_18th-Century Moralists and Politicians._--Not the least part, however, of the energy of the period in thought and writing was devoted to questions of a directly moral and political kind. With regard to morality proper the favourite doctrine of the century was what is commonly called the selfish theory, the only one indeed which was suitable to the sensationalism of Condillac and the materialism of Holbach. The pattern book of this doctrine was the _De l'esprit_ of Claude Adrien Helvetius (1715-1771), the most amusing book perhaps which ever pretended to the title of a solemn philosophical treatise. There is some analogy between the principles of this work and those of the _Systeme de la nature_. With the inconsistency--some would say with the questionable honesty--which distinguished the more famous members of the Philosophe party when their disciples spoke with what they considered imprudent outspokenness, Voltaire and even Diderot attacked Helvetius as the former afterwards attacked Holbach. But whatever may be the general value of _De l'esprit_, it is full of acuteness, though that acuteness is as desultory and disjointed as its style. As Helvetius may be taken as the representative author of the cynical school, so perhaps Alexandre Gerard Thomas (1732-1785) may be taken as representative of the votaries of noble sentiment to whom we have also alluded. The works of Thomas chiefly took the form of academic _eloges_ or formal panegyrics, and they have all the defects, both in manner and substance, which are associated with that style. Of yet a third school, corresponding in form to La Rochefoucauld and La Bruyere, and possessed of some of the antique vigour of preceding centuries, was Luc de Clapiers, marquis de Vauvenargues (1715-1747). This writer, who died very young, has produced maxims and reflections of considerable mental force and literary finish. From Voltaire downwards it has been usual to compare him with Pascal, from whom he is chiefly distinguished by a striking but somewhat empty stoicism. Between the moralists, of whom we have taken these three as examples, and the politicians may be placed Rousseau, who in his novels and miscellaneous works is of the first class, in his famous _Contrat social_ of the second. All his theories, whatever their originality and whatever their value, were made novel and influential by the force of their statement and the literary beauties of its form. Of direct and avowed political writings there were few during the century, and none of anything like the importance of the _Contrat social_, theoretical acceptance of the established French constitution being a point of necessity with all Frenchmen. Nevertheless it may be said that almost the whole of the voluminous writings of the Philosophes, even of those who, like Voltaire, were sincerely aristocratic and monarchic in predilection, were of more or less veiled political significance. There