5 - Old Man River: Heraclitus

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Peter discusses the Pre-Socratic philosopher Heraclitus, and tries to discover whether it's possible to step into the same river twice.



Further Reading

R. Dilcher, Studies in Heraclitus (Hildesheim: Olms, 1995).

H. Granger, “Argumentation and Heraclitus’ Book,” Oxford Studies in Ancient Philosophy 26 (2006), 1-17.

C.H. Kahn, The Art and Thought of Heraclitus (Cambridge: Cambridge University Press, 1979).

M. Schofield, “Heraclitus’ Theory of Soul and its Antecedents,” in S. Everson (ed.), Psychology (Cambridge: Cambridge University Press, 1991), 13-34.

Stanford Encyclopedia: Heraclitus

History of Philosophy's Greatest Hits: Peter discusses Heraclitus on video


Anonymous on 24 February 2012

What is was, and was is.

Nothing changes. There is nothing which was, which already is. Listen not to me but the logos. What is right, and what is wrong. The logos is telling you the truth but you won’t hear it unless you are part of the stable change.

In reply to by Anonymous

Malcolm on 5 May 2012

Does modern physics agree with Heraclitus?

Is everything fire? Is everything unchanging *and* in continuous flux?

Fire is energetic matter. Matter is energy, and energy is matter, so everything is one (matter or energy or both).

Everything is changing. Matter-energy is in continuous flux. But nothing, fundamentally, is changing; it's still the same, unchanging, conserved matter-energy.

In reply to by Malcolm

Aaron Hald on 24 June 2012

know yourself first, if you would know the universe

"You talk about redefining my identity. I want a guarantee that I can still be myself."

"There isn't one. Why would you wish to? All things change in a dynamic environment. Your effort to remain what you are is what limits you."

In reply to by Aaron Hald

Somebody on 10 July 2012

Unless that quote was

Unless that quote was referred to in the episode (did not yet check, just arrived here), it would not have hurt to mention its source (Ghost in the Shell) while at it.

In reply to by Somebody

Aaron Hald on 10 July 2012

You're right: a little

You're right: a little citation is rarely a bad thing (blame my oversight on that trippel ale I was enjoying a little too much. ;) )

To be honest, that movie was what introduced me to the fascinating philosophical subject of change, and I thought it proper homage to quote it here.

As for the late response, there's a Shinto poem I tried so desperately to cite, for your sake I searched--I really did, (from memory, forgive me if incorrect.): 'The petal that is on the ground is the petal that is on the blossom.'

In reply to by Aaron Hald

Peter Adamson on 10 July 2012


Good aphorisms, folks! I have seen "Ghost in the Shell" once upon a time, I think, but it was a long time ago so if I ever cite it in the podcast it will be by mistake. (Actually I often worry I will mistakenly use someone else's wording without realizing it, especially writing at the speed I need to for this series... so if anyone ever notices that please let me know.)

In reply to by Malcolm

JKE on 8 July 2012

Matter and energy

Actually, matter≠energy. The upshot of general relativity is that *mass* and energy are equivalent (which isn′t even to say that they′re identical). It′s amazing how often people make this mistake!

In reply to by JKE

TD on 3 February 2014


Doesn't this mean everything is energy and its finite?

In reply to by TD

Stephen on 6 August 2016

Yes, all is energy

The simple answer seems to be yes! There was a finite quantity of energy before the Big Bang, and that's been playing out as the universe ever since. Fortunately energy can take various forms, and one of them is mass, hence Einstein's equation. Mass, unlike energy, is not conserved and can be understood as an extremely condensed form of energy. I recently read something about just how condensed that is: one kilo of sugar condenses 90 quadrillion joules of energy, that is, enough energy to lift 90 quadrillion 1 kilo bags of sugar 1 metre into the air! (all figures are approximate and subject to verification) !!!!

In reply to by Stephen

Td on 8 August 2016

I love your example about

I love your example about sugar. So facinating that energy can condense down to such a small mass. 

In reply to by Td

Stephen on 11 August 2016

Thanks, TD. Like a lot of

Thanks, TD. Like a lot of people without scientific training, I assumed there must be some sort of catch in Einstein's equation; after all, 'c', the speed of light, is a very big number even before you square it. Then I googled 'e=mc^2 Solving the Equation' and there it is: just feed in the standard units - joules, kilograms, kph - and hey presto! I chose sugar as a random kilo mass, it might just as well be feathers, wood or a puppy, but if you think about all the calories it contains ... As Heraclitus said, "Nature likes to conceal herself."


In reply to by Malcolm

TD on 3 February 2014


Malcolm, when you said "But nothing, fundamentally, is changing; it's still the same, unchanging, conserved matter-energy" it sounds like Parmenides.

In reply to by TD

Stephen on 6 August 2016

Parmenides v. Heraclitus



As Peter says in his podcast, both Parmenides and Heraclitus assert the Unity of all things as the true way of understanding. But Parmenides thinks the only way to achieve that understanding is to deny the reality of everyday experience and to contemplate the totally static oneness of Being; whereas Heraclitus embraces everyday experience as the only way to appreciate the dynamic interplay between opposite forces, that is the Logos. In fact, the more fiery activity you do, the better you will commune with the One; the enemy of truth is introspection, a 'private understanding' as he says somewhere. Does that sum up the extreme difference between their approaches to philosophy?


In reply to by Stephen

Peter Adamson on 8 August 2016

Heraclitus and experience

I think that is broadly right but we shouldn't, perhaps, exaggerate the dependence of Heraclitus on everyday experience - bear in mind he also says that most people have no understanding of the logos so his doctrine (whatever it is!) is far from an obvious inference from our experience.

In reply to by Peter Adamson

Td on 8 August 2016


Is logos = laws in nature.

One part of logos being the natural place for a pound of earth is resting on the ground and not flying up into the air?  


part of logos is that the shield you carry is never the same shield from one moment to the next?

In reply to by Td

Stephen on 11 August 2016

I'm sure it's the former.

I'm sure it's the former. Peter explains that some of Heraclitus' followers, notably Cratylus, seem to have overemphasised the idea of perpetual change - e.g. you can't step into the same river even once. But Heraclitus champions order, not chaos, and the Logos is the ordering principle that explains how stability and change coexist in the real world. Heraclitus offers a methodology: if you want to explain how the Logos is working in any thing, seek out the opposite forces that are, at least temporarily, sustaining the existence and/or purpose of that thing. I guess that he might say that a shield is most truly being itself when it is carried by a warrior into glorious battle, being hacked and dented by enemy swords! Heraclitus, like other early philosophers, is just relying upon intuition, but it's astonishing how far the 'balance of opposites' idea has driven modern science: positive/negative electric charges, magnetic polarities, planetary orbits, even Einstein's relativity: the faster you travel through space, the slower time passes!

In reply to by Stephen

Td on 11 August 2016

" if you want to explain how

" if you want to explain how the Logos is working in any thing, seek out the opposite forces that are, at least temporarily, sustaining the existence."  Say we transport Hericlitus and Parmenidies here and we show them a cup of Starbucks coffee and ask them what is going on with it.

Does Parmenidies say "yes, that is a cup and inside is coffee but the overriding reality of it is that they are the same thing, part of the same thing and yet not parts at all but just one thing which is not even moving in itself"

And does Hericlitus say "yes, that is a cup and inside is coffee but the overriding reality of it is that that cup and that coffee, if you watch it for long enough, are moving (changing)  based on the underlying order (logos)

what are the opposing forces that keep the coffee in a coffee state and the cup in a cup state. It seems that of these opposing forces one must be stronger than the other because movement is occurring. If the forces were equal there would be no movement and if no movement than no perceivable existence for those two lads to speak about or for us to message about.


In reply to by Td

Stephen on 14 August 2016

Heraclitus and Parmenides in Starbucks

Re. TD asking how Heraclitus and Parmenides would interpret a cup of Starbucks coffee.

I don't think either of them would be fazed by the timetravelling experience! Heraclitus would see signs of underlying change everywhere: the coffee burning your mouth at the counter, turning to a lukewarm milk puddle if you don't drink it fast enough; the cup a squashy bit of recycled paper (or, if you're lucky, a fragile vessel of fired clay, see nearest museum for lovingly 'preserved' Ancient Greek versions); money for drinks, drinks for money, the reliably cosy shop just the latest of a string of businesses on this spot and existing only as part of an ongoing financial strategy by Starbucks Inc. , players in an economic war that most of us would rather not think about till the next big recession. And, if we updated Heraclitus on recent success by scientists in unlocking nature's secrets, he would feel totally vindicated: everything really is moving, electrons orbiting protons at breakneck speeds even in 'stationary' objects, the heat of the coffee being the movement of molecules, in fact all heat being movement so the world really is an ever-living fire; he would say that the Logos is perfectly manifested in the laws of conservation, every joule of energy from the cooling coffee transferring to his body if he drinks it, to the shop if he doesn't.

Meanwhile Parmenides thinks it's all the same old illusion! What can you expect from 25 centuries of mortals failing to see the Way of Truth, instead mentally constructing ever more elaborate simulations based on all those opinions about opposites, becomings and non-being? Smiling smugly, he orders another cup of coffee...

In reply to by Peter Adamson

Stephen on 9 August 2016

Heraclitus and experience

Yes, Heraclitus is just as contemptuous as Parmenides about the inability of most people to understand their everyday experience. But Heraclitus supplies a methodology for interpreting experience correctly: all things are really processes, sustained by the Logos, the tension between opposite forces. For him, things simultaneously becoming and ceasing-to-be are manifestations of the Truth, whereas for Parmenides those very contradictions prove that experience is an illusion. 

I think we can see the stark difference between the two schools by comparing their use of Archery for illustrative examples. Zeno looks at a flying Arrow and says this isn't really happening, logically the arrow will never reach the target because of the infinity of mid-points. Heraclitus looks at a strung Bow and says this isn't the static object it appears to be but a battlefield of opposed tensions in the string and the bow-frame. If the string or the wood give up the fight, all you'll be left with is broken junk!

Renee Vaughn on 27 April 2014

Heraclitus and the alligators

I wanted to thank you for your excellent summary on Heraclitus. I just entered a short story contest using his philosophy from an alligator's persepctive. If I win I'll have to burn some incense to his bust. or yours!

I really love this podcast. I can send you the story if you are interested.

In reply to by Renee Vaughn

Td on 27 April 2014

Sound great. Where is it

Sound great. Where is it posted. I did something similar but from a Parmenides perspective.

In reply to by Peter Adamson

TD on 27 April 2014

The link worked

A great way of presenting philosophic ideas! You should have a contest - the listeners pick their favorite PreSocratic and then write a short story based the philosophers propositions. You could even turn it into a University course, where one day the philosophy prof lectures on the teachings of a philosopher, the next day the creative writing prof lectures on writing technique. I'd take that course.

In reply to by TD

Peter Adamson on 27 April 2014

Philosophy fiction

Yes, that's a good idea! Actually there is a book called "Thinks..." by David Lodge where pretty much exactly that happens: one of the characters is a creative writing prof and assigns the students to write pieces based on famous philosophy thought experiments (like Mary the color scientist).

In reply to by Peter Adamson

Renee Vaughn on 27 April 2014

It'd be an interesting

It'd be an interesting challenge and a lot of fun to do and teach. I hope I interpreted Heraclitus correctly!

I got the idea from reading George Eliot who was very big into philosophy, science, politics etc. Though I don't think she was all that good at alligator behavior.

Philosophy and good literature go hand in hand.

Have you any good literature professors who might guest lecture on this topic?

I can't wait for your next series even though I'm slow-walking through this course. I also sent it to a Philosophy professor friend for her students.

Keep spreading the wisdom!

In reply to by Renee Vaughn

TD on 28 April 2014

Maybe the easiest way to beta

Maybe the easiest way to beta test that idea is through online course sites like Coursera - there, there are creative writing lecturers teaching writing techniques and professors teaching philosophy - all they need to do is put the two groups of teachers together and generate the course.

These podcasts must be the best source on the Internet for such a vast undertaking. I'm slowing working through them too and trying to read the works as it flows along so I'll be through it all in about twenty years. All the while flowing from one mind state to another and at the same time not moving and always the same , Becoming in our world of sense but always Being in the finitude of infinity.

In reply to by Peter Adamson

kubelick on 8 April 2022


oh my goodness, the book sounds extremey woody-allen-ian (-esque?) thank you, peter, for the recommendation.

Zoe on 7 January 2016

Firey Souls

I find it really interesting that Heraclitus believed our souls to be made of fire. In reality, our lungs basically function the same way as fire - we take in oxigen, and spit out carbon dioxide. Just something to think about.

Brendon on 22 February 2017

well played

well played on the greek - you're spot on!  i loved this, thank you.

Axel L. on 3 May 2017


Heraclitus thinking ...sounds to me as fundametels for Hegels philosophy....

Stephen on 9 August 2018

Heraclitus in Nuclear Physics

I came across another remarkable example recently of how Heraclitean thinking - order depends on perpetual flux - permeates modern scientific theory. It is well known that all the elements which make us and most other stuff in the universe are ultimately determined by the number of protons in the atomic nucleus. This creates two problems. First, all protons have positive electric charge, like charges repel, so how can protons stay tightly packed in the nucleus and not blow the atom apart? Answer: They are ‘buffered’ by at least an equal number of chargeless neutrons. The more protons, the more extra neutrons are needed to calm their repulsive tendencies; an atom of Lead has 82 protons which need to be stabilised by at least 122 neutrons. Which leads to the second problem: outside the nucleus a proton can exist forever, whereas its heavier cousin, the neutron, has a pathetically short life of about 15 minutes before it decays into, amongst other things, another proton. Solution: Identity Swapping! The Strong Nuclear Force which continuously bonds the contents of the nucleus has the effect of making adjacent protons and neutrons exchange identities with each other; before a neutron has a chance to ‘die’, it turns into a proton; before that new proton has a chance to upset the charge balance of the atom, it morphs back again into a completely new, rejuvenated neutron ... ad infinitum. 

I think Heraclitus would be absolutely delighted to hear that not only can you never step into the same river twice, but in the atom you will never find the same proton twice!

Jonathan Doolin on 11 September 2018

Mind... Blown...

What I'm amazed by here are all the situations where the words said are so closely matched by subtle ideas in the New Testament.

2:00 On Nature:  Political Questions, the Gods.  Excerpts are one liners--riddles.

The road up and down is one and the same.

Nature knows how to hide.

Heraclitus the obscure.

3:15 In the opening passage.  Logos: Word, Account, Reason, Proportion, Measure

Theology is giving a logos of God

Anthropology - the logos of man

3:56 Here in Heraclitus it becomes crucial

Logos is what no one understands even though evidence is staring them in the face.  It explains everything in nature, or "fusus"

4:30 Hearing not me but the Logos, it is wise to agree that all things are one.

Distinction Listening vs. Hearing.  (This is an element of the prophesy of Isaiah--the idea that we shall forever be hearing, never understanding.)

Interpretation 1:  You should not believe it because I am saying it, but because it is true.  

Distinction: Account or Proportion that binds all things.

Interpretation 2: First endorsement of Monism--theory of parminedes, who rejected the idea that there are many things.  

Interpretation 2:  Things (plural) are One (singular.)  (This is central to John 1.  In the beginning was Logos.  Through it, all is made.  ) 

Core idea:  Unity of opposites.  One liner riddles.  Seawater poisons humans, but fish need it to live.  Donkeys prefer garbage to Gold.  The road up is the same as the road down.  (This is what Jesus says to Nathanael, in John 1 -- You will see Angels ascending and descending on the Son of Man.)

Not everything is this way.

8:05 A salad vinaigrette's nature is united when stirred.  But separates when left undisturbed.

8:50 Heraclitus said there was no unity/stability?  You can't step into the same river twice.  This creates contrast to Parminedes--who thought change was an illusion.

9:50 The flux interpretation of Heraclitus is wrong, and due to Plato.  

10:10 Cratelus held that it was impossible to name anything... you can only point at things that are melting one into another.  Heraclitus believed it was the same river... The saying is "Different waters flow over the same rivers... Same river, different waters each time"

13:00 the reason the moon waxes and wanes is that a bowl is slowly turning.  Stunning night sky; no light pollution.

14:00 Souls are made of fire when alive, and they are wet and put out when dead.

15:00 Abstract conception of dry warm fast-moving stuff is the most exalted stuff, and we share our nature with the divine.

15:20 Asked to write a set of laws, he said he would rather play with the town's children.  (From Matthew 18:3 And he said: “Truly I tell you, unless you change and become like little children, you will never enter the kingdom of heaven.  Matthew 19:14 Jesus said, “Let the little children come to me, and do not hinder them, for the kingdom of heaven belongs to such as these.”)

16:20 A professional philosopher... Heraclitus had something to say about every philosophical subject.  Ethics and the study of human nature are interrelated.  It was Heraclitus who really engaged in this systematic way.  

Michael Aparicio on 28 March 2021

Is Fire a symbol?

Another thoughtful episode. 

Two questions this time. 

The textbook I use refers to Fire as a symbol for The Logos.  Do you have thoughts about how to understand Fire and Logos? 

Second, the textbook makes a provocative connection between the many's inability to discern the Logos and their tendency to maximize bodily pleasures,  citing Heraclitus comparing the many to cattle. It seems to imply that the ability to pursue wisdom successfully relies on one's ability to live ethically. Is this an overly speculative interpretation of Heraclitus? 

Thanks again, 


In reply to by Michael Aparicio

Peter Adamson on 28 March 2021

Fire in Heraclitus

Yes, good questions and not easy to answer! People have read Heraclitus both ways, I mean taking fire as merely a metaphor for logos and taking it as literal fire (as the Stoics did). I would lean towards saying both, I guess: he has a literal cosmology with fire playing a key role but he would say that fire is a paradigm case of a more general phenomenon of a dynamic bond between things.

And similarly I would say that for him ethics goes hand in hand with knowledge more generally, so I would resist the urge to divide the pursuit of wisdom apart from the pursuit of ethical goodness as if these are two separate enterprises for him.

Jordan on 16 November 2021

I love this! I have been…

I love this! I have been meaning to look up Heraclitus but it's hard to glean from short bios. 

It's also awesome to be able to synthesize these ideas - I have been trying to study Jewish philosophy, but they did take a lot of stuff from the Greeks, and their ideas were taken (along with Greek ones) by the Christians in turn. Hence, "In the beginning was the Word, and the Word was with God, and the Word was God," where the Word is supposed to be Jesus.  

This week in Torah study we looked at a quote involving "holy knowledge" called "daat," which my rabbi explained referred to the knowledge of good and evil in Genesis. 4:30 sounds like that. 

I do think it's easier to sound wise if you don't say too much... Not that I put that into practice.

Grisy Trujillo on 19 July 2022

Thank you and an observation.. how deep is his fire?

Thank you so much for doing this. I can’t believe how much I love it. Heraclitus is by far my favorite although Xenophanes is close! I’m skimming through H’s fragments before I read them just for quick glance and I found this one, I’ll probably regret saying this after I send it haha. I’m in kindergarten when it comes to philosophy and the same goes for physics but this fragment I ran into resonates with the theory of matter being neither created nor destroyed. I thought.. it seems obvious to me because I’m simply looking at things in retrospect through this tiny pinhole haha…  

-This order, the same for all things, no one of gods or men has made, but it always was, and is, and ever shall be, an ever-living fire, kindling according to fixed measure, and extinguised according to fixed measure.-

how deep is “fire” for Heraclitus?As deep as the deepest for every human, I’d say, the cosmos and the soul 🥸

Kester on 8 October 2023

Heraclitus in modern poetry

Hi there, I'm enjoying the series a lot. My specific enquiry as I listen is about how thinkers of the past have shaped the way I and others think today. As a writer, I feel I have a responsibility to understand why I think the way I do. I don't know how much of pre-Socratic thought can truly be found in modern poetry, but I could not help seeing Heraclitus in Langston Hughes' joyful poem Harlem Dance Hall, in which the dance floor takes on a new and distinct identity when everyone is dancing ("...when the band began to play, / Suddenly the earth was there, / And flowers, / Trees, / And air, / And like a wave the floor - / That had no dignity before!") or in RS Thomas' harrowing poem Reflections ("[your reflection in the mirror] is a chalice / held out to you in / silent communion, where gaspingly / you partake of a shifting / identity never your own." -- to put it in Heraclitan terms, perhaps he is saying that the identity offered you in your reflection and your actual self are 'different waters in the same river'.) I have never successfully studied philosophy before so I would be delighted to hear anyone's thoughts on the matter.

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