help thinking, and in the place of which we may, by possibility at least, entertain the opposite thought. To define opinion almost in one word, I should say that opinions are thoughts which we can help thinking.
4. Philosophy is the converse of opinion: philosophy therefore consists essentially of thoughts which we cannot help thinking; I say essentially, for such is the imperfection of our faculties, the limited extent of our knowledge, and the waste condition of our reason, which, looking to mankind generally, is very far from having received the culture of which it is susceptible; such, I say, is the actual state of things that opinion enters to a greater or smaller extent into the composition of philosophy. But it is present there as the accident, not as the essence. Opinions, or thoughts which a man can help thinking, have no business in philosophy. They are there under protest and only by sufferance, only until their places can be occupied by something better: occupied, that is, by thoughts which we cannot help thinking; for just as I have defined opinions as thoughts which we can help thinking, so I now define philosophy as that which is made up of thoughts which we cannot help thinking, necessary thoughts in short, the ground elements of reason.
5. Philosophy, then, is the embodiment and exposition of necessary thought, of thoughts which a man
