plexing. The natural confequence, mocritus, maintained the existence of therefore, of the difcuffion of points of a plenum in nature. Democritus afthis nature, was a diverfity of opinions ferted, that matter confifts of felf-exand a variety of fubtle and endlefs dif- iftent, eternal, incorruptible, and im putes. Yet this cannot with propriety penetrable atoms or indivifible particles, of which extenfion and figure are the be urged against Plato. effential properties. He likewife afCicero and Plutarch ferts a vacuum. both affirm that Epicurus derived his opinions from Democritus, and the former author charges Epicurus with a want of integrity and candour in concealing the obligation. During the time of the establishment of the Grecian fchool, under Thales and his fucceffors, the wife Samian Pythagoras became famous in Italy. This philofopher was one of the moft accomplished men of his time. He spent a confiderable time among the Egyptians, and travelled over many parts of the Eaft. There is great reafon to think that the knowledge of the true fyftem of the world, of which there are many proofs among his difciples, was obtained by him among the orientals. His opinions refpecting the phyfical caufes of things were fingular and mysterious. He fought for thefe caufes among the relations of number and the fymmetry of figures. The five regular folids were held by him to partake of fomething of a divine nature, and the harmony by which the spheres were fuppofed to be governed is among his inventions. His doctrine of the metempfychofis was probably one of the acquifitions he made in the east, where it is held even to this day. Heraclitus, Democritus, Pyrrho, and Epicurus, are the chief philofophers of the Italian school who have established fects. Very little is recorded of the first of thefe four, except that he was a mifanthrope. Democritus poffeffed a mind equal to the greatest undertakings, and his induftry was adequate to his extreme defire of acquiring knowledge. Skilled in the pursuits of men both from travel and his natural penetration, he regarded thofe purfuits as futile and beneath the notice of a philofopher. But this did not render him a mifanthrope like Heraclitus. A ftrong fenfe of the ridiculous accompanied his method of eftimating things. The occafions for exercifing this talent were not a few, and the habit of derifion increafed fo much that his countrymen are faid to have written to Hippocrates requesting his affiftance to cure the infanity of Democritus. Plato, and moft of the other philofophers before De The fame variety of opinions which divided the Grecian fchool after the death of Socrates, appeared likewife among the fucceffors of Democritus. The Pythagoreans, however, do not appear to have neglected the cultivation of that natural knowledge the firft principles of which were established by the founder of their fect; though the greater abilities of Pyrrho and Epicurus when compared with Theodorus and Ariftippus, followers of Socrates, enabled the former to fpread their opinions with greater fuccefs. From Pyrrho arofe the fceptics. The candour and hefitation of Democritus, who was more defirous of enquiring than dogmatizing, was imitated by Pyrrho, but with this difference, that he chofe to affirm nothing, and even to deny the existence or poffibility of certainty. He afferted that all things were indifferent, life or death, pleafure or pain, virtue or vice. And for thefe opinions, fo obviously productive of the greatest mischiefs to fociety, his country raised him to the honour of the priesthood, and exempted the ftudents of philofophy from taxes. Epicurus is reckoned of the Italian fchool, becaufe of the advantages he derived from Democritus, though he paffed the greatest part of his life at Athens. The opinions both of the ancients and moderns concerning this philofopher are various and contradictory. By fome he is reprefented as a man of fmall abilities, and debauch ed principles, while others defcribe him as the contrary character, and affirm that his dogmas refpecting pleasure ought to be understood as relating to the true pleasure which accompanies virtue and temperance. Among the ancients, in the fame rank with those which are now known to be unworthy of notice. Thus Plutarch de placitis philofophorum, lib. 3. cap. 13. gives an obfcure account of the opinions of Philolaus, Heraclides, and Ecphantus, from which it is probable that thofe philofophers were acquainted with the true fyftem of the world. Copernicus, in his preface to his celebrated work De Revolutionibus orbium cæleftium, quotes the paffage and another of the like nature from Cicero; but it seems rather ftrange that he should have overlooked another paffage in Plutarch's imperfect treatife De facie in orbe Lunae, in which the theory of gravity is very clearly expreffed. As the paffage is curious, a tranflation may be acceptable: "But the moon is prevented from falling by the violence of the motion by which the revolves, upon the fame principle that ftones or other weights are kept from dropping out of a fling by the fwiftnefs of their motion while they are whirled about. For every body will be carried according to its natural motion if not prevented by fome intervening caufe. The moon, therefore, does not move according to the action of her weight because her tendency is overcome by the violence of the circular motion." Thales of Miletus is regarded as the founder of the Ionic fchool of philofophers. Most of the opinions which are recorded of this great man are fuch as do him great credit. By travelling into Crete, Phenicia, and laftly Egypt, which was then the refidence of the best geometers, he acquired all the knowledge which thofe times poffeffed, and is faid to have made very confiderable difcoveries. He is affirmed to be the first who gave any rational account of the caufe of eclipfes, and even proceed ed fo far as to foretell them. The fucceffors of Thales attended chiefly to the study of nature till the time of So crates. Socrates, according to Cicero, was the first who called the attention of philofophers from the heavens, and fixed it upon the ftudy of morality. An intimate acquaintance with the fciences of the age he lived in, fhewed this ex cellent man how little they contributed to the advantage of mankind when compared with the knowledge and practice of thofe duties which become the man and the citizen. Without entirely ne glecting them, he exerted his endeavours to make his scholars more wor thy of efteem than admiration. It is a blot both on his character and that of his contemporaries, that he found it neceffary to have recourse to artifice, in order to procure that refpect and atten tion which his upright life and easy converfation deserved. It was not enough that Socrates was the first of moral philofophers, but fupernatural communications were pretended to. He affirmed he had a demon, or familiar fpirit, that directed him to good, and taught him to avoid evil. While philofophy was chiefly converfant among natural things the minds of men appear to have been calm, and the common ftudy of nature seemed ra ther to unite than divide them. But the ftudy of morality foon created di vifions. We can much more readily al low the fuperiority in learning than in morality. An acknowledged pre-emi nence in virtue either creates a laudable emulation, or the most rancorous envy. The example and precepts of the divine Socrates produced both thefe effects. Many of his fellow-citizens became more virtuous, but those who beheld him without amendment faw with anxi ety that his conduct was a continual reproach to their own. They became his enemies, and as the offender is always more implacable than the injured perfon, their hatred was not fatiated but with his life. He was accufed of fubverting the religion of his country, and condemned to drink poifon. Immediately upon the death of So crates, the Grecian fchool became divided into parties. It has been a difficulty in all ages to determine the origin of moral obligation, and the world is not yet agreed upon the fubject. Indeed the queftion itself has fo many complicated relations, and a confiderable know! fical habitudes, be wondered, and modern fuch plesing. The natale, mocritus, maintai Cerefore, of the fiction this nature, was zuivery and a vanery of notte potes. Tet this cannot be urged against ame as a plenum in natu as feed, that matter vani 3. er het, eternal, incont repele atoms or ind During the time he famines of the Grecian Local. meer and his fucceffor. teac thagoras became 12 12. philofopher was ne placed men at ccaniderable T and travelen Eat. There a that the know of the world, proofs amongs ained by hum opinions refrem of things wer which Heraci Te Epicure the Irafian fefta V frt of dee wick extenfion and hes se ax dana properties. He like ieru a vacuum. Cicero and Pa ar af dat Epicurus derive onam from Democritus, and same author charges Epicurus with a win of meerity and candour in com eLipe tie ongation, mety of opinions which d n an he ni It of 1 is ing ugh e of bli re who ftrict I an fchool after the appeared likewise vhich retion of Democritus, quirer eafily bowever, do not hich a get the cultivation mind. L C ore cre engaged s not re referring wilfully e the fucived and umber to y, till at hade our h is equal y effects, creation hor himderation s favour, de magder how netifm, he uni ✓ prin1 think ed ca 11 yet could many d mu were it is › the ad ad ancients, Cicero and Plutarch may be reckoned as fupporting the former opinion; and Lucretius, Seneca, and St. Jerome are among his panegyrifts. From the first of the two former writers it is put out of doubt that Fpicurus himself meant the pleasures of fenfe when he said that the fovereign good confifts in pleasure, though it must be allowed that the moderation, the vir tue, and the fortitude he difplayed in his life, fufficiently evince that it was not his intention that thofe pleasures fhould be carried to intemperance, however his difciples may have conducted themfelves. With regard to his abilities, and the reproach of his incultus fermo, the letters of his, preferved in Diogenes Laertius, if genuine, feem to do honour to his understanding, and, as far as can be judged at this distance of time, are written in a good attic ftyle. The philofophical opinions of Epicurus were, as has already been faid, nearly_the_fame as thofe of Democritus. To the properties of matter, extenfion, and figure, he added that of gravity. He allows the exiftence of infinite worlds in infinite space, all fubject to generation and corruption: an opinion productive of atheifm and of all others the most difficult to confute. The reader may fee this itated at large in Diderot's Effay on the Blind, or in the Characteristics of Shaftfbury. The opinion of the plurality of worlds was common to almoft all the Pythago reans. To return to the academies. The unfettled ftate of government at Athens, and the death of Socrates, induced Plato to retire to Megara with the elder Euclid. According to the cuftom of the age he vifited Egypt, and afterwards went into Magna Græcia to make himfelf acquainted with the Pythagorean philofophy, under Philolaüs, Archytas the Tarentine, and Eurytus. Upon his return, he fixed his refidence at a houfe and gardens, called the Academy, in the neighbourhood of Athens, from whence his followers have been called academics. Plato's moral philofophy confifted chiefly of that of Socrates, expreffed in the most elegant and animated ftyle. His natural philofophy was de rived from Heraclitus and Pythagoras, but new modelled by himself. Among other famous men who have done honour to the fchool of Plato, the great Ariftotle ftands in the first rank. After the death of his mafter, he retired into Lycia, and was afterwards entrusted by Philip of Macedon with the care of the education of Alexander the Great; but not caring to follow that prince in his wars, he retired to Athens, and taught philofophy in the Lyceum. The allowance of eight hundred talents from his pupil Alexander, to be applied to the procuring materials for an hiftory of animals, enabled this philofopher to make great advances in the ftudy of nature. fides his books of natural philofophy, he wrote many volumes on rhetoric, jurifprudence, politics, grammar, and other fubjects. His works lay hid for about one hundred and fixty years, by the care of Neleus, one of his fucceffors, who was fearful left they should be feifed by the king of Pergamus, who was at that time collecting a library. They were afterwards found and fold to an Athenian named Apellicon, from whom they were taken by Sylla and conveyed to Rome. Be Contemporary with Plato and Ariftotle, lived Diogenes the cynic, the fcholar of Antifthenes, who was a difciple of Socrates. The arrogance and pride of this fect of philofophers, their voluntary poverty, and their want of delicacy in reprimanding others is well known. It does not appear that the fcience of natural philofophy is much indebted to them. A few years after the death of Ariftotle the fect of ftoics was established at Athens by Zeno. Being much afflicted at a confiderable lofs he had fuftained in commerce, he happened to read one of the books of Xenophon, which affuaged his grief and gave him a degree of unexpected pleafure. He applied to Crates the cynic, and became his difciple. The indifference with which the cynics fuffered the want of what are generally called the neceffaries of life infpired him with the idea of the ftoic good man. Rejecting their effrontery and impudence, he 5. taught H taught the moft fevere morality, attended with the highest degree of fortitude and indifference for external accidents. Epictetus was of this fect. The few rational enquirers who were of no fect were difregarded among the many different orders of philofophers, and the fucceeding ages faw an impediment thrown in the way of free difquifition, which not only prevented its progrefs but even deftroyed the advancement already made. The Chriftian religion became established and was fupported by the civil power. It is a dreadful error for man to imagine himself entrusted with the authority of the Almighty, and the moft horrid of all cruelties which difgrace the annals of history are thofe which have been acted in the name of the Deity. The primitive fathers imagined it neceffary to philofophize in religious matters. They became Chriftian Platonifts, and diffeminated the feeds of an infinity of controverfies. Inftead of that mild and charitable forbearance which the example and precepts of Chrift invariably inculcated, the moft acrimonious difputes were agitated concerning what are called myfteries. Cabals, perfecutions, and a jealous obfervance of every thing which could be fuppofed in the moft diftant manner to affect the faith, contributed to fetter the minds of men. Science degenerated into a fuperficial and unmeaning play of words. Buried beneath vast aggregates of fyllogifms, confined to a few univerfal propofitions, which, being branched into numberlefs divifions, afforded a fpecies of empty knowledge calculated only to feed the vanity of its poffeffor, it feemed almost loft to the world. But the effect has ceafed pon the removal of the caufe. The reformation has been followed by a gradual increase of liberality and candour, and thence the fciences have derived infinite advantages. During the dark ages, when the fchoolmen flourished, the works of Ariftotle were regarded with a degree of reverence to which no book whatfoever can poffibly be entitled. For in their difputations a quotation from the works of that philofopher was allowed to rank with arguments drawn from reason and the nature of things. The well-known Defcartes may be faid to have put an end to the reign of the Stagyrite. The first book of his Principia is an admirable introduction to metaphyfics. It has its errors, but for itrength of thought and elegance of expreffion is perhaps unequalled. The following books difplay much ingenuity, though nothing but the very imperfect state of philofophy at the time of their publication can account for their being received and cultivated, Those who have not become inured to that strict and unbiaffed regard for truth, which is abfolutely neceffary for an enquirer into natural appearances, cannot eafily conceive the fafcinating effect which a received hypothefis has upon the mind. Nothing is lefs calculated for the human powers, and nothing is more defired than to account for every thing we fee. An interest is therefore created, and the paffions become engaged in favour of that fyftem which feems adequate to the talk, and does not require the laborious caution of referring to experiment. The eye is wilfully fhut upon the difficulties, while the fuccefsful elucidations are received and mutually contribute by their number to establish each others authority, till at length we can fcarcely perfuade ourfelves that the hypothefis which is equal to the explanation of fo many effects, can be nothing more than the creation of fancy. The illuftrious author himfelf, indeed, urges this confideration as a principal argument in his favour, "Sed qui advertent quam multa de magnete, &c. But those who confider how many things relating to magnetism, fire, and to the conflruction of the univerfe are here deduced from a few principles, even though they should think thofe principles have been affumed cafually and without reafon, will yet perhaps acknowledge that it could fcarcely have happened that fo many things should agree together, and mutually confirm each other, if they were falfe." Principia fub fine. And it is remarkable, that in his epiftle to the French tranflator of this book, he advifes that the book ought to be "read |