The earliest Greek philosophers were particularly interested in the physical world, and what it what it might be made of. Water, said Thales. Air, said Anaximenes. Something “unlimited” (i.e. something unlimited by such specific features as characterised things like air or water) said Anaximander. It took a subsequent philosopher, Xenophanes, to suggest that there is no means of knowing the truth, on these or any other topics; all we are presented with are the appearances of things, how they “seem” to be.
At this stage two of the greatest philosophers before Socrates — Heraclitus and Parmenides — appear on the scene. Both are aware that they cannot avoid Xenophanes’ challenge; if he is wrong about the impossibility of knowledge, they have to refute him with argument. While they disagree with each other on a number of details, they seem to have agreed on the following fundamentals.
Knowledge in the strictest sense is — against Xenophanes — possible, but it is always of something general or universal. In the case of the world, this can only be known when viewed as a whole or in its totality (Parmenides), or to the degree that it can be quantified or measured (Heraclitus); everything else about it can only be the subject of opinion.
For Heraclitus, knowledge and a rational account (logos) of the world go hand in hand; this is true both for his own account of the world and for the world’s account of itself.
The relationship between knowledge and the world, and between a number of supposedly opposing features of the world, is one of necessary interconnectedness, says Heraclitus, boldly described in terms of identity. Parmenides, carrying the idea over into epistemology, describes epistemic interconnectedness with an equally bold assertion of identity: “knowing and existing”, he says, “are the same”, a sameness which should clearly be understood in the sense pioneered by Heraclitus, that is, that knowing something, and that thing’s being the case, are necessarily interconnected. (If the point seems too obvious to spend time on, one needs to remember that there had to be a first person to say it.)
Let us look at these ideas in a little more detail.
Writing shortly before Heraclitus, the philosopher Xenophanes expressed doubts about whether knowledge of anything — as distinct from mere opinion about it — was possible, and as far as we know he was the first philosopher to express the point with clarity. “No man”, he says, “knows or will ever know the truth about the gods or about everything I speak of. For even if one chanced to say the complete truth, one is not oneself in a state of knowledge” (i.e. as to whether one has chanced upon the complete truth, or — more generally — as to what one claims to know); “for seeming blankets everything” (fr. 34). (All references in the article are to the Diels-Kranz edition of the fragments of the Presocratics).
One direct result of Xenophanes’ scepticism was an onus felt by his successors to show their hand on the matter, on pain of seeing their own work written off as just another set of opinions if they did not. It comes as no surprise therefore to find both Heraclitus and Parmenides expressing themselves forcefully on the topic in the early stages of their respective books.
For Heraclitus the account (logos) of the real (which he also calls “this world-order [kosmos], without beginning or end” [fr.30]) is an everlasting, true description of the nature and processes of a world that, despite constant major change in respect of its parts, is fundamentally a unity (fr. 50), and will remain so everlastingly. By world, it should be added, he means not only the physical world but also the sum total of facts concerning the world, including perspectivally-based facts, such as “A way up and a way down are one and the same” (fr. 60). The account in question is not his own, except derivatively, but rather that being broadcast everlastingly by the world itself for the benefit of anyone who takes the trouble to learn its language. If his view sounds pantheistic, it probably is; elsewhere (fr. 67) he suggests strongly that this world is, to use his own word, “divine” (fr. 67). He was also not unique in his pantheism; an articulate antecedent was the philosopher Xenophanes, who expresses similar thoughts in some remarkable verse [frs. 23, 24, 25, 26])
The road to knowledge of the world’s descriptive account (logos) of itself is a long and hard one, but at its end, says Heraclitus, insight into, or “coming to awareness” (noos) (fr.114) of the contents of that account, is finally achieved, and, along with it, a realisation that the account also has a prescriptive component, the divine law of conduct “which nourishes”, he says “all human laws” (fr.114). This is clearly of great importance to him, allowing him to say elsewhere, “The people must fight on behalf of the law as though for a city wall” (fr. 44). For his younger contemporary, Parmenides, likewise, the real is knowable, but in his case it is only the world as a totality (pan) which is so knowable, not the diverse world which presents itself to sense perception. This world-as-a-whole is also, as it is for Heraclitus, without beginning or end and changeless as such (frs. 8.3 ff., 8.26 ff.). And the true account which describes this real is again, derivatively, that of Parmenides himself, but at base it is, analogously to that being uttered everlastingly by Heraclitus’ “divine” universe, the account propounded by a divinity, who, in propounding it, is also thereby the guarantor of its truth (fr.1).
For both philosophers there is only one route that can possibly be followed if knowledge of the real is to be attained. For Parmenides it is the route of “is” and “necessarily is” statements (fr. 2.3), and its end-point is a reality-as-a-whole (fr. 8.5) that is, as he puts it, both ascertainable by the mind and “pointable-to in words” (fradzein)” (fr. 2.7-8). For Heraclitus it is that route, open or “common” to all humans (fr .2), which consists in listening to what the real (for him, the universe as perceived by us) has to say about itself after learning the language in which it is everlastingly expressing itself concerning the world-order in all its aspects. Eyes and ears and the other senses, he says, may be our best indicators of the appearances of things and their noises and smells and the rest (fr. 55), but they are still a poor guide to knowledge of them if inquirers do not have minds that understand the language the world is speaking (fr. 107).
Once one learns this, one will discover, among other things, that perspective offers a useful pointer to understanding. So, a road up and a road down can the same road, depending on perspective (fr.60); for example, sea water is good for fish to drink, but bad for humans (fr. 61). Other things are understood more clearly if seen in pairs: e.g. the combinations day-night, winter-summer; war-peace; satiety -hunger (fr. 67). In many other respects, however, nature hides its constitution from us (fr.51), and many of its connections are obscure (fr.123). Nonetheless, the world coheres, somehow, in a state of balanced tension, like the tension between the strings and arc of a bow or the strings and frame of a lyre (fr. 51). As a variant on the concept of tension, he says elsewhere that war and strife are at the heart of things (frs 53, 80).
At various times, he suggests, we will stress the world’s unity, at other times its diversity, and at other times its unity amid diversity. A good example of the latter is to be found in the so-called “river-image” (fr. 12): “Upon those who step into the same river different and different waters flow… It scatters and… gathers… It comes together and flows away… approaches and departs” (tr. Raven). The simple and powerful point is that a river is a unity despite the constant changing of its waters. And this is the version of the image that should be accepted — with apologies to all for whom it is the only thing they thought they knew about Heraclitus — over the more famous but almost certainly apocryphal version attributed to him that “[W]e step and do not step into the same rivers; we are and are not” (49a). (Though some may feel a little better knowing that Plato too took it to be genuine [Cratylus 402a], or at any rate the first part of it.)
Like his cosmologist-predecessors, Heraclitus is interested in what the world is made of, and his own particular choice is “Fire”. In a powerful fragment he says: “This world-order… always was and is and always will be: an everlasting fire, kindling in measures and going out in measures” (fr. 30, tr. Kirk); elsewhere he tells us that sea and earth are manifestations of what this fire turns into when it is temporarily “out” (fr. 31). The concept of “measure” here, like those of “tension” and “connection” (harmonia) in other fragments, is critical: the connection between what he himself calls “things conjoined” or “things going together” in the world and other early philosophers call “opposites” is clearly for Heraclitus something measurable, the way the tension between the strings and the arc of a bow is measurable. Measurement is clearly a concept he finds important; elsewhere, he talks about how “Sun will not overstep his measures” (fr. 94), or, if He tries, the higher law of the Justice of the universe will find him out (ibid.).
Why is any of the above philosophically interesting? To answer this question one must look at the context. In the half century of so antecedent to Heraclitus there were only four philosophers, and all of them, without benefit of microscope or telescope, had concentrated on physics and cosmology. Heraclitus is a cosmologist too, but his break-through is more significantly epistemological. On the face of it, it is bizarre to claim we learn about the world by listening to its never-ending self-description. But understanding the “governance”, as he puts it, of all that constitutes the world is, he says very forcefully, the one true form of wisdom (fr. 4). And the cosmic counterpart of such wisdom is that “one wise thing” which “is and is not willing to be called by the name ‘Zeus’” (fr. 43).
Heraclitus was known in antiquity as “the obscure”, and this could well be seen as an example of such obscurity. But I suggest that it is not, if we take science and mathematics, summed up in his own words as the “measures of” (ways of measuring?) things, as our guide. Looking at the (to the naked eye) unchanging and predictable movements of the stars and planets, the seasons, and the like, he concludes, like most thinkers till the sixteenth century, that all of it is governed, but differs from most in saying that such governance is self-governance. We ourselves, in our less guarded moments, continue to talk about the “laws of nature”, a phrase which Heraclitus would probably have accepted, given that the word logos, so central to his thinking, can in various contexts mean “law” as well as “account”. In view of his comment on the “divine law” nourishing all human laws (fr. 114), he might well have been saying that careful observation of the world was the best way of accessing both the physical laws of how it governs itself, and also, prescriptively, that moral law which is the basis for sound human laws (ibid.).
Such observation, as we saw, is for Heraclitus pre-eminently with the ears, especially when we want to know more about the world’s macrostructures and processes: we listen to what the world is telling us. If this possibly surprised many of Heraclitus’ first readers, it should surprise us much less, used as we are to learning from radio-telescopes a mass of information conveyed to us by the “speech” of the universe, radio-waves. Equally unsurprising should be his choice of fire as the most basic of the elements. As a pantheist, he was looking for an element in nature best exemplifying its dynamic (in his word, “divine”) character, and fire clearly seemed to him the most obvious contender for the title. To the best of our knowledge, the word “energy” had not yet appeared in the Greek language, but it seems reasonable to think that, had he had the word at his disposal, he would have made use of it in his many comments on fire’s power in the universe. And who knows? Given the massive transformations of matter into fire through the process of combustion (frs. 30, 31, 90), he might well have found it not at all surprising that one day people would have taken a step beyond him, and talk of energy as being the basis of the real, manifesting itself in various forms, one if which is the “frozen” form of physical matter.
Returning to his interest in measurement, Heraclitus clearly felt that, not only was the language of the universe in some way hearable by us, it was couched in terms accessible to our mathematical sense. This was a move a Greek philosopher could make with relative ease, since one of the many senses of logos is “ratio”, and the ratio of season to season, day to week, week to year, of star to star within the various constellations, and so on, was part of what struck him as the massive unity amidst diversity which constituted the universe.
In a world then only at the very beginnings of epistemology, he might also have felt that listening to, and observing the universe was our best chance of achieving knowledge, rather than being forever bound by opinion about the way things are. As he himself puts it, while “Nature has a tendency to hide itself,” (fr. 123), it nonetheless, in its ongoing self-descriptions, invariably “gets it right” (fr.78). Likewise, the radio-waves continuously being emitted by Alpha Proxima Centauri invariably constitute a true description of itself; we ourselves achieve knowledge (not just an opinion) of this when, by various techniques of mathematics and measurement, we succeed in accessing the precise aspect of the star that radio-waves convey. And that aspect is the star qua quantifiable, qua measurable.
We are looking here at the first attempt by a Greek philosopher to show that Xenophanes’ scepticism about our attaining knowledge of anything is too pessimistic. There are things we can know, in the way the world itself knows itself, and that is the quantifiable and measurable aspect of the real. A generation later Parmenides will also claim that knowledge is possible, though it will be much more confined in its range than it was for Heraclitus; knowledge (as distinct from opinion) will be confined, not to the real qua quantifiable and measurable, but to the real simply qua real, and in its totality. So, the real qua real and in its totality will as such not collect a history, though everything composing it will; it will as such be homogeneous, though everything comprising it will be differentiated, and so on (fr. 8). But that is another story. As far as Heraclitus is concerned, his epistemological optimism is unfortunately, it seems, less robust than it might appear at first glance, since he has no confidence that other humans than himself can ever achieve an accurate understanding (fr.78) of what the world is telling them about itself, even if they do manage to tune in to its wavelength (in his own words, “to hear”) what it is telling them [fr. 1]). Hence his book, which will attempt to put into accessible human language what, in another language, the world has to say about itself.
Disappointing as it is to find that, in the end, what Heraclitus offers us as the bedrock of his philosophy is a pair of arguments ex auctoritate (for Heraclitus himself the authority of the universe, for the rest of us the authority of Heraclitus), it is still worth looking at what his claims are in their own right, regardless of their putative provenance. Because his is the first known attempt to set out in detail a doctrine of the ceaseless flux of matter in the world in combination with a principle of order within it such that it constitutes a unified whole.
Macroscopically, the world’s processes are highly predictable (or so it will be thought before the invention of the telescope) even if microscopically it is forever in flux.
Across the years many philosophers will go on to elaborate systems that are basically variants on this theme of changelessness amidst change, the totality directed by a governing principle either from within or without. As such the doctrine (and its variants) will constitute one side in a battle which it will go on lopsidedly winning for over two thousand years. The opposing side, almost totally ignored from its beginnings, were the early atomists Leucippus and Democritus and their followers, who firmly maintained that there was no “governance”, external or internal, of the universe; all that is real are the everlasting, haphazard couplings and un-couplings of “basic bits” of matter colliding indiscriminately in empty space. But everything changed in 1610, when Galileo first glimpsed through his telescope four moons orbiting Jupiter, and perceptive thinkers realised at once that the Aristotelian variant of Heraclitus’ views, which had placed the directive force of the universe in a sphere, beyond the moon, of a supposedly fixed and unchanging number of celestial objects, had been grievously, if not mortally compromised, and the way was open for the long-forgotten Atomists to stage a comeback. And stage it they did, with what they now felt were much stronger weapons. And the battle – for many, one of the biggest, if not the biggest, of all philosophical stand-offs – is still joined.