Full Idea
The maxim that 'most of a speaker's beliefs are true' as an a priori principle governing radical translation seems to me to go too far; first, I don't know how to count beliefs; second, most people's beliefs on some topics (philosophy) are probably false.
Gist of Idea
You can't say 'most speaker's beliefs are true'; in some areas this is not so, and you can't count beliefs
Source
Hilary Putnam (Meaning and the Moral Sciences [1978], Pt Three)
Book Reference
Putnam,Hilary: 'Meaning and the Moral Sciences' [RKP 1981], p.101
A Reaction
Putnam prefers a pragmatic view, where charity is applicable if behaviour is involved. Philosophy is too purely theoretical. The extent to which Charity should apply in philosophy seminars is a nice question, which all students should test in practice.