On the principles of natural things all the ancients have spoken with great ambiguity of language. They thought it was one of the primary objects of philosophy to ascertain the original substance, from which all things were composed ; and to this substance they gave the name of the first matter. Tholes chose water for the principle of his Cosmogony, and from him Pindar bor rowed the expression, AeITTOY 1.4,EY awe. Anaximenes and Diogenes, considering water as resolveable into air, maintained that this was the original principle of bodies. Hippasus and Heraclitus said fire ; Empedocles, water, air, fire, and earth. Pythagoras called in the agency of numbers and symmetry ; Musxus spoke of the one, Par rnenides of the infinite. Leucippus and Democritus re ferred to a plenum and vacuum ; Epicurus to atoms ; Anaxagoras to the Ofactottq>a, or similar particles, For the same purpose the doctrine of ideas was introduced by Plato. Aristotle, not satisfied with any of these sys tems, of which it is not easy to form a very definite notion, had recourse to matter, form, and privation ; the two former being the principles of generation, and the third the principle of corruption. He acknowledges that he derived some of his doctrines from the Pythago reans, and also often bestows great praise on the pene tration of Democritus, the great supporter of the atom ical philosophy. His opinions were, however, radically different from both, and by no means more satisfactory. Lord Bacon expresses his conviction, that the natural philosophy of Dcmocritus and others, who excluded mind altogether from the structure of things, was much more solid, so far as it relates to physical causes, than that either of Plato or Aristotle ; and for this sole rea son (he adds), because the former have never been mis led as the two latter have, by searching after final causes. On these different systems, a great profusion of learning has been amassed by Dr Cudworth, in his Intellectual System of the Universe.
The astronomical doctrines of Aristotle are of no value, but as a curiosity in the history of science. He proceeds on the supposition that the earth is immovea bly fixed at the centre of the system, round which the different spheres revolve. This most defective part of all his writings was adhered to with the greatest perti nacity during the middle ages, and was zealously de fended by the bigotry of scholastics after it was clearly demonstrated to be void of foundation.
In natural history it is scarcely possible to bestow suf ficient commendation on the diligence, fidelity, and ac curacy which he has evinced. His History of Animals, which the munificence of Alexander enabled him to complete at an enormous expense, contains a vast va riety of valuable observations, and has tended more than any other work to facilitate the labours of later zoolo gists. His knowledge of the human fabric indeed was very imperfect ; and his physiology abounds with errors.
Galen, one of the few who attempted to improve on Aristotle, while he allows him to have been not desti tute of skill in the art of dissection, speaks with great severity of his carelessness in referring the origin of the nerves to the heart, for no better reason than be cause, as he says, habet nervorum copiam cor ; on which Galen remarks, rather sarcastically, but not unjustly, that he might as well have said that they originate in the hand or the feet, as they are much more plentifully dispersed in these organs than in the heart. Aristo
tle did not understand the word nerve, as Galen gen erally does, in the modern acceptation ; but in that popular sense which was still prevalent in the days of Galen, denoting either nerve, properly so called, or liga ment, or tendon, which, according to this author, par takes of the nature of both. His anatomical knowledge had not led him to form any accurate conception of the functions of circulation, respiration, digestion, or secre tion. See ANATOMY.
The Metaphysics are so named, because, in arranging his works, the editors thought proper to place these abstract writings immediately after the Physics (cceTa Ta j) as it appeared that this was the order in which they might be most successfully studied. These works relate to being in general, to the reality and nature of truth, to the existence and attributes of the Deity, and to the inferior intelligent natures, particularly the hu man mind. We shall here observe, that in his specula tions concerning the supreme mind, there are many sublime and wonderful thoughts, blended, however, with occasional inconsistencies and perplexities. He not only describes the Deity as the eternal most excellent living being *oy Z‘ia`ov but as intelligence itself (Novc,) as incorporeal (G-0.q.c,,troc) as the original mover, himself immoveable (ro 9rearroy xtVotiY, cixtY4T0Y) as the principle of reason (€iex4 To you) as the cause and principle of all things, (c'irria xect ciexv Twy jYrtvv.) He also argues in this manner, ad absurdum, asserting the necessity of an in telligent cause. V.
Fen &Tat waga ciAAa, Ova icrar agxn aai 4E1 rims 'ex". " If there were nothing but material or sensible objects in the universe, there could be no original cause or order, but an eternal series of causes." Notwithstanding the de cided conviction which he so frequently expresses of the efficiency of this eternal mind, which he declares to be the cause of all order, and of the world itself, as well as the fountain of honour and rectitude„(Novv mai :tat 7ou xoT/hov 1.ar T115 7"aeCoc vracr5 rEITIOY-tliTIOY TOL xcaO15 MC4 zeaaiso it is difficult to understand what his notions could be, when he thought it necessary to conjoin nature with mind as the cause of the universe. CAvedvxm Youy nal OVTIY Tovh WaYT05. The vague and indefinite use of the term nature is a great source of the obscu rity of his theology. We cannot, however, hesitate to rank him among the theists, and we are also disposed to believe that whenever lie speaks the language of polytheism, it was in conformity with the idea that there were a number of spirits subordinate to the One su preme, but not a multiplicity of independent deities or first principles. Be indeed expressly asserts that the great Mind, who is pure and essential energy, is only one (iv thEY Kai Aoyeg xcet itv9fccu.) But we cannot acquiesce in the conclusion which he draws from this doctrine, that there can only be one world, or one hea ven. (aat To xiVoVfaiyoY ices cdEl ;cat OwyEZ0.15 iv ihoyoY if5 tea OVeay05 I.covoc.) Many of the other metaphysical doctrines, and par titularly those relating to human nature, are profound and interesting, though by no means uniformly valuable.