DIO'GENES of Apollonia, so called from his birthplace, a town in Crete, was a pupil of Anaximenes and a contemporary of Anaxagoras. The years in which he was born and died are not known, as is the case also with his master Anaximenes. But the birth-year of his contemporary and fellow-pupil Anaxagoras is known to bo u.c. 500; and Diogenes would most probably be about the same age, or perhaps rather younger. Sidonius Apollinaris (xv. 91) speaks of Diogeues as younger than Anaxagoras. Schleiermacher, who is followed by richanbach, the editor of the fragments of Anaxagoras, affirms from the internal evidence of the fragments of the two philosophers, that Diogenes preceded Ana.xagoras. But Diogenes might have written before Ana:agoras, and yet have been his junior, as we know was the WO with Empedoeles. (Aristotle, 'Met,' p. 843 B.) Diogeues followed Auaximenea in making air the primal element of all thing% that out of which the whole material universe was formed; but he invested this air with the property of intelligence, or with whet is called by St. Augustin a divine virtue, thus approximating but not attaining to the system of Anaxagoras. It was reserved for this last philosopher to separato mind from matter. "As the con templation of animal life," says Thirlwall, "had led Anaximenes to adopt air as the basis of his system, a later philosopher, Diogenes of Apollonia, carried this analogy farther, and regarded the universe as issuing from an intelligent principle, by which it was at once vivified and ordered—a rational as well as sensitive soul—still without recog nising any distinction between matter and mind.". (' Hist. of Orecce,'
vol. ii., p. 134.) Cicero (' De Nat. Deor., L 12) represents Diogenes as making air his deity.
He wrote several books on Cosmology; and the first sentence of his work is given by Diogenes Leertius in two places (vi. 81 ; ix. 57). The fragments which remain have been recently collected and edited by Panzerbeiter.
There is an essay on the philosophy of Diogenes, by Schleiermacher, in the Memoirs of the Berlin Academy for 1815; and a contribution to the chronology of his life in an article on the early Ionic philoso phers, by Mr. Clinton, iu the 'Philological Museum,' vol. i., p. 92.
(For general information concerning him the reader is referred to Diogenes Lakrtius, ix.,9 ; Bayle, Dictionary; Fahricii, Bailie:Arca Ceara, ed. Harks, voL ii., p. 656.)