If pressed to supplement Tweedledee's ostensive definition of logic with a discursive definition of the same subject, I would say that logic is the systematic study of the logical truths. Pressed further, I would say that a sentence is logically true if all sentences with its grammatical structure are true. Pressed further still, I would say to read this book.

Our talk of external things, our very notion of things, is just a conceptual apparatus that helps us to foresee and control the triggerings of our sensory receptors in the light of previous triggering of our sensory receptors.

One man's antinomy is another man's falsidical paradox, give or take a couple of thousand years.

Physics investigates the essential nature of the world, and biology describes a local bump. Psychology, human psychology, describes a bump on the bump.

Confusion of sign and object is original sin coeval with the word.

Some may find comfort in reflecting that the distinction between an eliminative and an explicative physicalism is unreal.

Theory may be deliberate, as in a chapter on chemistry, or it may be second nature, as in the immemorial doctrine of ordinary enduring middle-sized physical objects.