  Second, there is the influence of Eleatic arguments, due to Parmenides, concerning the metaphysical requirements for a basic explanatory entity within this Milesian framework, and the metaphysically proper way to go about inquiry (Curd, 2004, 2007; Sisko 2003; for different views, see Palmer 2009, Sisko 2013).  Parmenides can be seen as arguing that any acceptable cosmological account must be rational, i.e., in conformity with the canons for proper inquiry, and must begin with metaphysically acceptable entities that are wholly and completely what they are; are not subject to generation, destruction, or alteration; and are wholly knowable i.e., graspable by thought and understanding (Parmenides B2, B3, B7, B8; see Mourelatos 2008a). Anaxagoras bases his account of the natural world on three principles of metaphysics, all of which can be seen as grounded in these Eleatic requirements: No Becoming or Passing-Away, Everything is in Everything, and No Smallest or Largest.