 The kouros himself can reach a decision or determination of the truth solely through use of his logos. Logos here means thinking or reasoning (Parmenides probably means the human capacity for thought in general). The test (restated at B8.15–16/LMD8.20–21, is “is or is not?” This is not just a question of non-contradiction (which would give us coherence), but an inquiry whether or not the supposition that something is would entail, on further examination, the reality of what-is-not (which is impossible). 