 After laying out the arguments about what-is, the goddess turns to the route of mortals, in an account which she calls “deceptive.” Although Parmenides has been read as thus rejecting any possibility of cosmological inquiry (Barnes 1979, Owen 1960), there are forceful interpretations that allow for justified belief about the contingent world, a world that may or may not be, and is not such that it must be (Nehamas 2002, Curd 2004, Palmer 2009). The problem of mortals is that they mistake what they perceive for what there is (and must be). As long as one realizes that the world of perception is not genuinely real, and cannot therefore be the object of knowledge, it may be possible for there to be justified belief about the cosmos. Some details of Parmenides’ own cosmology are given, arguably as justified belief, in the Doxa section of the poem, and more in the testimonia from later authors. Parmenides seems to have been the first Presocratic to claim that the moon gets its light from from the sun and that the earth is spherical. Recently scholars have focused on these claims about the natural world, and have argued that Parmenides should be understood as offering an account of appearances that can and should be deemed acceptable (Palmer 2009, Cordero 2010, Graham 2013, Mourelatos 2013, Bryan 2012, Johansen 2016). Nevertheless, Parmenides marks a sharp distinction between being (what-is and must be) and becoming, and between knowledge and perception-based belief or opinion.