Pre-Socratic Epistemology and Metaphysics: Parmenides and Heraclitus


The philosophers of ancient Greece sought to understand the rational structure of reality. 


I wish to take a brief look at the metaphysical systems of Heraclitus (535-475 BCE) and Parmenides (515-445 BCE). These men were similar in many regards. They were both “presocratic” philosophers who were primarily concerned with metaphysis (“the first philosophy”).  They both asked the very fundamental question: what exactly is the nature of reality/ being?  Both philosophers came to the conclusion that all the universe can be reduced to one basic substance: this is called “Monism”, which was first suggested by our good friend, Thales of Meletes.


However, while each was a monist, they had different ideas about what exactly this single substance was. Their disagreement on metaphysics would be extrapolated to include some very interesting implications.


The Philosophy of Heraclitus


Heraclitus believed that the universe was governed by a reason,  Reality was saturated, as it were, with reason, a sort of divine power guiding or directing “being.”  This he refers to as the “logos” which can be translated as word, law, principle, or meaning. 


"Of the Logos which is as I describe it men always prove to be uncomprehending, both before they have heard it and when once they have heard it. For although all things happen according to this Logos men are like people of no experience, even when they experience such words and deeds as I explain, when I distinguish each thing according to its constitution and declare how it is; but the rest of men fail to notice what they do after they wake up just as they forget what they do when asleep."


-- Sextus Empiricus, Against the Mathematicians (7.132)


This fundamental law of the universe held all things in perfect balance.  According to Heraclitus, the unity of the universe is composed of a balancing of opposites.  Day becomes night and hot will become cold. The continuous changing of reality was the one fundamental constancy within the cosmos. This belief lead Heraclitus to the conclusion that all things are always in flux and that the only thing that did not change was change itself.


There Needs to Be Tensions between Opposites -- 'strife'


1. 'It is necessary to know that war is common and justice is strife and that all things happen in accordance with strife and necessity.'


-- Origen, Against Celsus (6.42)


2. 'War is the father of all and king of all, and some he shows as gods, others as humans; some he makes slaves, others free.'


-- Hippolytus, Refutation (9.9.4)


For Heraclitus, the fundamental nature of “being” is was constant change between opposites. Life is followed by death, hunger to satiety to hunger again.  This strife or “war” within the nature of reality encompasses all things. All things are vibrating between opposite states; thus the universe is in an ironically “constant” state of flux.


Most famously he uses the example of a river. The philosopher stated that…


'Upon those who step into the same rivers, different and again different waters flow.'


--  Arius Didymus (Fr. 39.2)   [ most likely original ]


'[It is not possible to step twice into the same river] ... It scatters and again comes together, and approaches and recedes.'


--  Plutarch, On the E at Delphi (392b)


"We step into and we do not step into the same rivers. We are and we are not."


--  Heraclitus, Homeric Questions 24 Oelmann (Schleiermacher, fr. 72))


By this he means that the moment you step into a river, the water is displaced with new water and the nature of the river is changed permanently. But it is the same for the person doing the stepping.  Each of us are like the river in this respect, gaining and losing the “stuff” of our boies.   Unavoidable changes mean were never the “same” as we were.


Heraclitus took the stance that the universe was commanded by a divine reason or logos. The idea that the universe was always in a war of change and flux was the central tenant to this reasoning. Heraclitus believed that fire was the incarnation of a divine will that caused all change within reality and that the one undeniable law of the universe was that everything was always transforming into something else.


The Philosophy of Parmenides


Largely through a priori deductive reasoning, Parmenides concluded that actual change is impossible.[1]  His idea here is that something that exists (It is.) cannot also not exist (It is not.). (i.e. p & ~p is a logical contradiction)  Something cannot be and not-be.  Parmenides argues that a state of nothingness, a genuine “void” in reality could not be. Further, what is could not come from what is not/ nothing.  Likewise what is cannot “go into a state” of non- existence. (i.e. again this would require p & ~p)  Therefore all that is/exists/ be must have always exist/ be. The unchanging permanent nature of reality means reality is in fact an indivisible unity.


And so for Parmenides, there is no change. The reality/universe is continuous, unchanging and eternal. Now note that this is NOT the testimony of our senses.  Our senses (strongly) suggest that things are changing all the time, precisely as Heraclitus claims.  Parmenides ‘s radical metaphysics (along with the epistemology it implied) lead other philosophers to try to refute Parmenides monism and timelessness, especially since change in everyday life seem so much more evident than oneness.   Parmenides’s student Zeno famously defended his teacher’s views with his ingenious paradoxes about the space, time and motion (a principal kind of change).'s_paradoxes_part_i


While Parmenides took the stance that motion was impossible, is said that Heraclitus sought to disprove him. Heraclitus took his arm, moved it about his face and essentially said ‘there, I disproved it’. Parmenides then says that just because an arm is in one location one moment and then a different location the next, it does not necessarily mean that the arm actually moved.


To Parmenides, knowledge gained through the senses was unreliable.  Parmenides denounced the intuitions of sense experience as falsities, the way of “opinion” to be distinguished from actual knowledge. So the fact that we observe change/motion does des not demonstrate that change/motion are real.  The way of truth starts from an epistemological “ground zero,” then relies only on our reason and logic to arrive at a worthy conclusion. Thus despite appearances to the contrary, all “being” is one, and the multiplicity of individual beings is a mere illusion.


Parmenides was a pioneer in his use of logic and logical (deductive) inference.  He is said to have seen this as therapeutic or ministry free human minds from illusion and bringing them to reality.  Logic wasn’t merely an abstract philosophical effort.  Indeed all of authentic philosophy he viewed in this light.


Pre-Socratic Epistemology and Metaphysics: Parmenides and Heraclitus: Epilogue


So we see an early divide between those who see the best way of coming to know reality is though a priori reasoning, logic and rational intuition and those who believe we must rely on the testimony of our sense to come to know reality.  However, it should be noted that both positions seemed committed to the notion that reality is intelligible and that (unaided) human reason is capable of come to at least a partial understanding of it.  The logos of reality is accessible to or perhaps identical with the human intellect.


Parmenides argument took on moral and bore political implications once adopted the Sophists and by Protagoras in particular.  Protagoras sought to justify epistemic and ethical relativism, which his students used to discredit evidence in court and defend immorality. 


In Plato's Sophist, the sophists are referred to a "contradictors," and the "teachers of contradiction."[2] The Sophists were practiced rhetoricians contradicting any general statements "about being and becoming."[3] Sophists applied contradiction to "all arts" and "each craftsman," telling them how to do their jobs.[4] In Plato's Meno, Socrates says that "for more than forty years all Greece failed to notice that Protagoras was corrupting his classes and sending his pupils away in a worse state than when he took charge of them."[5] Aristotle accuses Protagoras and his rhetorical craft of making the weaker argument the stronger.  This “is why human beings were justly disgusted at Protagoras's pronouncement. For it is false, and not a true but an apparent likelihood, and not present in any art other than rhetoric and debating."[6] Plato and Aristotle claimed that Parmenides was also guilty of misleading people through "apparent likelihoods"  and this was a basis for Protagoras' relativism.[7]


The idea is this.  If the world of sense-perceived objects is a realm of illusions, judgments about is must all be equally false, none better than any other.  According to Aristotle, "[Protagoras] said that a human being is the measure of all things, meaning nothing else than that what seems so to each person is solidly so."[8] Things may seem different to you and the seem to seem, but there is no way to judge who is right. Indeed, we’re both equally wrong/right.  This position brings all evidence into question, allowing Protagoras to "make the weakener argument the stronger." The very concept of an enduring or universal human nature is called into question: "It is necessary for them [the Protagoreans] to say that all things are incidental, and that there is not anything which is the very thing it is to be human or to be an animal."[9] However, this is sheer lunacy for Aristotle.  "the same thing would be a battleship and a wall and a human being, if something admits of being affirmed or denied of everything, as it must for those who repeat the saying of Protagoras."[10]


Aristotle suggests Protagoras’s manages to be convinces by trading on two things: conflating matter of pure taste with matters of objective truth and utilizing the conclusions of Parmenides.  Dealing with Protagoras’s relativism requires dealing with both of these, as Plato too, attempted to so.



[1] Parmenides' line of argument is as follows. Change is coming into being. If something comes into being, it comes into being from something that existed before. What was it before? There are only two possibilities, which make up the Parmenides problem:

either : 1. Being comes from being.

or: 2. Being comes from nonbeing.

If #1 is correct and being comes from being, in that case the same thing exists before and after, and no change occurs. If #2 is correct and being comes from nonbeing, in that case nothing comes to be. Nothing comes from nothing after all, so no change occurs. The conclusion is that there is no such thing as nonbeing, and no such thing as change. The world is all one being, and there is no division into separate individual beings that interact and change.

[2] Plato, Sophist, trans. Seth Bernadette (Chicago: University of Chicago Press, 1986),, 232b

[3] Sophist, 232c.

[4] Sophist, 232e. The Eleatic Stranger mentions the "Protagorean writings on wrestling" specifically in this regard.

[5] Plato, Meno, trans. W.R.M. Lamb (Cambridge, MA: Harvard University Press, 1952), 91e. 

[6] Aristotle, Rhetoric, in Plato's Gorgias and Aristotle's Rhetoric, trans. Joe Sachs (Newburyport, MA: Focus Publishing, 2009), 1402a20.

[7] At Physics 186al, Aristotle says that "Melissus and Parmenides reason like debaters."

[8]  Metaphysics, 1062b 12

[9] Metaphysics, 1007a22. 

[10] Metaphysics, 1007b20.