But the Pythagoreans also were exponents of a form of atomic theory, and it seems probable that Pythagoras, a native of the island of Samos, was the first Greek to advance the doctrine of the discontinuity of matter. At least, none of his disciples ever claimed to have been the originator of this doctrine, and Pythagoras was born some time between 580 and 570 B. C., while the Atomic School of Leucippus was not founded until some time after 500 B. C. Unfortunately, Pythagoras did not commit his doctrines to writing, though a few of the so-called “Golden Sentences” may have been written by him. Most of them, however, are probably no older than the fourth century of our era. Moreover, these throw no light on the subject under discussion. The first written exposition of the Pythagorean atomic theory was put forward by Philolaus, a native of Tarentum, South Italy. Only fragments of his work have survived, and of those ascribed to him some are undoubtedly spurious. But all of them are very old and contain valuable information concerning Pythagorean doctrines. Porphyry (233-304? A. D.), a Syrian Neo-Platonist, residing for some years in Alexandria, wrote a “Life of Pythagoras,” and a few years later another “Life” of this philosopher appeared, this time from the pen--or stylus--of another Syrian and Neo-Platonist, Iamblichus. But these works contain much that is wholly mythical concerning Pythagoras.[3] Our best sources of information are Plato (_Timaeus_), Aristotle (_Metaphysica and Physica_, _De Anima and De Caelo_), Diogenes Laertius (_De Vitis_) and Stobaeus (_Eclogarum physicarum et ethicarum_). From these authorities we learn that, according to the Pythagoreans, the cosmos was at a certain stage of its (cyclic) changes a compact, inert, spherical mass of lifeless matter, having no distinguishable parts. After a long period of quiescence the “void”--i. e., the limitless outer air--broke in upon the world, entering into “the heaven itself” as if it--the heaven--were breathing. The result of this cosmic inhalation was “a certain separation and definition of things that lie together” (Aristotle, _Physica_, iv, 6)--that is, a separation of the homogeneous mass into different “elements.” These fragments were eventually ground into an all but infinite number of infinitesimal particles, or “monads,” analogous to the “atoms” of Leucippus and Democritus.