Last week you were introduced to the first beginnings of Greek philosophy, and I tried to show how relevant this philosophy is to you, since your own present day world picture is to some extent a product of it. I tried to show you how the way the Presocratics thought about the world is much the same as ours, not only in the beginning of the development of scientific and rational thinking, but more importantly as the laying of the foundations of the fundamental language which we use to express our basic experience of the world; a language that I called metaphysics. I also put forward the claim that this view of the world, which is still today our world-view, is greatly different from the mythical and religious conception of the world that you find in the first verses of Genesis, for example, or the poems of Hesiod.

In the next two weeks, we shall look at two of perhaps the most important Presocratic philosophers, Heraclitus and Parmenides. They are important for us because they were significant influences on the thought of Plato, but also because they offer two very different versions of philosophy, which is still the main fault line within philosophy today.

Heraclitus was born in Ephesus at the end of the 6th and beginning of the 5th century BC His writings are even more gnomic than the already obscure writing of the Presocratics as whole. Again, like the other Presocratics, we only know of Heraclitus through the summaries and quotations of his works made by other philosophers long after his death.

One of these philosophers, who is the greatest source of our understanding of Heraclitus, is Plato himself, because he saw one of the main aims of his own philosophy was to defeat the scepticism that he believed was the inevitable consequence of Heraclitus’ way of thinking. Because Plato saw Heraclitus as his opponent, he tended to give only a one-sided view of his philosophy. But because this one-sided view is the way that Heraclitus has passed down into tradition, because of the fame and influence of Plato himself, it is worth, first of all, examining this interpretation.

At the heart of Plato's interpretation of Heraclitus is the fragments concerning the river, which some of you might have heard before, since it is the most famous of Heraclitus’ images.

Plato himself describes the same image as follows:

Now how does Plato, and those after him, who took his interpretation of Heraclitus to be right one, understand this image of the river? They understand Heraclitus to be saying that the world we see with our senses is constantly changing, like the river flowing past the onlooker. All the things that exist are coming into existence or going out of existence. To our uneducated person it might appear that existence is stable and permanent. I look at the chair in front of me and then I look at it again, and it still appears to me as the same chair. But this is an illusion, for even in that small period of time it has undergone imperceptible changes. And this is true not only for this individual chair, but for all existing things and for the universe itself in which these things exist.  To use Aristotle’s example in the  Physics, reality is like a rock being worn down by drops of water, although in the moment in which we are looking at the stone nothing appears to be changing, when we return months or even years later the rock has been hollowed out by the water. What appears stable on the surface to the uneducated human eye conceals continual change.[3] The physical material world is neither stable nor permanent; it is the world of becoming and movement. It is another dialogue by Plato, the Symposium, where we can find have a excellent description of this unstable world of change:

This seems a plausible explanation of reality. So why would Plato believe that the consequences of holding it to be so dangerous to the ambitions of a rational account of the universe? Because, if this flux of change were the only possible description of existence, then knowledge would not be possible, since knowledge depends on permanence and stability. It appears that the necessary outcome of the doctrine of flux is scepticism. How would it be possible to define anything, if as soon as I called it a name, it changed into something else? A disciple of Heraclitus, Cratylus, took this doctrine so far as to assert that the only credible position would therefore be silence.[5] How could one know something truly if it were always changing? Common sense would not have a problem here, since it lives in the world of change as though it were permanent and stable. But the knowledge of which Plato speaks, which according to him is the highest desire of the human soul, is scientific and philosophical knowledge. This knowledge can only be true knowledge if what it asserts is not merely true for one moment of reality, but for all time. Thus, he needs to show that Heraclitus’ description of a constantly changing physical universe cannot be the description of what reality is. He does this not by discounting that the physical universe is changing, which would be to return to the ignorance of the common man, but saying that knowledge is not dependent on this sensible reality of change, but another realm of existence altogether, which is the realm of the Forms or the Ideas, and which is, on the contrary, eternal and immutable. We shall examine this theory later in this course.

But has Plato given us the whole story of Heraclitus? I think not. He is only giving us one side. For although one side of Heraclitus’ philosophy is that everything is changing, the other side is that within this change there is unity and it is this speculative synthesis of diversity and identity, or order and chaos, as we would say in our modern jargon, which is entirely missing in Plato’s account. This speculative synthesis is Heraclitus’s doctrine of the logos (remember this word from the first lecture?). Unity within change and change within unity, this is the pattern or the law of the universe for Heraclitus. He wants to say that this pattern is not visible to everyone. ‘Nature’, he says ‘loves to conceal itself'’.[6] It is for this reason too that Heraclitus writes so enigmatically and obscurely. Nature’s concealment means that it is not open to everyone to know its truth.  Heraclitus writes, “Most people do not understand the things they meet with, nor do they know when they have learned, but they seem to themselves to do so.”[7] Again it is a question of looking deeper into things than we normally do. First of all we need to go beyond the false stability of common-sense, and realise that beneath the apparent stability of things there is only becoming, but then we need to look even further, into the becoming as well and realise that all existent things in the world are this one and the same becoming which is constantly changing and this one and the same becoming is the universe.

The one mistake we can make here is to think that the difference between the one and becoming is a difference between two different levels of being, which would be precisely to read Heraclitus through Plato’s eyes. This would mean that becoming would be one level of being, corresponding to the physical world, and the unity of becoming would be another level of being, corresponding to the logos, to thought. But Heraclitus is not a dualist. He has no sense of a world down here, which would be finite and changeable and another world beyond this world, which would be eternal and immutable. As we shall see, this division between two worlds does not appear in Greek philosophy until Parmenides and is only consolidated as a world-picture by Plato (this kind of world-picture has, of course, important consequences for the development of Christianity). For Heraclitus there is only the one world: the one universe, the one cosmos which is at one and the same time changing and the same. One can imagine it as follows: from the perspective of separate things in the universe everything is in flux and in motion, but from a different perspective, from the perspective of the whole, which is the sum of all these different things, it is the same which changes, but even though it is changing, it still the one and the same. This is a very paradoxical and difficult thought, and Heraclitus does not make it any easier for us in the manner in which he describes it:

The oneness of the universe is not to be though through the image of a fixed and frozen identity, but as the unity of opposing forces. Becoming is not only to be understood as one thing changing into another, but also as the conflict between one thing and another. One thing changes into something else, because of the force of another thing. A rock slowly changes its shape by the pressure of the water that is flowing across it. From one perspective, the world then appears to be disordered and all things are constantly at war with one another. But from another perspective, the perspective of the one, all opposing forces in the world balance each other out, and out of this strife is created harmony and equilibrium. Unlike the Pythagoreans, this harmony for Heraclitus is not external or beyond the world of opposition and strife; it is this world seen from another perspective. Again Heraclitus can only express this difficulty idea through an image:

The one, the law, the unity, the logos, the sense, direction of the universe is not something external to it, but immanent. The logos and becoming are one and the same thing, looked at from a different aspects. The one is not above becoming; it is becoming, just as becoming is not below the one, but is the one. There is a verse of Wordsworth’s poem Tintern Abbey that seems to be to capture a part of what Heraclitus obscurely communicates to us of the mysterious and mystical unity of all things: