If, from a standpoint of somewhat mystical piety, some minds of the seventeenth century regarded the sciences as useless, a paradoxical stoicism accused them in the eighteenth to be a cause of corruption and decay in society. Such is J. J. Rousseau's celebrated thesis in his first speech at the Academy of Dijon. This celebrated paradox, which has created so much excitement in the past century, and which is even an historical event (for it was the first attack against the society of the time), has since been so decried that it is useless to dwell on it. Let us make a brief _résumé_ of J. J. Rousseau's arguments: 1. Progress in letters and sciences serves for nothing else but to conceal the vices and put hypocrisy in the place of an ill-bred rusticity. 2. All great nations ceased to be invincible as soon as the sciences penetrated among them. Egypt, after the conquest of Cambyses; Greece, after Pericles; Rome, after Augustus. If, on the contrary, we look for examples of healthy, honest, vigorous nations, we find them among the ancient Persians, Scythians, Spartans, the first Romans, the Swiss. 3. The sciences and arts are born of and nourish idleness. Their least mischief is uselessness.[116] 4. The letters and arts engender luxury, and luxury is one of the powerful instruments of corruption in morals: it destroys courage, lowers the character, and, by another consequence, depraves and corrupts the taste even. 5. Another consequence: the culture of the mind engenders sophisms, false systems, and dangerous doubts about religion and morality. These various arguments, taking them up one after the other, may be answered as follows: 1. It is nowise proved that in the age of ignorance vices were less numerous and less deeply rooted than in the more enlightened age. Decency is a good in itself, and is not always hypocrisy. Delicacy of mind robs at least vice of its grossest features; it diminishes and allays violence, which is a great source of crimes. 2. It is not true that military virtues (which, besides, are not the only admirable virtues) are destroyed by the culture of the mind: modern examples prove this sufficiently. 3. To say that the letters and sciences are born of and nourish idleness is an abuse of words. Wherein is the man who works mentally more idle than he who works with his hands? 4. The sciences and letters do not develop a taste for luxury: luxury would develop without them, and would be all the more frivolous and corrupting: they are concomitant, but not mutually related facts. Luxury, besides, is not absolutely bad in itself: the taste for elegance is a legitimate one. Is not nature herself adorned? 5. Science develops wrong opinions, false systems: so be it; but it also corrects them, and we should look at both sides of a thing and see its good parts as well as its bad. Otherwise it would be easy to prove that everything is wrong.