Alfred J Ayer - Collected Quotes

"But if science may be said to be blind without philosophy, it is true also that philosophy is virtually empty without science." (Alfred J Ayer, "Language, Truth and Logic", 1936)

"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 if, he knows how to verify the proposition which it purports to express - that is, if he knows what observations would lead him, under certain conditions, to accept the proposition as being true, or reject it as being false." (Alfred J Ayer, "Language, Truth and Logic", 1936)

"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 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." (Alfred J Ayer, "Language, Truth and Logic", 1936)

"The problem of induction is, roughly speaking, the problem of finding a way to prove that certain empirical generalizations which are derived from past experience will hold good also in the future. There are only two ways of approaching this problem on the assumption that it is a genuine problem, and it is easy to see that neither of them can lead to its solution." (Alfred J Ayer, "Language, Truth and Logic", 1936)

"There is no field of experience which cannot, in principle, be brought under some form of scientific law, and no type of speculative knowledge about the world which it is, in principle, beyond the power of science to give." (Alfred J Ayer, "Language, Truth and Logic", 1936)

"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 test which they have failed." (Alfred J Ayer, "Philosophy in the Twentieth Century", 1982)