PLATO'S DOCTRINE RESPECTING THE ROTATION OF THE EARTH, AND ARISTOTLE'S COMMENT UPON THAT DOCTRINE. BY GEORGE GROTE, ESQ. LONDON: JOHN MURRAY, ALBEMARLE STREET. 1860. _The right of Translation is reserved._ LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET, AND CHARING CROSS. EXAMINATION OF THE THREE FOLLOWING QUESTIONS:-- 1. WHETHER THE DOCTRINE OF THE EARTH'S ROTATION IS AFFIRMED OR IMPLIED IN THE PLATONIC TIMÆUS? 2. IF AFFIRMED OR IMPLIED, IN WHAT SENSE? 3. WHAT IS THE COSMICAL FUNCTION WHICH PLATO ASSIGNS TO THE EARTH IN THE TIMÆUS? PREFACE. The following paper was originally intended as an explanatory note on the Platonic Timæus, in the work which I am now preparing on Plato and Aristotle. Interpreting, differently from others, the much debated passage in which Plato describes the cosmical function of the Earth, I found it indispensable to give my reasons for this new view. But I soon discovered that those reasons could not be comprised within the limits of a note. Accordingly I here publish them in a separate Dissertation. The manner in which the Earth's rotation was conceived, illustrates the scientific character of the Platonic and Aristotelian age, as contrasted with the subsequent development and improvement of astronomy. PLATO--ON THE EARTH'S ROTATION. In Plato, Timæus, p. 40 B, we read the following words--[Greek: Gê=n de\ tropho\n me\n ê(mete/ran, ei(llome/nên de\ peri\ to\n dia\ panto\s po/lon tetame/non phu/laka kai\ dêmiourgo\n nukto/s te kai\ ê(me/ras e)mêchanê/sato, prô/tên kai\ presbuta/tên theô=n, o(/soi e)nto\s ou)ra/nou gego/nasi.] I give the text as it stands in Stallbaum's edition. The obscurity of this passage is amply attested by the numerous differences of opinion to which it has given rise, both in ancient and in modern times. Various contemporaries of Plato ([Greek: e)/nioi]--Aristot. De Coelo, II. 13, p. 293 b. 30) understood it as asserting or implying the rotatory movement of the earth in the centre of the Kosmos, and adhered to this doctrine as their own. Aristotle himself alludes to these contemporaries without naming them, and adopts their interpretation of the passage; but dissents from the doctrine, and proceeds to impugn it by arguments. Cicero mentions (Academic II. 39) that there were persons who believed Plato to have indicated the same doctrine obscurely, in his Timaeus: this passage must undoubtedly be meant. Plutarch devotes a critical chapter to the enquiry, what was Plato's real doctrine as to the cosmical function of the earth--its movement or rest (Quaestion. Platonic. VII. 3, p. 1006.)