Philosophy

6

LECTURE: The Pre-Socratic background to Aristotle

Some varieties of dualism

We saw last week that, in the history of philosophy, there have been two main competing views about the mind-body problem. On the one hand, there is materialism, which holds that matter is all that exists, so that the human mind must be identical to the brain or to some other purely physical aspect of human nature. On the other hand there is dualism, which holds that mind is not reducible to matter, so that there are two irreducibly different aspects of human nature – material and immaterial, physical and non-physical, body and soul. There are other views too, and nuances to these two views, but that’s the main debate.

We’re going to start the semester by looking in depth at dualism, and we’ll come back to materialism and look at it in depth later on. Now, dualism comes in different varieties, two of which have been especially influential historically. First, there is substance dualism, which holds that body and soul are two radically different substances or independently existing entities, and that a human being is a kind of mash-up of these two distinct entities. In ancient philosophy, this view is associated with Plato, and in modern philosophy it is associated with Descartes. We’ll be looking at it in some detail later on.

There is another and very different version of dualism associated with the ancient philosopher Aristotle and his follower Thomas Aquinas (who came around long after Aristotle, in the Middle Ages). On this view, a human being is just one object rather than two, even if not every aspect of human nature is physical or material. Sometimes called hylomorphic dualism, it holds that soul and body are not two different entities, but rather two aspects of one entity. In particular, the soul is the form of the body, and the body is the matter that takes on that form. (The word “hylomorphic” comes from the Greek words for matter and form.)

Plato Aristotle Aquinas Descartes

(429 - 347 B.C.) (384 - 322 B.C.) (1225 - 1274) (1596 - 1650)

Well, what does all that mean? And what are its implications? One of the implications is that for Aristotle and Aquinas, even though the soul is not a physical object, the body is still its natural home, as it were. The body is not a kind of “prison” from which the soul should seek to escape (as Plato thought it was). Nevertheless, Aristotle and Aquinas think they can prove that human beings are not entirely physical, and Aquinas thinks he can prove that the soul can even survive the death of the body (even if it survives only as an incomplete human being – our completion after death requiring a resurrection of the body). But why did they think all this?

As we’ll see, they give philosophical arguments for these claims. They don’t think that we need to rely on scripture or divine revelation or the like to know them, but can establish them by pure reason. However, to understand Aristotle’s and Aquinas’s views about soul and body, we need to understand their more general metaphysical picture of the world – in particular, their views about how the physical world in general works.

But to understand that, we first need to understand in turn a group of thinkers that Aristotle was reacting to – a group known as the Pre-Socratics, who were the first philosophers and first scientists in the Western tradition. For Aristotle hammered out his views about how physical reality in general works by explaining where he thought these earlier thinkers went wrong. We’ll come back to Aristotle himself, then, next time. For today, let’s take a brief tour of the thought of some of these founders of Western philosophy.

Cosmos vs. chaos

The Pre-Socratic tradition began in the 6th century B.C. in ancient Greece. Naturally, these thinkers are called “Pre-Socratic” because most of them were around before Socrates (though some were actually contemporaries of his). Socrates, as you may know, was the teacher of Plato, who was in turn the teacher of Aristotle. There’s a lot we could say about the Pre-Socratics, but we’ll focus on the main themes that are relevant to understanding Aristotle.

The Pre-Socratics noted that, at least on the surface, the world can often seem to be a chaos , devoid of any rhyme or reason, any rationality or order. There are two respects in which this is the case. First, the world is constantly changing – each season gives way to another, empires rise and fall, animals are born, mature, live, and die, and so on. Second, there is a bewildering multiplicity to the things that exist – tables and chairs, rocks and trees, dogs and cats, sun and sky, and on and on. It can seem that nothing is stable and nothing ties everything together.

And yet on a deeper analysis, the world always turns out really to be a cosmos rather than a chaos – that is to say, it is an orderly universe governed by law. Yes, things constantly change, but according to regular and predictable patterns that we can identify. There is in this way a deeper level of permanence underlying change. Yes, there are multiple things in the world, but they always turn out to fall into classes or categories with predictable properties and ways of behaving that we can study. There is in this way a deeper level of unity underlying multiplicity.

The Pre-Socratics all wanted to know exactly what it is that explains why the world exhibits the permanence and unity it has, why it is a cosmos rather than a chaos. They proposed different theories to account for this.

Why this and not chaos?

Thales and Anaximander

The first thinker to propose an answer – thus the first of the Pre-Socratics, and the first philosopher and first scientist in the Western tradition – was Thales of Miletus. His view was that the reason the world exhibits the stability and unity that it does is that everything in it is made of the same basic material stuff: water (of all things!)

This sounds pretty odd to us today, but we can give Thales a break because he was just getting the whole project of philosophy and science off the ground. And it’s not as silly a theory as it might seem when you consider it carefully. It’s obvious enough from everyday experience that matter can take on different forms, and different kinds of matter also obviously have certain features in common. If you extrapolate from this that there might be some one kind of matter underlying everything, it’s going to have to be a kind of matter that can take on many different forms. And of course, water can do that – it can be in a liquid form, a mist, a more ethereal gas, slush or snow, and solid ice. Thales seems to have extrapolated from this that maybe everything else is just water in some yet different form.

Seriously, Thales?

Well, he was wrong, but what makes him important is that at least he got the discussion going. Thales began the search for an explanatory unifying principle of reality that later Pre-Socratics – and indeed all of philosophy and science since – have carried forward.

An important advance was made by Anaximander, who saw that in modeling this ultimate source of order, we have to go beyond the material things of everyday experience. Whatever the ultimate source of reality is cannot be just one particular kind of stuff alongside the others (the way water is) but must be something more fundamental. Anaximander called it the apeiron , a Greek word which can be translated “boundless” or “unlimited.”

The idea is that if there is a source of all things – of hot things and cold, liquid things and dry things, large and small things, water and earth and air and fire – then it cannot itself be limited or bounded to being any one of these things rather than the others, but must be beyond all of them. Anaximander also argued that it had to be something that never comes into being or passes away, because otherwise there would be something beyond it which is the true ultimate cause (either to bring it into existence, or to knock it out of existence). So, he thinks of the apeiron as being something everlasting, infinite, and divine.

Heraclitus

The next three thinkers we want to say a bit about are important because they represent opposite extreme views on the question of the relationship between change versus permanence and multiplicity versus unity. First up is Heraclitus, who went about as far as one could go in the direction of emphasizing change and multiplicity without quite denying permanence and unity.

Heraclitus liked to sum up his views in aphorisms or pithy sayings, one of which was: “You can never step in the same river twice.” If a river is just the water that makes it up, then since the water is always changing, the river is always changing. Hence when you put your foot in the river, take it out, and put it back in again, there is different water there and thus a different river. The idea that it is the same river persisting over time is an illusion – so Heraclitus claimed.

Now, Heraclitus thought this was true of everything. For example, he would say that since your body is constantly losing old cells and gaining new ones, and your mind constantly jumps from one thought or experience to another, there is no stable and persisting you or self over time. There is only the illusion of stability. In reality, everything is constantly changing or in flux.

Heraclitus trying not to change

In Heraclitus’s view, the appearance of order and stability arises because of the principle of the harmony of opposites, which he illustrated with examples like a bow (as in a bow and arrow). A bow is made up of the wooden frame of the bow, and a string. Left to itself, the bow would straighten itself out, and left to itself, the string would lie there limp. But neither will let the other do what it “wants” to do. The frame keeps the string tight, and the string keeps the frame curved. They are in tension or opposition, but this struggle generates a kind of harmony insofar as out of it a useful instrument arises – something you can fire arrows with.

In Heraclitus’s view, all the order in the world arises because of this principle – it arises out of conflict or struggle between opposing forces. In this way, he thought of cosmos as something which, in a sense, arises precisely out of chaos.

Parmenides

Parmenides of Elea and his student Zeno go to the opposite extreme. They denied the existence of change and multiplicity, and held that only permanence and unity are real. What does that mean, exactly, and why did they think it? Their views are very strange, though also very interesting. They are difficult to explain briefly, but let’s give it a shot, starting with Parmenides. He argued that, though our senses tell us that change occurs all the time, this is an illusion, because logical reasoning shows us that change cannot occur.

Parmenides holds that change would involve being arising from non-being, or reality arising from non-reality, and that this is impossible. Hence, suppose you melt a plastic ball in a microwave oven. That would be an example of change – from the ball’s being solid and round to its being flat and squishy – and Parmenides holds that that means that the flatness and squishiness of the ball would go from non-being to being, from non-existence to existence. But non-being or non-existence is just nothing, and from nothing nothing can come. So, change really involves something coming from nothing, and that makes no sense. Thus, Parmenides concludes, change must be an illusion!

Young Parmenides

So too is multiplicity, he argues. He held that for there to be more than one thing in reality, there must be empty space between them. For example, if you consider a brick, it is one object rather than two because there is no empty space between the left and right sides of it. It is one continuous thing. If you break it in half, the reason there will then be two things is that there will in that case be empty space between the two halves.

But what is empty space? Parmenides says that it is just nothingness, the absence of anything. But nothingness, precisely because it is the absence of anything, is not itself a thing, not itself something that exists. So, there really is just no such thing as nothingness. But then, he concludes, there is no empty space, and thus nothing to separate off one object from another. So, the idea that there is more than one thing in reality is also an illusion!

Zeno

Zeno of Elea defends his teacher Parmenides’ weird conclusions with a series of famous and ingenious paradoxes. Let’s look at a couple of them. The dichotomy paradox is intended to support the claim that change, and in particular motion, is an illusion. It goes like this. Suppose a runner has to get from point A to point B. Nothing could be easier, right? But there’s a problem. For to get from A to B, he first has to get from A to the midpoint between A and B. But to do that, he first has to get from A to a quarter of the way between A and B. And to do that, he first has to get from A to an eighth of the way between A and B. And so on to infinity. So, he can never really reach B!

Ever smaller distances on the way to B A B

In fact, he can’t even get started. For, to get his foot even an inch off the ground, he first has to get it half an inch off; to do that, he first has to get it a quarter of an inch off; and so on ad infinitum. So, he cannot even begin the run! Of course, our senses tell us that such movement happens all the time, but Zeno’s claim is that logic shows that that is an illusion.

Zeno arguing with his wife

Then there is Zeno’s paradox of parts, which is intended to support Parmenides’ claim that multiplicity is also an illusion. Suppose there are many objects in the world. Then, Zeno says, either they have size or they have no size. Now, if they have no size, then nothing has size, because no matter how many things with no size you add together, they will never make up anything with size. And in that case, everything that exists will be the same size – namely, no size at all – which is absurd.

So, let’s imagine instead that things do have some size. Then we’ve got another problem. For Zeno argues that, if something has any size at all, then it can always be divided into parts of smaller size, and those parts can be divided into parts of yet smaller size, and so on to infinity. So, if things have size, then they have an infinite number of parts.

But wait: The more parts a thing has, the bigger it is. So, if things have an infinite number of parts, then they must have infinite size. And that means that if things have any size at all, they are all of the same size – namely, infinite size – which is also absurd. So, either way we go we are led to an absurd result. And what that means, Zeno says, is that the idea that there are different objects in the world leads to absurdity. So we should reject that idea. It is an illusion to think that there are multiple things in reality!

Needless to say, these are weird ideas! But they raise important puzzles about the nature of change and the nature of multiplicity, and about when we should trust abstract rational arguments over sensory experience. We’ll see that Aristotle aims to explain these things while avoiding the bizarre conclusions that Heraclitus, Parmenides, and Zeno were led into.

Here’s an optional series of YouTube videos on the Pre-Socratics, which you might find helpful:

Introduction to the Pre-Socratics:

https://www.youtube.com/watch?v=ZkMAx04jDx0&list=PLAYxecbGotUzdE4F5IMBgxN2o-biiRjGi