Heraclitus points out that everything flows. I can’t step in the same river twice, because the river is changing and I’m changing. He concludes that everything is characterized by contradiction which he calls strife.
Aristotle criticized Heraclitus by arguing — if everything is strife how could assertion be possible? He concluded the world is made of fixed essence with properties. When we assert for example that Socrates is musical we are asserting that the predicate of being musical applies to the individual Socrates. Aristotle and Heraclitus come to blows on the Principle of Non-Contradiction. According to Aristotle you can never have something which is p and not p at the same time and in the same respect. According to Heraclitus this happens all the time. Was that action good? It was and it wasn’t. Is that man going around the squirrel who sits on a tree and turns to look at him each step he takes circumabulating the squirrel or isn’t he? Well, he is and he isn’t.
Reading Aristotle can make you feel like his point is unassailable. How can you even assert something if you are willing to assert the opposite? If Heraclitus says everything flows it seems like he must thereby assert that something doesn’t flow — viz that everything flows. If he admits that it’s both true and not true that everything flows then he’s not asserting anything.
I believe that this point although seductive is wrong. Aristotle begs the question though by assuming that most of our use of language takes the form of asserting things. However if Heraclitus is right we must use language in a different way. What’s the way?
Let’s say I say of a particular woman that she is a mother. The concept of mother is changing as history changes — years ago it meant a biological mother, now it includes mother’s by adoption and perhaps egg donation. The concept of mother is flowing. And the particular woman? She’s also flowing. Her body and mind are the summation of numerous processes on numerous levels from the sub-atomic to the cultural. Yet somehow my use of language enables me to get a grip, itself a flowing phenomenon, on the situation I am in with her. My use of language “she is a mother” has success even though it doesn’t assert anything in Aristotle’s sense. It alters the direction of the flow but doesn’t stop it. It helps things along without freezing them. Me, my language, and the situation get in synch with each other but nothing obeys the law of non-contradiction.
How do we decide between these two ancient Greek smart guys? They differ on language and they differ on what there is. What is the court of higher appeal?
Aristotle can’t explain how Heraclitean uses of language are possible. But Heraclitus can explain how Aristotle’s use of language is possible. How? Just because everything flows doesn’t mean everything flows at the same rate. Our concept of triangle stayed the same for thousands of years. During that period of time the language we used to talk about triangles, for example “triangles have three sides” functioned pretty much the way Aristotle says assertions work. We were able to assert a property of an unchanging essence. Of course now that non-Euclidean geometry has been discovered, even triangles seem more Heraclitean. “Is that figure drawn on a sphere a triangle?” Well it is and it isn’t.
Why can Heraclitus explain Aristotle while Aristotle can’t explain Heraclitus? Because everything flows but some things flow faster. The river obviously flows. The banks of the river flow too. But everything flows.