This inference from the shells and prints of fishes is very remarkable for so early a period. Compare Herodotus (ii. 12) who notices the fact, and draws the same inference, as to Lower Egypt; also Plutarch, De Isid. et Osirid. c. 40, p. 367; and Strabo, i. p. 49-50, from whom we learn that the Lydian historian Xanthus had made the like observation, and also the like inference, for himself. Straton of Lampsakus, Eratosthenes, and Strabo himself, approved what Xanthus said.] [Footnote 57: Xenophanes Frag. p. 161 seq., ed. Karsten. Compare Lucretius, v. 458. "per rara foramina, terræ Partibus erumpens primus se sustulit æther Ignifer et multos secum levis abstulit ignis . . . . Sic igitur tum se levis ac diffusilis æther Corpore concreto circumdatus undique flexit: . . . . Hunc exordia sunt solis lunæque secuta."] [Side-note: Parmenides continues the doctrine of Xenophanes--Ens Parmenideum, self-existent, eternal, unchangeable, extended,--Non-Ens, an unmeaning phrase.] Parmenides, of Elea, followed up and gave celebrity to the Xenophanean hypothesis in a poem, of which the striking exordium is yet preserved. The two veins of thought, which Xenophanes had recognised and lamented his inability to reconcile, were proclaimed by Parmenides as a sort of inherent contradiction in the human mind--Reason or Cogitation declaring one way, Sense (together with the remembrances and comparisons of sense) suggesting a faith altogether opposite. Dropping that controversy with the popular religion which had been raised by Xenophanes, Parmenides spoke of many different Gods or Goddesses, and insisted on the universe as one, without regarding it as one God. He distinguished Truth from matter of Opinion.[58] Truth was knowable only by pure mental contemplation or cogitation, the object of which was Ens or Being, the Real or Absolute: here the Cogitans and the Cogitatum were identical, one and the same.[59] Parmenides conceived Ens not simply as existent, but as self-existent, without beginning or end,[60] as extended, continuous, indivisible, and unchangeable. The Ens Parmenideum comprised the two notions of Extension and Duration:[61] it was something Enduring and Extended; Extension including both space, and matter so far forth as filling space. Neither the contrary of Ens (Non-Ens), nor anything intermediate between Ens and Non-Ens, could be conceived, or named, or reasoned about. Ens comprehended all that was Real, without beginning or end, without parts or difference, without motion or change, perfect and uniform like a well-turned sphere.[62] [Footnote 58: Parmenid. Fr. v. 29.] [Footnote 59: Parm. Frag. v. 40, 52-56. [Greek: to\ ga\r au)to\ noei=n e)sti/n te kai\ ei)=nai. A)lla\ su\ tê=s d' a)ph' o(dou= dizê/sios ei)=rge no/êma, mêde/ s' e)/thos polu/peiron o(do\n kata\ tê/nde bia/sthô, nôma=|n a)/skopon o)/mma kai\ ê)chê/essan a)kouê\n kai\ glô=ssan; kri=nai de\ lo/gô| polu/dênin e)/legchon e)x e)me/then rhêthe/nta.]]