In other words, the propositions of philosophy are not factual, but linguistic in character - that is, they do not describe the behaviour of physical, or even mental, objects; they express definitions, or the formal consequences of definitions. Accordingly we may say that philosophy is a department of logic. For we will see that the characteristic mark of a purely logical enquiry, is that it is concerned with the formal consequences of our definitions and not with questions of empirical fact.
A.J. AyerIt is time, therefore, to abandon the superstition that natural science cannot be regarded as logically respectable until philosophers have solved the problem of induction. 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.
A.J. AyerTheism is so confused and the sentences in which "God" appears so incoherent and so incapable of verifiability or falsifiability that to speak of belief or unbelief, faith or unfaith, is logically impossible.
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 misfortunes which God is represented in the book of Job as allowing Satan to inflict on Job, merely to test his faith, are indications, if not of positive malevolence, at least of a suspicious and ruthless insecurity, which is characteristic more of a tyrant than of a wholly powerful and benevolent deity.
A.J. Ayer