Willard Van Orman Quine

246 daniel isaacson
Further along Carnap expresses his commitment to conventionalism,
which, though tempered by pragmatism, is unacceptable to
Quine:
The syntactical investigation of a system which is already given is indeed
a purely mathematical task. But the language of science is not given to us
in a syntactically established form; whoever desires to investigate it must
accordingly take into consideration the language which is used in practice in
the special sciences, and only lay down rules on the basis of this. In principle,
certainly, a proposed new syntactical formulation of any particular point of
the language of science is a convention, i.e. a matter of free choice [emphasis
added]. But such a convention can only be useful and productive in practice
if it has regard to the available empirical findings of scientific investigation.
(p. 332)
Quine rejects the possibility of standing outside science, which he
came to see as the impossible vantage point required for Carnap’s
project of logical syntax, of giving “syntactical rules rather than
philosophical arguments” (Carnap 1937, 52). For Quine, “Scientific
language is in any event a splinter of ordinary language, not a substitute”
(SLS 228).
The differences between Quine and Carnap turn ultimately on rejection
versus acceptance of the analytic-synthetic distinction. Tenability
of the distinction licences the sharp division between philosophy
and science. Rejection of the distinction, gradualism (PL 100), leads
to Quine’s view that philosophy is continuous with science. It also
is constitutive of what empiricism itself is taken to be. Tenability of
the distinction allows a disjunctive formulation: Knowledge of a sentence
in a given language is either purely based on knowing that language
or based ultimately on sensory experience. Quine’s “more thorough”
empiricism dispenses with the first disjunct. 32 Carnap’s form
of empiricism allows the possibility of establishing mathematics as
analytic so that empiricism can account for mathematics and logic
without having to claim that mathematical and logical truth rests ultimately
on sensory evidence. Untenability of the analytic-synthetic
distinction means that mathematical and logical truth must rest ultimately
on sensory evidence, so that mathematics has empirical
content.
Quine rejected the analytic-synthetic distinction because it could
not, in his view, be established on an empiricist basis. For Quine,
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