the ardour of the disciple pressed objections home with a trenchancy that is very unlike the sage distillations of the master.  It was from Shaftesbury, however, that he borrowed common sense as a philosophic principle.  Shaftesbury had indirectly drawn it from Locke, and through Hutcheson it became the source and sponsor of the Scottish philosophy of that century.  This was a weapon exactly adapted for dealing with a theology that was discredited in the eyes of all cool observers by the hysterical extravagances of one set of religionists, and the factious pretensions of their rivals.  And no other weapon was at hand.  The historic or critical method of investigation was impossible, for the age did not possess the requisite learning.  The indirect attack from the side of physical science was equally impossible.  The bearing of Newton’s great discovery on the current conceptions of the Creator and the supposed system of the divine government, was not yet fully realised.  The other scientific ideas which have since made the old hypothesis less credible, were not at that time even conceived.

Diderot did indeed perceive even so early as this that the controversy was passing from the metaphysicians to the physicists.  Though he for the moment misinterpreted the ultimate direction of the effect of experimental discovery, he discerned its potency in the field of theological discussion.  “It is not from the hands of the metaphysician,” he said, “that atheism has received the weightiest strokes.  The sublime meditations of Malebranche and Descartes were less calculated to shake materialism than a single observation of Malpighi’s.  If this dangerous hypothesis is tottering in our days, it is to experimental physics that such a result is due.  It is only in the works of Newton, of Muschenbroek, of Hartzoeker, and of Nieuwentit, that people have found satisfactory proofs of the existence of a being of sovereign intelligence.  Thanks to the works of these great men, the world is no longer a god; it is a machine with its cords, its pulleys, its springs, its weights."[32] In other words, Diderot had as yet not made his way beyond the halting-place which has been the favourite goal of English physicists from Newton down to Faraday.[33] Consistent materialism had not yet established itself in his mind.  Meanwhile he laid about him with his common sense, just as Voltaire did, though Diderot has more weightiness of manner.  If his use of the weapon cannot be regarded as a decisive settlement of the true issues, we have to remember that he himself became aware in a very short time of its inadequateness, and proceeded to the discussion, as we shall presently see, from another side.