Discover what Heraclitus and Parmenides thought about change? Does change exist or is it just an illusion made by out senses?
The contrast between Heraclitus and Parmenides is about as stark as possible. Heraclitus accepts change as an unquestionable fact and uses inference to the best explanation based on an elemental interpretation of the world to develop his logos and the belief that fire or energy underlies all existence. On the other hand, Parmenides argues that ‘nothing’ is not a logical concept and is simply absurd, leading him to the conclusion that all of reality is a singular, uniform, unchanging, unmoving One that is limited in extent and spherical in nature. The contrast of change is not the only difference however, but also the contrast between the types of reasoning. Heraclitus founds his reasoning on a posteriori reasoning whereas Parmenides limits himself completely to a priori reasoning. Ultimately, Parmenides provides the stronger argument for his perception of existence.
Heraclitus’ first and most significant failure is accepting the notion that change is unquestionable. He does not bother to ask the nature of change, or the reasoning behind, but simply accepts it as a premise to his argument. Heraclitus puts his faith in his perception over reason when nearly anyone can tell you that senses can lie. For example, manner. My existence must be within Parmenides’ One then because if I existed outside I’d violate his conclusions. I experience change and flux, even if it’s a lie, I perceive change. Yet, how can something unchanging and permanent, even imagine change and flux? How can change, even in thought or perception exist in a static body?
Both Parmenides and Heraclitus suffer from weaknesses in their arguments. It falls down to too much of a dependence on a priori and a posteriori reasoning. Heraclitus does not address the validity of his assumptions because he believes them valid based solely on observation. On the other side of the coin Parmenides discounts any kind of experiential knowledge when his reasoning finds its basis in expectations from reality.