Since they make no explicit mention of either propositions or truth, a theory of truth-makers is neither a theory about propositions nor a theory about truth.
Knowing is not a matter of the subject's standing in a certain relation to a true proposition; indeed, their account makes no mention of beliefs, propositions, or truth.
Thus, while intuitive knowledge and derivative knowledge both involve knowledge of propositions (or truths), knowledge by acquaintance and knowledge by description both involve knowledge of things (or objects).
2. p. 689) Locke then defines reason as "the discovery of the certainty or probability of such propositions or truths, which the mind arrives at by deduction made from such ideas, as it has got by the use of its natural faculties; viz, by the use of sensation or reflection" (IV. XVIII.
Indeed, sentence types as such don't express propositions or possess truth conditions at all.
The view that facts make propositions or other truth-bearers true is one theory among many of truthmaking.
First, since his propositions are all either simple 1-place subject-predicate propositions or else truth-functional compounds of these, he apparently ignores relational predicates, the logic of relations, and the logic of multiple quantification.
(Stumpf, 1891, p. 503) Stumpf distinguishes the theory of knowledge as a field of study from that of psychology on the basis of the cardinal distinction between the domain of concepts and that of propositions or necessary truths, as put forth in his habilitation thesis.
In this work, following Wittgenstein and the members of the Vienna Circle, Ayer defended a verificationist theory of meaning (also called the verifiability principle), according to which an utterance is meaningful only if it expresses a proposition the truth or falsehood of which can be verified (at least in principle) through experience.
But we also have the firm intuition that the truth or falsity of a proposition depends upon the state of the world in a way in which the state of the world doesn't depend upon the proposition's truth or falsity.
