Page:Collected Works of Dugald Stewart Volume 1.djvu/35

This page has been proofread, but needs to be validated.
ON D'ALEMBERT'S ENCYCLOPEDICAL TREE.
17

right use of signs, in order to knowledge; being toto cœlo different, they seemed to me to be the three great provinces of the intellectual world, wholly separate and distinct one from another."[1]

From the manner in which Mr. Locke expresses himself in the above quotation, he appears evidently to have considered the division proposed in it as an original idea of his own; and yet the truth is, that it coincides exactly with what was generally adopted by the philosophers of ancient Greece. "The ancient Greek Philosophy," says Mr. Smith, "was divided into three great branches, Physics, or Natural Philosophy; Ethics, or Moral Philosophy; and Logic. This general division," he adds, "seems perfectly agreeable to the nature of things." Mr. Smith afterwards observes, in strict conformity to Locke's definitions, (of which, however, he seems to have had no recollection when he wrote this passage,) "That, as the human mind and the Deity, in whatever their essence may be supposed to consist, are parts of the great system of the universe, and parts, too, productive of the most important effects, whatever was taught in the ancient schools of Greece concerning their nature, made a part of the system of physics."[2]

Dr. Campbell, in his Philosophy of Rhetoric, has borrowed from the Grecian schools the same very extensive use of the words physics and physiology, which he employs as synonymous terms; comprehending under this title "not merely Natural History. Astronomy, Geography, Mechanics, Optics, Hydrostatics, Meteorology, Medicine, Chemistry, but also Natural Theology and Psychology, which," he observes, "have been, in his opinion, most unnaturally disjoined from Physiology by philosophers." "Spirit," he adds, "which here comprises only the Supreme Being and the human soul, is surely as much included under the notion of natural object as body is; and is knowable to the philosopher purely in the same way, by observation and experience."[3]

  1. See the concluding chapter of the Essay on the Human Understanding, entitled, "Of the Division of the Sciences."
  2. Wealth of Nations, Book V. chap. i.
  3. Philosophy of Rhetoric, Book I. chap. v. Part iii. § 1.