It was Voltaire who gave to the literary movement that decisive tone of irreligion, which it so long retained. The Church stood in the van of the opponents whom the philosophers had to encounter, and to attack the Church, her practice and her creeds, was to Voltaire an intellectual delight. More than any other institution the Church in France represented the spirit of tradition, of authority, of submission to formulas, of reverence for the past. As such, she was certain to view with alarm the new spirit of independent enquiry. Of all forms of political power, the political power of the Church was the most unpopular. She stepped in to support with mysterious sanctions the civil institutions which many felt were unjust. As the censor of the Press, she represented the Government at the very point where the Government and the philosophers came into conflict. Of all the supports of the old order, she was in many ways the most open to attack. Consequently, the philosophic movement from the first brought its forces to bear upon the Church, and Voltaire led the onslaught with the irreverent vivacity of his nature, and the rich splendour of his information and literary resource. In the middle of the eighteenth century, however, the conduct of the philosophic movement passed to a large extent into younger hands. In 1751, the first volume of the celebrated Encyclopaedia concentrated public attention on a group of writers of no common range and understanding, all inspired with the new spirit, and combined to carry it into every field of economic, political, and social action. The Encyclopaedists numbered among them many distinguished men. On the roll of their contributors we find the names of Turgot, Rousseau, Buffon, Marmontel. D'Alembert, the accomplished mathematician, brought to the work his trained abilities, his admirable style, and the wisdom acquired by a student during a life spent in frugality and independence. But the greatest of the staff, the most original in genius, the most reckless in expression, and the most intense and imaginative in thought, was the brilliant, perverse, impetuous Diderot, with his extraordinary, magnetic conversation, his indomitable perseverance, his genuine consciousness of his own shortcomings, his ardent desire for the improvement of mankind. It is significant that nearly all the prominent members of the Enyclopaedic party had been brought up as pupils of the Jesuits, and unquestionably, as a party, they associated themselves with a pronounced attack upon the chief tenets of the Catholic Church. But it is difficult and not very profitable to attempt to assign definite names of obloquy to the varieties of disbelief within their ranks, and it is a grave mistake to regard that aspect of their writings as the most characteristic or important. What gave to the enterprise its force and success was the fact that it travelled far beyond the barren conflicts of theology,