Alfred Jules Ayer

"Condensed version of Language, Truth, and Logic"

"There never comes a point where a theory can be said to be true. The most that one can claim for any theory is that it has shared the successes of all its rivals and that it has passed at least one te…"

"The criterion which we use to test the genuineness of apparent statements of fact is the criterion of verifiability. We say that a sentence is factually significant to any given person, if, and only i…"

"Ayer entry in the Stanford Encyclopedia of Philosophy"

"I am using the word "perceive". I am using it here in such a way that to say of an object that it is perceived does not entail saying that it exists in any sense at all. And this is a perfectly correc…"

"The 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…"

"If now I…say "Stealing money is wrong," I produce a sentence which has no factual meaning — that is, expresses no proposition which can be either true or false. It is as if I had written "Stealing mon…"

"I exist" does not follow from "there is a thought now." The fact that a thought occurs at a given moment does not entail that any other thought has occurred at any other moment, still less that there …"