Summary |
Knowability is the concept that figures in epistemic
theories true---for instance semantic anti-realism claims, necessarily, every
truth is knowable in principle. Michael
Dummett argues for the position along the following lines. Given that meaning is fully manifestable in
use and that grasp of meaning involves knowing truth conditions, the fully competent
user of the language is in principle able to recognize that a proposition is
true when it is. The most important
alleged consequence of the position is that classical logic is not
unrestrictedly valid. For the
unrestricted principle of excluded middle together with semantic anti-realism
(and some modest auxiliary assumptions) entails strong decidability---i.e., that, unrestrictedly, every proposition or
it’s negation is knowable in principle. And that conclusion is false, not known apriori, and unacceptably immodest. Therefore, exclusively classical principles are false, not known apriori and unacceptably immodest.
Most recent discussion centers around Fitch’s paradox of knowability. The paradox threatens to collapse semantic
anti-realism into an implausible idealism----the theory that, necessarily, every truth
is (at some time) known. Since an
important selling point of moderate anti-realism is that it distances
itself from naïve idealism, the collapse is unwelcome to the anti-realist. But the paradox is not just a problem for
anti-realists, because the result threatens to erase the very logical distinction
between semantic anti-realism and naïve idealism. Even those of us who have
not been seduced by anti-realism may still want to distinguish it from (and treat it as logically weaker than) idealism. |