We say that a sentence is factually significant to any given person, if, and only if, he knows how to verify the proposition which it purports to express.
A.J. AyerThe principles of logic and mathematics are true simply because we never allow them to be anything else. And the reason for this is that we cannot abandon them without contradicting ourselves, without sinning against the rules which govern the use of language, and so making our utterances self-stultifying. In other words, the truths of logic and mathematics are analytic propositions or tautologies.
A.J. AyerThe only possible basis for a sound morality is mutual tolerance and respect: tolerance of one anotherโs customs and opinions; respect for one anotherโs rights and feelings; awareness of one anotherโs needs.
A.J. AyerThe traditional disputes of philosophers are, for the most part, as unwarranted as they are unfruitful. The surest way to end them is to establish beyond question what should be the purpose and method of a philosophical enquiry. And this is by no means so difficult a task as the history of philosophy would lead one to suppose. For if there are any questions which science leaves it to philosophy to answer, a straightforward process of elimination must lead to their discovery.
A.J. Ayer