ignorant alike of human history and human nature, that only physical science can improve the social condition of man. The common sense of the world always rejects this gross fallacy. The acquiescence for so many centuries in the power of the great directing organisation of Western Europe, notwithstanding its intellectual inadequateness, was the decisive expression of that rejection.

After the middle of the last century the insurrection against the pretensions of the Church and against the doctrines of Christianity was marked in one of its most important phases by a new and most significant feature. In this phase it was animated at once by the scientific idea and by the social idea. It was an advance both in knowledge and in moral motive. It rested on a conception which was crude and imperfect enough, but which was still almost, like the great ecclesiastical conception itself, a conception of life as a whole. Morality, positive law, social order, economics, the nature and limits of human knowledge, the constitution of the physical universe, had one by one disengaged themselves from theological explanations. The final philosophical movement of the century in France, which was represented by Diderot, now tended to a new social synthesis resting on a purely positive basis. If this movement had only added to its other contents the historic idea, its destination would have been effectually reached. As it was, its leaders surveyed the entire field with as much accuracy and with as wide a range as their instruments allowed, and they scattered over the world a set of ideas which at once entered into energetic rivalry with the ancient scheme of authority. The great symbol of this new comprehensiveness in the insurrection was the Encyclopædia.

The Encyclopædia was virtually a protest against the old organisation, no less than against the old doctrine. Broadly stated, the great central moral of it all was this: that human nature is good, that the world is capable of being made a desirable abiding-place, and that the evil of the world is the fruit of bad education and bad institutions. This cheerful doctrine now strikes on the ear as a commonplace and a truism. A hundred years ago in France it was a wonderful gospel, and the beginning of a new dispensation. It was the great counter-principle to asceticism in life and morals, to formalism in art, to absolutism in the social ordering, to obscurantism in thought. Every social improvement since has been the outcome of that doctrine in one form or another. The conviction that the character and lot of man are indefinitely modifiable for good, was the indispensable antecedent to any general and energetic endeavour to modify the conditions that surround him. The omnipotence of early instruction, of laws, of the method of social order, over the infinitely plastic impulses of the human creature—this was the maxim which brought men of such widely different temperament and leanings to the common enterprise. Everybody can see what wide and deep-reaching bearings such a doctrine possessed; how it raised all the questions connected with psychology and the formation of character; how it went down to the very foundation of morals; into what fresh and unwelcome sunlight it brought the articles of the old theology; with what new importance it clothed all the relations of real knowledge and the practical arts; what intense interest it lent to every detail of economics and legislation and government.

The deadly chagrin with which churchmen saw the encyclopedic fabric rising was very natural. The teaching of the Church paints man as fallen and depraved. The new secular knowledge clashed at a thousand points, alike in letter and in spirit, with the old sacred lore. Even where it did not clash, its vitality of interest and attraction drove the older lore into neglected shade. To stir men's vivid curiosity and hope about the earth was to make their care much less absorbing about the kingdom of heaven. To awaken in them the spirit of social improvement was ruin to the most scandalous and crying social abuse then existing. The old spiritual power had lost its instinct, once so keen and effective, of wise direction. Instead of being the guide and corrector of the organs of the temporal power, it was the worst of their accomplices. The Encyclopædia was an informal, transitory, and provisional organisation of the new spiritual power. The school of which it was the great expounder achieved a supreme control over opinion by the only title to which control belongs: a more penetrating eye for social exigencies and for the means of satisfying them.

Our veteran humorist told us long ago in his whimsical way that the importance of the Acts of the French Philosophes recorded in whole acres of typography is fast exhausting itself, that the famed Encyclopædical Tree has borne no fruit, and that Diderot the great has contracted into Diderot the easily measurable. The humoristic method is a potent instrument for working such contractions and expansions at will. The greatest of men are measurable enough, if you choose to set up a standard that is half transcendental and half cynical. A saner and more patient criticism measures the conspicuous figures of the past differently. It seeks their relations to the great forward movements of the world, and asks to what quarter of the heavens their faces were set, whether towards the east where the new light dawns, or towards the west after the old light has sunk irrevocably down. Above all, a saner criticism bids us remember that pioneers in the progressive way are rare, their lives rude and sorely tried, and their services to mankind beyond price. "Diderot is Diderot," wrote one greater than Carlyle: "a peculiar individuality; whoever holds him or his doings cheaply is a Philistine, and the name of them is legion. Men know neither from God, nor from Nature, nor from their fellows, how to receive with gratitude what is valuable beyond appraisement" (Goethe). An intense Philistinism underlay the great spiritual reaction that followed the Revolution, and not even such of its apostles as Wordsworth and Carlyle wholly escaped the taint.

Forty years ago, when Carlyle wrote, it might really seem to a prejudiced observer as if the encyclopædic tree had borne no fruit. Even then, and even when the critic happened to be a devotee of the sterile transcendentalism then in vogue, one might have expected some recognition of the fact that the seed of all the great improvements bestowed on France by the Revolution, in spite of the woful evils which followed in its train, had been sown by the Encyclopædists. But now that the last vapours of the transcendental reaction are clearing away, we see that the movement initiated by the Encyclopædia is again in full progress. Materialistic solutions in the science of man, humanitarian ends in legislation, naturalism in art, active faith in the improvableness of institutions—all these are once more the marks of speculation and the guiding ideas of practical energy. The philosophical parenthesis is at an end. The interruption of eighty years counts for no more than the twinkling of an eye in the history of the transformation of the basis of thought. And the interruption has for the present come to a close. Europe again sees the old enemies face to face; the Church, and a Social Philosophy slowly labouring to build her foundations in positive science. It cannot be other than interesting to examine the aims, the instruments, and the degree of success of those who a century ago saw most comprehensively how profound and far-reaching a metamorphosis awaited the thought of the Western world. We shall do this most properly in connection with Diderot.

Whether we accept or question Comte's strong description of Diderot as the greatest genius of the eighteenth century, it is at least undeniable that he was the one member of the great party of illumination with a real title to the name of thinker.