432 PHILOSOPHY ciples a demonstration of the nature of the world, and the manner in which it is produced from simple substances. Natural theology considers questions pertaining to the existence and providence of God, and the moral order of the world. Psychology, although a modern term, first employed in a technical sense by Otto Casmann in 1594, dates from the time when the vovg of Anaxagoras invited the atten- tion of Socrates, who turned it from specula- tive to practical account. In the writings of the Old and the New Testament we have the germs of a psychology, traceable also in other monuments of ancient literature. In these, as well as in the sacred writings, the distinction of body, soul, and spirit (cvy/*a, tyvxfy, and irvevpa) is noted, the last term answering, as some con- tend, to the Aristotelian vovg, while Tpvxq is equivalent to " the vital and Phantastic soul," and aa/ia is vitalized matter. Plato, in several of his dialogues, discusses the nature and pow- ers of the soul. One of Aristotle's works was entitled He pi ^vxfa, and his view of its relation to cupa accords with his theory which makes God supreme over the universe. From his time psychology made little advance for many centuries. The nature and destiny of the soul, rather than its faculties, engaged the attention of the early Christian writers. With the scho- lastics, who often blindly followed Aristotle, psychology, as well as philosophy generally, was made subordinate to the interests of faith. In England, during the 17th century, the lead- ing writers on psychological questions were Sir John Davies, Bacon, Hobbes, and Locke. The last named had been preceded on the continent by Montaigne, Descartes, Pascal, Malebranche, Spinoza, and others of less note. From the time of Descartes, who posited as the starting point of philosophic certainty the argument, Cogito, ergo sum, and who emphasized the dis- tinction between mind and matter, two ten- dencies have been manifest in philosophy, which there have been repeated attempts to harmonize, the idealistic and materialistic, to which reference will hereafter be made. On- tology dates from the time of Aristotle. It has been defined by some as that part of phi- losophy which treats of what are now called categories, or radical notions of thought appli- cable to all objects. Aristotle was not only the first to posit absolute being as the proper subject matter of the "first philosophy," but to draw up a table of principles, empirically derived, which were termed categories, and in accordance with which all conceptions must be formed. Among his modern imitators are Kant, TVolf, and Hegel. The ontological argu- ment for the being of a God, hinted rather than drawn out by Augustine, is developed by Anselm, who holds that .the very notion of a good, a greater than which cannot be con- ceived, existing in the mind, implies an objec- tive reality. In this line of thought he is fol- lowed to some extent by Descartes, whose ar- .gument is substantially : Since I am finite, the idea of infinite substance could not be in me if this idea did not come from a really existing infinite substance. To this he added : I myself, who have the idea of God, could not exist without God ; and this idea is innate in me, in the same sense as the idea I have of myself. In later times the a priori argument for the being of a God has been elaborated by Dr. Samuel Clarke (1704), W. Gillespie (1854), and others. But it has been met by the objec- tion that it is not strictly a priori, since an- tecedent existence of some kind is the postu- late of the argument. Cosmology, investiga- ting the physical and moral order of the uni- verse, has produced a large amount of specu- lation, and made large contributions to litera- ture. At a very early period the relation of God to the world is shadowed forth in cos- mogonies and popular religious systems. Zo- roaster has been credited with an explana- tion (which may have been anterior to him) of the existence of evil in the world, which falls back on the theory of two superhuman principles, a good and an evil deity, for ever opposed. Something of a kindred nature is found in connection with Greek speculation, and is known as hylozoism. Matter is the im- practicable resistant principle, which cannot easily be moulded, and has in it the elements of imperfection and evil. Hence, as Plato said, " Eeason persuades necessity." Under a some- what modified form, the Persian doctrine was revived by Mani, and has been since known as Manichseism. It supplied an element of the Gnostic systems, and previous to his acceptance of Christianity was embraced by St. Augus- tine. During the middle ages it exerted a limited influence, but toward the close of the 17th century attention was called to it by the speculations of Peter Bayle. The favor with which he was disposed to regard it led Arch- bishop King to write his famous work on the " Origin of Evil." On this and kindred topics Leibnitz soon after presented his views, and his work bore the title of "Theodicy." In that line of discussion which he pursued, and in which he has been followed by numerous more recent writers, were involved nearly all the leading cosmological questions, including liberty and necessity. Natural theology, as a branch of philosophy, may be traced in Greek literature to the vovg of Anaxagoras. Socrates gave it a moral and religious significance. Aristotle's speculations were necessarily theis- tic, from his philosophical standpoint and his theory of causes. Moreover, it came to be widely felt that back of all motion there must be a mover, himself unmoved, and back of all proximate causes, dependent in their nature, there must be a first cause. Of this cause, to meet the demand of philosophy, unity must be predicated ; and to this fact may be attribu- ted that tendency to monotheistic speculation which betrays itself among some ancient wri- ters, even when surrounded by polytheistic in- fluences and institutions. This is manifest in
