made inherent in it, but impulse or force impressed upon it _ab extra_;" and that "the cause of its motion must be sought for in something not matter, in some _immaterial cause or being_."--"Gravity," for instance, "is not the action of matter upon matter, but the virtue or power of an immaterial cause or being, constantly impressed upon it." Nor has this doctrine been confined to such metaphysical reasoners as Andrew Baxter. Professor Playfair tells us, that when he was introduced to Dr. Horsley, the Bishop "expressed great respect for Lord Monboddo, for his learning and his acuteness, and (what was more surprising) for the soundness of his judgment. He talked very seriously of the notion of _mind being united to all the parts of matter and being the cause of motion_. So far as I could gather, Dr. Horsley supposes that _every atom of matter has a soul_, which is the cause of its motion, its gravitation, &c. What has made him adopt this strange unphilosophical notion I cannot tell, unless it be the fear that his study of natural philosophy should make him suspected of Atheism, or at least of Materialism. For it is certain that there is at present a prejudice among the English clergy that natural philosophy has a tendency to make men Atheists or Materialists. This absurd prejudice was first introduced, I think, by that illiberal, though learned, prelate, Dr. Warburton."[160] A similar opinion has been recently reproduced by Dr. Burnett in his "Philosophy of Spirits in relation to Matter," in which he attempts to show that the forces and laws of Nature cannot be proved to be _the result of anything inherent in matter alone_, and that they ought to be ascribed to some substantive and distinct, but immaterial and dependent _spirits_, called "the spirit of life," "the spirit of electricity," "the spirit of heat."[161].