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.

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.

No moral system can rest solely on authority.

It appears, then, that ethics, as a branch of knowledge, is nothing more than a department of psychologyand sociology.

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

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.

To make our position clearer, we may formulate it in another way. Let us call a proposition which records an actual or possible observation an experiential proposition. Then we may say that it is the mark of a genuine factual proposition, not that it should be equivalent to an experiential proposition, or any finite number of experiential propositions, but simply that some experiential propositions can be deduced from it in conjunction with certain other premises without being deducible from those other premises alone.