This can never become popular, and, indeed, has no occasion to be so; for fine-spun arguments in favour of useful truths make just as little impression on the public mind as the equally subtle objections brought against these truths. On the other hand, since both inevitably force themselves on every man who rises to the height of speculation, it becomes the manifest duty of the schools to enter upon a thorough investigation of the rights of speculative reason, and thus to prevent the scandal which metaphysical controversies are sure, sooner or later, to cause even to the masses.

A man who has tasted with profound enjoyment the pleasure of agreeable society will eat with a greater appetite than he who rode horseback for two hours. An amusing lecture is as useful for health as the exercise of the body.

In man (as the only rational creature on earth) those natural capacities which are directed to the use of his reason are to be fully developed only in the race, not in the individual.

If, like Hume, I had all manner of adornment in my power, I would still have reservations about using them. It is true that some readers will be scared off by dryness. But isn't it necessary to scare off some if in their case the matter would end up in bad hands?

There is something splendid about innocence; but what is bad about it, in turn, is that it cannot protect itself very well and is easily seduced.

Happiness, though an indefinite concept, is the goal of all rational beings

It is precisely in knowing its limits that philosophy consists.