 The goddess does not provide the kouros with a list of true propositions, as a body of knowledge for him to acquire, and false ones to be avoided. Rather, in teaching him how to evaluate claims about what-is, the goddess unleashes the kouros’ own cognitive powers to know everything, by testing and evaluation, accepting or rejecting claims about the ultimate nature of things— for that alone is capable of being known. For Parmenides, the mark of what is known is that it is something that genuinely is, with no taint of what-is-not. That is why, for him, what-is not only is, but must be and cannot not-be. He sets this out in the key passages of DKB2 and  B3/LM19D6:[5]