Br. Anthony Nguyễn Phượng Hoàng, S.J,
Junior Scholastic of the Philosophy program

Abstract: This essay, mainly bases on the explanation of the saying which is attributed to Heraclitus: “It is not possible to step twice into the same river.” (DK 22B91)[1], aims to characterize some crucial elements in his philosophical principles regarding change and its consequences. From there, our essay will be divided into three sections: the meaning of the flux of change will be discussed in flux section, the main content of fire section is how the process of change operates and what controls this operation will be mentioned in the logos one. Ultimately, to discover the very essence of change in Heraclitus’ thought is the main target of this essay.

Keywords: Flux, change, fire, Heraclitus, logos.

“It is not possible to step twice into the same river” – Heraclitus (Internet)


Heraclitus (c.540–c.480 BC) is one of the greatest Greek philosophers, who lived and flourished around the beginning of the fifth century BC, in Ephesus (near modern Kuşadası, Turkey). He is best known for his doctrines that things are constantly changing (universal flux), that opposites coincide (unity of opposites), and that fire is the basic material of the world. His dates of birth and death are based on a life span of 60 years.[2] We really know nothing of his life, except, that he perhaps belonged to the ancient royal house.[3] Apparently, his main thesis is “it is not possible to step twice into the same river.” (DK 22B91) This quote, one of his most famous saying, is attributed to Heraclitus since the time of Plato. However, this paper will discuss not only this quote, but other comparative fragments in order to, somehow, provide a possible explanation. It therefore will be concentrated mainly on the flux of change, how the process works, and what rules over this procedure.


Heraclitus was famous for stressing the flux of things. It is no doubt that the concept of flux or change occupies the primary place in his philosophy. He proposed the affirmation that the subject and object are changing whereas both seem to remain the same.

First of all, the subject is changing, says Heraclitus, “into the same rivers we step and do not step, we are and we are not.” (DK 22B49) A human body could be understood in the same way, as living and continuing by virtue of constant metabolism. On this reading, Heraclitus believes in flux, but not as destructive of constancy; rather it is, paradoxically, a necessary condition of constancy. He argues that the constant change that people undergo at all times can be explained by being subjected to new and different experiences all the time. Inevitably, as each moment passes on, our awareness changes and gets knowledgeable by our experiences. Moreover, our body and mind in terms of psychological, sociological or even spiritual aspect are actually changing. And so, the apparent permanence of material bodies is actually temporary in nature.

Secondly, it is true that the river, mentioned as the object, also changes. In fact, the relative change between the two rivers (pre-stepped into in comparison with post-stepped into) is not usually perceived, and so people are given the impression that it is the same river, when it has actually changed. This change does not become apparent as a literal change which people are unable to recognize entirely, but it is different to it, before. In this way, permanence of material objective is actually temporary. Heraclitus says “upon those who step into the same rivers, different and again different water flow.” (DK 22B12) Obviously, all things pass and nothing stays, and comparing existing things to the flow of a river. And so, it is not simple that all things are changing so that we cannot encounter them twice, but something much more subtle and profound. It is that some things stay the same only by changing!

Finally, despite the fact that both subject and object are changing, somehow they paradoxically continue the same. The first point is that the flux of change takes on many different forms. Nevertheless, there are certain something which continue to be the same through all the flux of change.[4] We might consider that “we return to the same river although flesh waters have flowed into it, and the adult is still the same person as a child. Things change and thereby take on many different forms, but, nevertheless, they contains something which continues to be the same throughout all the flux of change.”[5] For example, the fire, as we will discuss later, is perpetually becoming water, and earth; but, as the opposite process goes on at the same time, they appear to remain the same. The second point is that the change is not opposed but closely connected as “the road up and the road down are one and the same” (DK 22B60). So people can speculate that “we are and we are not” and “the river is and is not”. Remarkably, there are typical kinds of coincidence of opposites which Hegel most admired in Heraclitus. In fact, the process and the nature of the flux of change need to be considered in comparison with the fire in virtue of “the change in itself a material cause and therefore is represent in the philosophy of Heraclitus by the fire as the basic element, which is both matter and a moving force”.[6]


After explaining everything changes, to describe how the process of change operates seems to be another chief goal of Heraclitus. In order to give an exact characteristic of change as unity in diversity, “Heraclitus assumed that there must be something which changes, and he argue that this something is fire.[7] We now come to the most mystifying aspect of Heraclitus’ thought. It is noticeable that fire for Heraclitus does not seem to be unlimited (as Anaximenes’ air is, for instance), but in its very essence. For this reason, fire gives us both a symbol of constancy and a key factor to explain the one in many.

On the one hand, fire seems to be a symbol of constancy in change. The first point that people need to concern is the continuity of this process. Heraclitus realized that the fire is a process of transformation and what is fed into it is transformed into something else. In fact, it is easy to see why, if we, for example, consider the phenomenon of the process of burning. The process in a flame burning steadily appears to be continuous. It is always passing away in smoke, and its place is always being taken by fresh matter from the fuel that feeds it. If people regard the world as an “ever-living fire” (DK 22B20), “we can understand how it is always becoming all things, while all things are always returning to it.”[8]  The second point is that while seeming to be in motion, there is still the unity of the fact that it remains fire, and the proportionate balance between the flames and the fuel.[9] There is a kind of conservation of matter, or at least overall quantity of matter. For instance, what would make the world to be continuous would be the fact that when one portion of fire turns into water, an equivalent portion of water turns into fire. The overall balance is preserved, even if the water that is now in the sea is not the same water as was in it before. This idea brings a similarity to the image of the river, which remains the same although the material contents changed. As a result, the mutual transformations, or the change, of matter are not an accidental feature, but the very essence of nature: “without change, there would be no world.”[10] All this made it necessary for him to seek and find out a new primary substance: “Fire is itself a paradox, and serves as both a symbol and a major constituent of the paradoxical world.”[11]

On the other hand, fire is also a key factor to explain the one in many regarding change. Heraclitus recognized that the movement of fire which called the “upward and downward path” consists the flux and change. On the latter path, as we mentioned above, fire is condensed it becomes moist, water and then earth. On the former path, this processed is reserved, the earth is transformed into water and various forms of life. By this way, Heraclitus believed that he had explained the principle of the unity between the one basic stuff and the many diverse things in the world. As a matter of fact, “he fastened upon fire as the basic reality, he not only identified the something with change but he had also discovered the principle of change itself”.[12] For Heraclitus, the world is at once one and many; it is just “the opposite tension” of the opposites that constitutes the unity of the One.[13] This change springs the belief that there is one fundamental principle which controls all movements as he call logos.


The process of change is not an accidental movement but the product of the universal Reason (logos). However, we just have intention to consider some crucial points of logos regarding change instead of analyzing all characteristics of logos.[14] Therefore, the universal and immanent dimension of logos will be discussed as the essential ones.

Firstly, the first characteristic of logos is universal. Heraclitus believes that fire is the only basic reality which he calls logos (cf. DK 22B67 and 22B32). Because God, the logos, is Reason and permeated all things, it leads him to believe that God is the universal Reason which control all things to move and change in order and create the essence of law.[15] Moreover, all people are received this universal law from the Reason because they have fire in their own nature and they, in turn, have ability to thought and act according to the universal law. Obviously, he affirmed this idea in his fragments “the idea that all things come to pass in accordance with this logos” (DK 22B1) and “the logos is common” (DK 22B2). According to the truth of the logos, all is one and there is proportion or harmony throughout the world[16] in order to keep all things change.

Secondly, another characteristic of logos is immanent but partly comprehensible. The first point is that the logos, the truth of things, is common and universally understandable. It is not only different from anything else but also unfamiliar and unexpected. The logos which takes place as a combination of seemingly contradictory phenomena and thus becomes the shared feature of these phenomena, affirms itself as a movement or a change.[17] The second point is that humans always prove unable to fully understand the logos. For though all things come to be in accordance with this logos, humans are like the inexperienced when they experience such words and deeds. Some people fail to notice what they do when awake, just as they forget what they do while asleep (cf. DK 22B1).

Finally, we are impelled to consider logos in comparison with human being in its nature. For Heraclitus, all rules of human beings have one heavenly source the logos, and logos is the central idea of fundamental importance for both the uncovering of the Being and human being.[18] In reality, a right way of thinking or the greatest virtue of human beings can be understood by fighting against the change of self-increase. The change could have two dimensions: its common in human beings in general and the strength of one’s own thinking in particular. Consequently, we can consider that flux of change in Heraclitus’s thought not only based on the physical movement but approached the question of being which developed by later philosophers, especially in Heidegger’s thought.


In summary, to explain the change in its very essence has been one of the most challenging problems in the history of philosophy through all ages, Heraclitus has said: “It is not possible to step twice into the same river.” By his philosophical thoughts, he gave us a persuasive explanation which based on the operation of fire and the decisive role of logos in the process. Whether we agree entirely with his idea or not, considering this quotation could be enormously valuable “the same thing is both living and dead, and the walking and the sleeping, and young and old; for these things transformed are those, are those transformed back again are there.” (DK 22B88).

[1] In this essay, we use a version of the fragments according to the arrangement of Diels/Kranz (DK). The English translation of the fragments can be found in the edition by S. Marc Cohen, Patricia Curd, and C.D.C Reeve, ed., Reading in Ancient Greek Philosophy: From Thales to Aristotle (Indiana: Hackett Publishing Company, Inc., 1995).

[2] Michael Gagarin, ed., The Oxford Encyclopedia of Ancient Greece and Rome (New York: Oxford University Press, 2010), 29.

[3] Jonathan Barnes, Early Greek Philosophy, 2nd ed. (London: Penguin, 2001), 96.

[4] Samuel Enoch Stumpf, Philosophy: History and Problems, 7th ed. (New York: McGraw-Hill, Inc., 2007), 13.

[5] Stumpf, 13.

[6] Werner Heisenberg, Physics and Philosophy: The Revolution in Modern Science (New York: Harper & Brothers Publishers, 1958), 63.

[7] Stumpf, 13.

[8] Barnes, 106.

[9] Robin Waterfield, trans., The First Philosopher: The Presocatics and Sophis (New York: Oxford University Press, 2000), 34.

[10] Daniel W.Graham, “Heraclitus,” Stanford Encyclopedia of Philosophy, September 3, 2019, (accessed November 24, 2019).

[11] Waterfield, 35.

[12] Stumpf, 13.

[13] Heisenberg, 62.

[14] There are the considerable number of ways to explain the literally meaning of logos.  Later Stoics, Marcus Aurelius for example, understood logos as “the account which governs everything” in Marcus Aurelius Antonius, Meditations (Oxford: Oxford University Press, 1998), 19.

[15] Stumpf, 14-15.

[16] Waterfield, 33-34.

[17] Viktoria Bachmann, “The Human Being According to Nature. Self-enquiry with Heraclitus,” Ápeiron. Estudios de filosofía, no.11 (October 2019): 144.

[18] Stavros J. Baloyannis, “The philosophy of Heraclitus today,” Encephalos, no.50 (2013): 1-21.

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