Philosophy Series: The Presocratics

I’d to like to start what I’ll call a Philosophy Series of posts in which I write essays on the various parts and ideas within philosophy. I specialized in philosophy during my undergrad at the University of Toronto, and while I certainly wasn’t the best in my class (philosophy is really hard, guys), I never lost my love for this subject and all it encompasses and want to bring it back into my life in a more permanent way. I think my love of philosophy is also part of why I love science fiction, since the two commingle so easily.

So in this first post, I’ll go over some of the ideas from the Presocratics, those philosophers who came before Socrates back in the day. The Presocratics were interested in nature, the essence of things, religion, epistemology, metaphysics, and cosmology.

Thales, Anaximander, Anaximenes

These three guys were what’s called material monists, meaning they believed the essence of all things is one material element.

Thales believed all things are made of water. Anaximander believed all things are made of the boundless, or apeiron, and Anaximenes believed all things are made of air/aer. If a thing or element appears otherwise, it’s only because a surface level change has taken place. But really all things can be reduced to that one element.

Unfortunately, we only have various fragments left indicating what the Presocratics thought, and not even direct fragments but what philosophers after them reported. We have very few fragments regarding the beliefs of Thales, Anaximander, and Anaximenes it seems, other than those indicating the above beliefs.


Pythagoras, of Pythagorean Theory fame, comes next. Pythagoras was big on the idea of the transmigration of the soul, meaning reincarnation.

“First he declares that the soul is immortal; then that it changes into other kinds of animals; in addition that things that happen recur at certain intervals, and nothing is absolutely new; and that all things that come to be alive must be thought akin. Pythagoras seems to have been the first to introduce these opinions into Greece.” (Porphyry, Life of Pythagoras 19 = 14,8a) – Readings in Ancient Greek Philosophy, page 17.

Pythagoras was born around 570 BC so I find it fascinating that he developed this idea of reincarnation/transmigration of the soul. According to Wikipedia, he may have learned the idea from his teacher, Pherecydes, or brought the idea to Greece from India, which means he would have had to travel all the way there and back, though I’m not sure what evidence exists for that.

Another interesting idea from Pythagoras is that chaos can be brought into order through numbers. 


Xenophanes rejected the idea of the transmigration of the soul put forth by Pythagoras, but seems to have mainly been interested in epistemology, the theory of knowledge, and what we can know for sure, arguing that we must always be inquisitive and adopt inquiry to find out about the world. At the same time, he argued that we can’t really be sure about most things. This idea will be echoed by later philosophers, and I think it’s amazing that the Presocratics had adopted this healthy skepticism.

“No man has seen nor will anyone know the truth about the gods and all the things I speak of. For even if a person should in fact say what is absolutely the case, nevertheless he himself does not know, but belief is fashioned over all things [or, in the case of all persons]. (Sextus Empiricus, Against the Mathematicians 7.49.110 = 21B34) – Readings in Ancient Greek Philosophy, page 23.

Xenophanes also rejected the idea of polytheism/the idea of the Olympian gods, arguing instead that there is “a single, non-anthropomorphic god who is unmoving, but is all-seeing, all hearing, and all-thinking, and who ‘shakes all by the thought of his mind.'” This idea would seem to build on the monism of the earlier thinkers, that all things can be traced back to one essence.


Born about 540 BC, approximately 30 years after Xenophanes, Heraclitus argued that there are indeed things humans can know for sure, but we don’t think well enough to access that knowledge. He believed in the Logos (“thing said,” or “word”), a single divine law of the universe that rules and guides the cosmos (this part seems similar to Xenophanes). The Logos is an independent, objective truth that is available to all, seemingly through the link between it and the souls of human beings. However, most people don’t exercise their faculties in such a way as to gain this understanding.

“This logos holds always but humans always prove unable to understand it, both before hearing it and when they have first heard it…But other people fail to notice what they do when awake, just as they forget what they do while asleep.” (Sextus Empiricus, Against the Mathematicians, 7.132 = 22B1) – Readings in Ancient Greek Philosophy, page 25.


“But although the logos is common, most people live as if they had their own private understanding.” (Sextus Empiricus, Against the Mathematicians, 7.133 = 22B2) – Readings in Ancient Greek Philosophy, page 25.

Heraclitus is also the source of the common quote, “Much learning does not teach understanding.” Though the actual fragment reads, “Much learning (‘polymathy’) does not teach insight.” I find it fascinating that Heraclitus believed that there are divine things we can know through our souls and minds, but most of us choose to listen to the mob instead.

“Divine things for the most part escape recognition because of unbelief.” (Plutarch, Coriolanus 38 = Clement Miscellanies 5.88.4 = 22B86) Readings in Ancient Greek Philosophy, page 26.


“What understanding or intelligence have they? They put their trust in popular bards and take the mob for their teacher, unaware that most people are bad, and few are good.” (Proclus, Commentary on Plato’s Alcibiades I, p. 117, Westerink = 22B104) Readings in Ancient Greek Philosophy, page 26.

Heraclitus’ idea that we should exercise our faculties rightly and try to understand the divine Logos rather than trust the mob is particularly relevant today. It also speaks to the fact that Heraclitus must have recognized this as an issue during his day, otherwise he wouldn’t have commented on it. This brings us back to the Pythagorean idea that all things recur and nothing is absolutely new. I think Pythagoras is right on the money. We all know, both factually and instinctually, that history repeats itself, and that anxieties that we have today over certain issues aren’t new. Rather, we’ve been grappling with them for most of recorded history.

Perhaps this is simply part of the human condition, the never-ending quest to know what’s true, to think for ourselves, and to, with enough mental due diligence, escape the trap of the mental mob, relying instead on the Logos.


Parmenides seems to have agreed with Heraclitus that you must always assess arguments you are given, even if they seem certain, though he disagreed with Heraclitus’ metaphysics. He argued that you can’t trust your sense experience, but only what follows from what is/being. (This, however, also seems similar to Heraclitus, and incidentally, or perhaps not, Descartes, who famously rationalized about what could possibly be known about anything, concluding, “I think, therefore I am,” as a basic unit of knowledge and being.)

For Parmenides, genuine being is whole, unchanging, and one. “Only what has these features can be grasped by the understanding and genuinely known.” As such, Parmenides seems to reject the changing world as unreal. Any changes that we perceive, for example a seed turning into a tree, a caterpillar becoming a butterfly, or ourselves growing from childhood to adulthood, can’t actually be real and we can’t know them. He argues that what is can neither come to be nor pass away, nor change in any way because what is not is literally unthinkable.

But if our reality is unreal, what does exists then? What entity or thing can be said to have the features of genuine being? Our souls? God? This seems to remain unclear and the subject of various interpretations of what Parmenides means. Some scholars have argued that Parmenides really does mean that what is is a single, monistic entity, whereas others have interpreted him to mean that there can be many things that are, and each thing that is must be whole, one, and unchanging. For example, for X to be X it must be whole, unchanging, and one, and for Y to be Y it must be whole, unchanging, and one. Indeed, it seems even in antiquity Parmenides was interpreted both ways.

My question for Parmenides, though, would be is there anything underpinning our illusion of reality? Is what is/what can be grasped by the mind the foundation of our illusion? It seems there must be something underpinning reality if we can’t trust our senses because we do seem to exist in some way.

I’m not sure what the answer is here. There is an interpretation of Parmenides called the Modal Interpretation, that argues that Parmenides was a “generous monist,” meaning he believed that while there is only one true, whole, unchanging, necessary entity, there also exist other entities that are but are not necessary. The existence of what must be does not preclude the existence of what is but need not be. According to the Stanford Encyclopedia of Philosophy, “On this view, What Is imperceptibly interpenetrates or runs through all things while yet maintaining its own identity distinct from theirs.” In other words, what is is “coterminous but not consubstantial” with the cosmos/what we perceive. This would be seem to negate the idea that what is is the foundation of what we perceive, since the two would exist in the same space but be of totally different substances or essences. So, for Parmenides, what actually is the nature of reality?

Parmenides was quite the controversial thinker and I’m sure I could go on, but I’ll stop this post here and finish with the Presocratics in a subsequent post.

Here’s a summary of ideas so far.

In Summary

We started with the material monists, who believed that the nature of all things must be one element that can change its form. This seems consistent with Pythagoras’ later idea of the transmigration of the soul. The soul remains a consistent immortal entity though it changes its host.

Xenophanes also seems to believe in monism, though he rejected the idea of the transmigration of the soul. He argued against a pantheon of gods and for a single, non-anthropomorphic divine entity, further arguing that there are many things that we can’t actually know for sure.

Heraclitus said no, there are things we can know for sure, but we don’t usually engage our minds enough to be able to know them. He seems to have agreed with the idea that there is a single divine entity/law of the universe, calling it the Logos. Also, don’t cave to the mob.

Finally, we arrive at Parmenides, who agreed with Heraclitus that we must always think things through. He took metaphysics to the next level, arguing that genuine being must be whole, one, and unchanging, and everything that we perceive is fake news, since we perceive things as separate, plural, and changing. It’s unknown whether genuine being was a divine entity for Parmenides, building on Xenophanes and Heraclitus, or if he believed there was some foundation to our illusory existence, a real world behind the curtain, as it were, or if only our minds are real.

In my next post in this series, we’ll finish up with the Presocratics, before we get into Plato and Aristotle.


Cohen, Marc S., Patricia Curd, and C.D.C. Reeve, editors. Readings in Ancient Greek Philosophy: From Thales to Aristotle. Third ed. Indianapolis: Hackett Publishing Company, 2005.

Palmer, John, “Parmenides”, The Stanford Encyclopedia of Philosophy (Winter 2020 Edition), Edward N. Zalta (ed.), URL = <>.