Full Idea
Truth-makers cannot be the designata of the sentences they make true, because sentences with more than one truth-maker would then be ambiguous, and 'a' and 'a exists' would have the same designatum.
Gist of Idea
Truth-makers cannot be the designata of the sentences they make true
Source
Mulligan/Simons/Smith (Truth-makers [1984], §3)
Book Reference
'Truth and Truth-Making', ed/tr. Lowe,E.J./Rami,A. [Acumen 2009], p.70