The point most emphasized in Toland's teaching [31] is that motion is an attribute of matter. He argues for this belief on the ground that matter must be essentially active in order to undergo change, [32] and that the conception of the inertness of matter is based on the conception of absolute rest, and that this absolute rest is nowhere to be found. [33] Since motion is essential to matter, there is no need, Toland believes, to account for the beginning of motion. Those who have regarded matter as inert have had to find some efficient cause for motion, and to do this, they have held that all nature is animated. But this pretended animation is utterly useless, since matter is itself endowed with motion. [34] The likeness to La Mettrie is evident. La Mettrie likewise opposes the doctrine of the animation of matter, and the belief in any external cause of motion. [35] Yet he feels the need of postulating some beginning of motion, [36] and although he uses the conception so freely, he does not agree with Toland that the nature of motion is known. He believes that it is impossible to know the nature of motion, [37] while Toland believes that the nature of motion is self-evident. [38] Another point of contrast between Toland and La Mettrie is in their doctrines of God. Toland believes that God, "a pure spirit or immaterial being," is necessary for his system, [39] while La Mettrie questions God's existence and insists that immateriality and spirituality are fine words that no one understands. It must be admitted, in truth, that La Mettrie and Toland have different interests and different points of view. Toland is concerned to discover the essential nature of matter, while La Mettrie's problem is to find the specific relation of body and mind. On this relation, he builds his whole system. b. The Relation of La Mettrie to an English Sensationalist: John Locke (1632-1704). Locke's "Essay Concerning Human Understanding" was published in 1690, and La Mettrie, like most cultured Frenchmen of the Enlightenment, was influenced by his teaching. The main agreement between Locke and La Mettrie is in their doctrine that all ideas are derived from sensation. Both vigorously oppose the belief in innate ideas, [40] teaching that even our most complex and our most abstract ideas are gained through sensation. But La Mettrie does not follow Locke in analyzing these ideas and in concluding that many sensible qualities of objects--such as colors, sounds, etc.--have no existence outside the mind. [41] He rejects Locke's doctrine of spiritual substances, [42] and opposes Locke's theistic teaching, laying stress, on the other hand, upon Locke's admission of the possibility that "thinking being may also be material." [43] IIIa. The Likeness, probable but unacknowledged, to La Mettrie, of the French Sensationalists, Etienne Bonnot de Condillac (1715-1780) and Claude Adrien Helvetius (1715-1771).