admit in one part the weakness of our rational insight). Thus it is the duty of the philosopher (supposing even that he counts as nothing the claims of sincerity) to expose the above illusion, however wholesome it is, which such a confusion can produce; and to distinguish what merely belongs to persuasion from that which leads to conviction (for these are determinations of assent which differ not merely in degree but in kind), in order to present plainly the state of the mind in this proof in its whole clearness, and to be able to subject it frankly to the closest examination.

But a proof which is intended to convince, can again be of two kinds; either deciding what the object is in itself, or what it is for us (for men in general) according to our necessary rational principles of