[197] Preller, Hist. Philosoph. Græc.-Rom. ex Font. Loc. Contexta, sect. 68. Preller thinks that Diogenes employed his chief attention “in animantium naturâ ex aeris principio repetendâ”; and that he was less full “in cognitione τῶν μετεώρων”. But the fragments scarcely justify this.
Leukippus and Demokritus — Atomic theory.
Nearly contemporary with Anaxagoras and Empedokles, two other enquirers propounded a new physical theory very different from those already noticed — usually known under the name of the atomic theory. This Atomic theory, though originating with the Eleate Leukippus, obtained celebrity chiefly from his pupil Demokritus of Abdera, its expositor and improver. Demokritus (born seemingly in B.C. 460, and reported to have reached extreme old age) was nine years younger than Sokrates, thirty-three years older than Plato, and forty years younger than Anaxagoras.[198] The age of Leukippus is not known, but he can hardly have been much younger than Anaxagoras.
[198] Diogen. Laert. ix. 41. See the chronology of Demokritus discussed in Mullach, Frag. Dem. p. 12-25; and in Zeller, Phil. der Griech., vol. i. p. 576-681, 2nd edit. The statement of Apollodorus as to the date of his birth, appears more trustworthy than the earlier date assigned by Thrasyllus (B.C. 470). Demokritus declared himself to be forty years younger than Anaxagoras.
Long life, varied travels, and numerous compositions of Demokritus.
Of Leukippus we know nothing: of Demokritus, very little — yet enough to exhibit a life, like that of Anaxagoras, consecrated to philosophical investigation, and neglectful not merely of politics, but even of inherited patrimony.[199] His attention was chiefly turned towards the study of Nature, with conceptions less vague, and a more enlarged observation of facts, than any of his contemporaries had ever bestowed. He was enabled to boast that no one had surpassed him in extent of travelling over foreign lands, in intelligent research and converse with enlightened natives, or in following out the geometrical relations of lines.[200] He spent several years in visiting Egypt, Asia Minor, and Persia. His writings were numerous, and on many different subjects, including ethics, as well as physics, astronomy, and anthropology. None of them have been preserved. But we read, even from critics like Dionysius of Halikarnassus and Cicero, that they were composed in an impressive and semi-poetical style, not unworthy to be mentioned in analogy with Plato; while in range and diversity of subjects they are hardly inferior to Aristotle.[201]
[199] Dionys. ix. 36-39.
[200] Demokrit. Fragm. 6, p. 238, ed. Mullach. Compare ib. p. 41; Diogen. Laert. ix. 35; Strabo, xv. p. 703.
Pliny, Hist. Natur. “Democritus — vitam inter experimenta consumpsit,” &c.
[201] Cicero, Orat. c. 20; Dionys. De Comp. Verbor. c. 24; Sextus Empir. adv. Mathem. vii. 265. Δημόκριτος, ὁ τῇ Διὸς φώνῃ παρεικαζόμενος, &c.