The ground for taking ignorance to be restrictive of freedom is that i — A. J. Ayer

"There is philosophy, which is about conceptual analysis — about the meaning of what we say — and there is all of this … all of life."

"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 correct and familiar usage of the word. If there is thought to be a difficulty here, it is perhaps because there is also a correct and familiar usage of the word "perceive", in which to say of an object that it is perceived does carry the implication that it exists."

"No moral system can rest solely on authority."

"I see philosophy as a fairly abstract activity, as concerned mainly with the analysis of criticism and concepts, and of course most usefully of scientific concepts."

"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."

"(Martin Gardner) writes about various kinds of cranks with the conscious superiority of the scientist, and in most cases one can share his sense of the victory of reason. But after half a dozen chapters this non-stop superiority begins to irritate; you begin to wonder about the standards that make him so certain he is always right. He asserts that the scientist, unlike the crank, does his best to remain open-minded. So how can he be so sure that no sane person has ever seen a flying saucer, or used a dowsing rod to locate water? And that all the people he disagrees with are unbalanced fanatics? A colleague of the positivist philosopher A. J. Ayer once remarked wryly "I wish I was as certain of anything as he seems to be about everything". Martin Gardner produces the same feeling."