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. I might follow their progress into Greece, where they took root afresh, grew up and towered to the skies, among the rocks and sands of Attica, without being able to germinate on the fertile banks of the Eurotas: I might observe that in general, the people of the North are more industrious than those of the South, because they cannot get on so well without being so: as if nature wanted to equalise matters by giving their understandings the fertility she had refused to their soil.
But who does not see, without recurring to the uncertain testimony of history, that everything seems to remove from savage man both the temptation and the means of changing his condition? His imagination paints no pictures; his heart makes no demands on him. His few wants are so readily supplied, and he is so far from having the knowledge which is needful to make him want more, that he can have neither foresight nor curiosity. The face of nature becomes indifferent to him as it grows familiar. He sees in it always the same order, the same successions: he has not understanding enough to wonder at the greatest miracles; nor is it in his mind that we can expect to find that philosophy man needs, if he is to know how to notice for once what he sees every day. His soul, which nothing disturbs, is wholly wrapped up in the feeling of its present existence, without any idea of the future, however near at hand; while his projects, as limited as his views, hardly extend to the close of day. Such, even at present, is the extent of the native Caribean’s foresight: he will improvidently sell you his cotton-bed in the morning, and come crying in the evening to buy it again, not having foreseen he would want it again the next night.
In a word, how could such a situation induce men to cultivate the earth, till it was regularly parcelled out among them; that is to say, till the state of nature had been abolished?
The more we reflect on this subject, the greater appears the distance between pure sensation and the most simple knowledge: it is impossible indeed to conceive how a man, by his own powers alone, without the aid of communication and the spur of necessity, could have bridged so great a gap. What a multiplicity of chances must have happened to teach them the commonest uses of that element! How often must they have let it out before they acquired the art of reproducing it? and how often may not such a secret have died with him who had discovered it? What shall we say of agriculture, an art which requires so much labour and foresight, which is so dependent on others that it is plain it could only be practised in a society which had at least begun, and which does not serve so much to draw the means of subsistence from the earth -for these it would produce of itself-but to compel it to produce what is most to our taste? But let us suppose that men had so multiplied that the natural produce of the earth was no longer sufficient for their support; a supposition, by the way, which would prove such a life to be very advantageous for the human race; let us suppose that, without forges or workshops, the instruments of husbandry had dropped from the sky into the hands of savages; that they had overcome their natural aversion to continual labour; that they had learnt so much foresight for their needs; that they had divined how to cultivate the earth, to sow grain and plant trees; that they had discovered the arts of grinding corn, and of setting the grape to ferment-all being things that must have been taught them by the gods, since it is not to be conceived how they could discover them for themselves-yet after all this, what man among them would be so absurd as to take the trouble of cultivating a field, which might be stripped of its crop by the first comer, man or beast, that might take a liking to it; and how should each of them resolve to pass his life in wearisome labour, when, the more necessary to him the reward of his labour might be, the surer he would be of not getting it?