Editing Law of noncontradiction (section)

=== Heraclitus ===
According to both [[Plato]] and [[Aristotle]],<ref>{{citation|title=Metaphysics (IV,1005b)|last=Aristotle |quote=to suppose that the same thing is and is not, as some imagine that Heraclitus says}}</ref> [[Heraclitus]] was ''said'' to have denied the law of non-contradiction. This is quite likely<ref>{{citation|title=Fragments 36,57,59 (Bywater)|last=Heraclitus}}</ref> if, as Plato [[Law of Contradiction#Plato's synthesis|pointed out]], the law of non-contradiction does not hold for changing things in the world. If a philosophy of [[Becoming (philosophy)|Becoming]] is not possible without change, then (the potential of) what is to become must already exist in the present object. In "We step and do not step into the same rivers; we are and we are not", both Heraclitus's and Plato's object simultaneously must, in some sense, be both what it now is and have the potential (dynamic) of what it might become.<ref>{{citation| last=Cornford| first=F.M.| title=Plato's Theory of Knowledge|page=234}}</ref>

So little remains of Heraclitus' aphorisms that not much about his philosophy can be said with certainty. He seems to have held that strife of opposites is universal both within and without, therefore ''both'' opposite existents or qualities must simultaneously exist, although in some instances in different respects. "The ''road up and down are one and the same''" implies either the road leads both ways, or there can be no road at all. This is the logical [[Complement (set theory)|complement]] of the law of non-contradiction. According to Heraclitus, change, and the constant conflict of opposites is the universal [[logos]] of nature.