Full Idea
Frege was strongly in favour of taking truth to attach to propositions, which he called 'thoughts' and regarded as being expressed by sentences.
Gist of Idea
Frege was strongly in favour of taking truth to attach to propositions
Source
report of Gottlob Frege (On Sense and Reference [1892]) by Michael Dummett - Truth and the Past 1
Book Reference
Dummett,Michael: 'Truth and the Past (Dewey Lectures)' [Columbia 2004], p.1
A Reaction
Sometimes it is necessary to know the time, the place, and the speaker before one can evaluate the truth of a proposition. Not just indexical words, but the indexical aspect of, say, "the team played badly".