Deism—­whether in the semi-Christian form of Rousseau or the anti-Christian form of Voltaire—­was a house built on the sand, and thinkers arose in France, England, and Germany to shatter its foundations.  In France, it proved to be only a half-way inn to atheism.  In 1770, French readers were startled by the appearance of Baron D’Holbach’s System of Nature, in which God’s existence and the immortality of the soul were denied and the world declared to be matter spontaneously moving.

Holbach was a friend of Diderot, who had also come to reject deism.  All the leading

[159] ideas in the revolt against the Church had a place in Diderot’s great work, the Encyclopedia, in which a number of leading thinkers collaborated with him.  It was not merely a scientific book of reference.  It was representative of the whole movement of the enemies of faith.  It was intended to lead men from Christianity with its original sin to a new conception of the world as a place which can be made agreeable and in which the actual evils are due not to radical faults of human nature but to perverse institutions and perverse education.  To divert interest from the dogmas of religion to the improvement of society, to persuade the world that man’s felicity depends not on Revelation but on social transformation—­this was what Diderot and Rousseau in their different ways did so much to effect.  And their work influenced those who did not abandon orthodoxy; it affected the spirit of the Church itself.  Contrast the Catholic Church in France in the eighteenth and in the nineteenth century.  Without the work of Voltaire, Rousseau, Diderot, and their fellow-combatants, would it have been reformed?  “The Christian Churches” (I quote Lord Morley) “are assimilating as rapidly as their formulae will permit, the new light and the more generous moral ideas and the higher spirituality of

[160] teachers who have abandoned all churches and who are systematically denounced as enemies of the souls of men.”

In England the prevalent deistic thought did not lead to the same intellectual consequences as in France; yet Hume, the greatest English philosopher of the century, showed that the arguments commonly adduced for a personal God were untenable.  I may first speak of his discussion on miracles in his Essay on Miracles and in his philosophical Inquiry concerning Human Understanding (1748).  Hitherto the credibility of miracles had not been submitted to a general examination independent of theological assumptions.  Hume, pointing out that there must be a uniform experience against every miraculous event (otherwise it would not merit the name of miracle), and that it will require stronger testimony to establish a miracle than an event which is not contrary to experience, lays down the general maxim that “no testimony is sufficient to establish a miracle unless the testimony is of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish.”  But, as a matter of fact, no testimony exists of which the falsehood would be a prodigy.  We cannot find in history any miracle attested by a sufficient number of men of such unquestionable good