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 UNIVERSE

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UNIVERSE

)p a prnprium, or logical accident. One may even nquiro into the genus, species, and specific difference )f a met apliysicnl accident (e.g. of cont inued quantity).

The above iiaragraplis might lie reviewed a.s oUows: According to their origin in a direct act of )erccption or in reflexion, univcrsals are divided into lirect and reflex universals. The direct universal, raiving, as it doe.s, the question of the reality of the )erceived being in nature, is metaphysical. In it ies only the possibility of being applied to many hings, but the relation of universality is not recog- lized in it. Consequently, it is also known as the 'material universal". The reflex universal includes he relation to individuals, and is thus known as the iniversale loyicum, or also as the "formal universal", ince it is recognized as universal. The universale lirectum is divided into the categories, since these epresent the various modes of existence in the actual )eing. Recognized by reflexion as the highest .species, he categories are included under the itniverKale logicum, i-hich isdivided into the five predicables: genus, species, pecific difference, proprium, and logical accident.

IV. Importance or the Problem of the Uni- ■ERS.'iLS. — Science in general, inasmuch as it is the
 * nowledge of the necessary and permanent drawn

rom the nature of things, is impossible without he recognition of the universals. Without such ecognition, it is degraded into the description of uccessive individual impressions. The war between he pure Darwinists and the physicists, who recognize latural .species which, in consequence of their mode if development and the influence of conditions, can >e arranged into various systematic species, has been Iready designated a new pha.se of the Scholastic ontroversy concerning universals. In physics and hemistry the constancy of the laws of nature depends m the constancy of the nature of things. In psychol- igy the existence of universals has led to the recogni- ion of the intellect as a faculty fundamentally distinct rom the senses. That metaphysics and logic would le an impossibility without univer.sals, is self-evident. Vithout universals ethics and a'sthetics would also le surrendered to a relativism ungoverned by- princi- iles, and thus to annihilation. Without universals mpre.ssionism in art and individual autonomy in life nust attain undisputed sway. To these tendencies orrespond in religion the exclusive validity of reli- if dogmas, and the complete displacement of dog- natic by historical mode of thought. A history of he controver.sj- concerning the universals and their elation to existence must neces.sarily be a presentation if the most fundamental differences of all philosophi- al sy.stems. It would reveal that a deviation from Iristotelean Thomistic moderate Realism leads, on he one side, over Conceptualism and Nominalism to icppticism and Agnosticism, or to barren Empiricism nd Materialism, and on the other side over extreme iealism to false Idealism and Pantheism.
 * ious experiences, the beUef in the changing content

John Rick.iby, General Melnphysics (London, 1909) ; Bren- 'ANO, Ion dcr mannigfachen Bedeiitung des Seienden jiach Aris- 7leles (Freiburg. 1862); Com.mer. Logik (Paderborn, 1897); Slohsnf.r, Modeme Philosophic (Frankfort, 1889); H.^tTR^AC, tisl. df la philosophie scholantiguc (Paris, 1872-80); Kleutgen, ^hilog. der Vorzeit (2nd ed.. Mvlni^ter, 1878) ; Liberatore. DclUi ononcfmainlHlfmtale (Rome, lS.';7-.59). tr. Derinq, Vniversalx; London. 1892); Werner, Thomas ron Aquino (Ratiahon, 1889); ViLLMANN, Gtach. des Idealismus (2nd ed.. Bruni-wick, 1907); VuLF, Hist, de la philos. m^diitale (2nd ed.. Louvain, 1905).

Alois Pichler.

Universe, Systems of thf,. — ITniverse for world) f here taken in the astronomical .sen.se, in its narrower r wi<ler meanings, from our terrestrial planet to he stellar universe. The term "systems" restricts the iew to the general structure and mot ions of the heav- nly bodies, but comprises all the ages of the world, he present, p.isf, and future.

I. Historic Times of the Univer.se. — The pres- nt system, in the widest sense of the term, forms the

subject of universal cosmography. Descriptions of this kind were m.ade by Lambert, the two Herschels, Laplace, Newcnmb, and others. The present section treats only of the solar system, and in jiarticular of the disputed theories of Ptolemy and Copernicus, and the proofs in favour of the latter.

A. Pinkmaic and Copcmican Systems. — (1) The earliest astronomical systems are foimd in the Greek school. No planetary system can be discerned in Chinese or Babylonian records. The astronomical knowledge of the Greeks shows three periods. Its in- fancy is represented by Philolaus and Eudoxus, of the fifth and fourth century B. c. The earth is the com- mon centre of the universe, within the celestial sphere of the fixed stars. The great luminaries, sun and moon, and the five planets have each their concentric spheres, upon which they slide in two directions, longi- tude and latitude, keeping constantly the .same dis- tance from the earth. The flourishing period of Greek astronomy extends from Heraclidcs Ponticus in the fo\irth century B. c. to Hipparchus in the second. Observation was made its basis. The different de- grees of brilliancy observed in the nearest planets, Mercury, Venus, and Mars, at the times of the oppo- sition and conjunction with the sun, pointed to helio- centric orbits, and analogy demanded the same ar- rangement for Jupiter and Saturn. The hypothesis was then established, probably by Heraclidcs himself, that the sun revolved annually, with the five planets, around the earth, while the moon remained on her sphere as before. Heraclidcs also made an important step in advance by asserting the diurnal rotation of the earth. His system was afterwards known as that of Tycho Brah6. Even the annual motion of the earth around the sun is mentioned by Herachdes as held by some of his contemporaries. The heliocentric system was certainly pronounced and defended by Ari.star- chus of Sainos, although his mitings are lost, and known only through Archimedes, wliose works were pubhshedayearafterCopernicus'sdeath (Basle, l.'i44).

The period of decline had commenced when Hip- p.archus flashed up as the last genius among the Greek astronomers. The precession of the equinoxes, which he discovered, was made to fit the geocentric system, then prevailing, only a century after Aris- tarchus. The iihilosophical schools, in particular the Stoics, began to prefer astrology to observational astronomy. The geometrical knowledge that ap- parent or relative motion remains unaflFected by an interchange of its component motions, .as was correctly demonstrated by Apollonius, paved the way to the confusion of the solar system. It must be remem- bered that the apparent planetary motions are epi- cyclical, each planet revolving in its own orbit, the epicycle, around the sun, and with the sun, as centre of tiie epicycle, apparently around the earth in a common orbit, which is called the deferent orbit. These are the correct ideas, and will ever form the basis of spherical astronomy.

The decadence of astronomical concejits .among the Greek philo.sophcrs appeared in two ways. First, they applied the geometrical fiction of .Aixillonius to the physical planetary system, supposing that the epicycle must always be the smaller of the two com- ponents in apparent motion; and, secondly, they be- lieved that a physical planet could revolve, all alone, around a fictitious point in space. For the outer planets. Mars, .Jupiter, and Saturn, the apparent orbit of the sun is the smaller component — the common deferent orbit. It cannot b(> made the ejiicycle, with- out introducing into the system three new circles each with a fictitious centre. This was done, but worse was to come for the inner planets, Venus and Mercury. There was no need for them to di.slodge the common deferent circle, or solar orbit, as it was larger than the two planetary epicycles. And yet the centre of the deferent was moved from the sun towards the earth,