But if science may be said to be blind without philosophy, it is true also that philosophy is virtually empty without science.

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

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.

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.

The traditional disputes of philosophers are, for the most part, as unwarranted as they are unfruitful.

The traditional disputes of philosophers are, for the most part, as unwarranted as they are unfruitful. The surest way to end them is to establish beyond question what should be the purpose and method of a philosophical enquiry. And this is by no means so difficult a task as the history of philosophy would lead one to suppose. For if there are any questions which science leaves it to philosophy to answer, a straightforward process of elimination must lead to their discovery.