tried
to replace them with pale imitations derived from purely
observational statements about what exists. As Peirce would
say, those concepts can only be defined in terms of irreducible
triadic relations that involve a mind-like interpreter. That
mind need not be human. Animals (and perhaps robots) could
play the third role in those relations.
Wittgenstein wrote his first book after spending three years
studying with Russell and working with him on the development
of logical atomism. (W's Tractatus is actually a better
presentation of logical atomism than anything that Russell
wrote on the topic.) But after spending a couple of years
teaching elementary school in an Austrian mountain village,
Wittgenstein realized that people (especially children)
don't think that way. There is more to life than what can
be derived from purely observational statements. I recommend
Ray Monk's biography as an excellent presentation of how
Wittgenstein's ideas grew and developed over the years.
In his later work, Wittgenstein explicitly repudiated his
earlier work, which he still believed was important. He said
that he would like his later book _Philosophical Investigations_
bound with his earlier book so that readers could compare the
two. Ayer didn't repudiate his earlier work as thoroughly as
Wittgenstein, but he did change his views quite a bit (as did
Carnap, who added many qualifications to his earllier work).
I believe that all three of them (Wittgenstein, Carnap, and
Ayer) would have benefitted from studying Peirce. In fact,
there is some evidence that Wittgenstein was indirectly
influenced by Peirce through his discussions with Frank
Ramsey; see the paper by Jaime Nubiola on that point:
http://members.door.net/arisbe/menu/library/aboutcsp/nubiola/scholar.htm
Scholarship On The Relations Between Wittgenstein And Peirce