Whatever moralists may hold, the human understanding is greatly indebted to the passions, which, it is universally allowed, are also much indebted to the understanding. It is by the activity of the passions that pur reason is improved; for we desire knowledge only because we wish to enjoy; and it is impossible to conceive any reason why a person who has neither fears nor desires should give himself the trouble of reasoning. The passions, again, originate in our wants, and their progress depends on that of our knowledge; for we cannot desire or fear anything, except from the idea we have of it, or from the simple impulse of nature. Now savage man, being destitute of every species of intelligence, can have no passions save those of the latter kind: his desires never go beyond his physical wants. The only goods he recognises in the universe are food, a female, and sleep: the only evils he fears are pain and hunger. I say pain, and not death: for no animal can know what it is to die; the knowledge of death and its terrors being one of the first acquisitions made by man in departing from an animal state.
How many ages may have elapsed before mankind were in a position to behold any other Are than that of the heavens
It would be easy, were it necessary, to support this opinion by facts, and to show that, in all the nations of the world, the progress of the understanding has been exactly proportionate to the wants which the peoples had received from nature, or been subjected to by circumstances, and in consequence to the passions that induced them to provide for those necessities.