 A few fragments, including one known only via Latin translation, show that Parmenides also dealt with the physiology of reproduction (frs. 17–18) and with human thought (fr. 16). Fortunately, the sketchy picture of the cosmology furnished by the fragments is significantly improved by the testimonia. The impression given by the fragments of the range of subjects is confirmed by both Simplicius, who comments after quoting fr. 11 that Parmenides’ account of the genesis of things extended down to the parts of animals (Simp. in Cael. 559.26–7), and likewise by Plutarch’s judgment that Parmenides’ cosmology has so much to say about the earth, heaven, sun, moon, and stars, right down to the genesis of human beings, that it omits none of the major subjects typically treated by ancient natural philosophers (Plu. Col. 1114B-C). A particularly important testimonium in the doxographer Aëtius paraphrases, explicates, and supplements fr. 12 in ways that give us a better picture of the structure of Parmenides’ cosmos (Aët. 2.7.1 = 28A37a Diels-Kranz). Likewise, Theophrastus’ comments on fragment 16 at De Sensibus 1–4 appear to provide more information about Parmenides’ views on cognition. The ancient testimonia tend to confirm that Parmenides sought to explain an incredibly wide range of natural phenomena, including especially the origins and specific behaviors of both the heavenly bodies and the terrestrial population. One fundamental problem for developing a coherent view of Parmenides’ philosophical achievement has been how to understand the relation between the two major phases of the goddess’ revelation.