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Aristotle
Philosophy & Faith with Father Francis Selman ♦
"Aristotle, who lived in the 4th century BC, from 384 to 322, was a pupil of Plato but a man of very different outlook. No doubt he inherited his scientific interests from his father, who was court physician to King Philip of Macedon. But Aristotle did not become a doctor, as his father wished; instead, at the age of 17, he decided to go to Athens to study philosophy under Plato. The real world for Aristotle was not the world of Ideas but this visible, changing world, the world of nature, especially of living things, the world of things, which natural science observes and studies. Aristotle attacked Plato's theory of Ideas with many arguments. For instance, he argued that the real Horse could not be an immaterial Idea or Form, as Plato thought, when the nature of a horse includes having a body. Aristotle also pointed out that the cause of something being a horse is not a separate Form but two other horses who produce a new animal with the same form as themselves. Thus Aristotle did not think that the Forms actually exist on their own, independently, but only in the things of which they are the form. Thus the Horse Form does not exist in another world of Ideas or Forms but only in real, living horses in the visible world.
As Aristotle was interested in the world of nature, he was interested in motion and in the coming into and going out of existence of things. The motion of things and coming into and going out of existence of things. The motion of things and coming into and going out of existence involve change. Aristotle thought that all change requires a cause, because when a thing changes it actually becomes something that was at first only potential. To take an example: an acorn is potentially an oak tree; when it turns into a tree, a new tree has come into existence, and there are causes of an acorn and its growing into a tree. With this important distinction between potential and actual Aristotle was able to overcome Plato's problem about becoming and being. There is just one world of being: things are something and may be something else potentially which they are not yet or at the moment. The study of motion of course comes into physics, and Aristotle wrote a book called the Physics. Physics comes from the Greek word for nature, phusis: so 'physics' literally means the study of natural things.
I have already noted that motion, or change, has a cause. Cause has now come to mean almost exclusively an efficient cause, what sets something in motion by its action, as water causes rust by the action of oxygen on metals. But Aristotle distinguishes four kinds of cause in his Physics, Book 1, for he notes that a thing is made out of something into something by something for something, which is its end or purpose. For example, a box is made out of wood (its material cause) and this wood into something with the form of a box (its formal cause) by an agent (a carpenter, an efficient cause) for a purpose, say, to hold shoes or buttons. A cause of something is also an explanation of it. It is now common to decry the concept of cause and suppose that we cannot know causes but only state 'statistical probabilities', since atomic physics in the 20th century has taught us about the unpredictable movement of electrons and other particles. But causes explains why the world is an ordered one, as it clearly is: indeed natural science arose as the search for the causes of things in nature. There clearly is a cause of a train leaving a station (this does not just happen at random), and indeed of a locomotive and carriages existing at all. Moreover, a train does not just start off into nowhere: it is given a direction or end.
Aristotle did not just note that things come into existence: he also asked what it is for something to be an existent thing. This is the question of being, with which metaphysics deals. Metaphysics literally means what comes after physics or lies beyond physics, that is, beyond what naural science studies. Aristotle noted that things either exist by themselves or in other things. For example, colours and surfaces are never found by themselves: they are the colours or surfaces of things, so they only exist in other things. Clearly the primary things are things which exist by themselves, for nothing can exist in another unless there first are things which exist on their own. Aristotle called these substances. Thus substances, not Plato's Forms or Ideas, were the primary real things for Aristotle. Aristotle gave various meanings to the word substance, which can be found in Book 7 of the Metaphysics. One was that substance is the subject of change. This is rather like our use of the word 'substance' for some matter: for example, potassium is a substance. Another meaning is that a substance is an individual thing. Aristotle thought that living things, like animals and insects, were substances. But we could also say that a statue or any artifact is a substance in the sense of an individual thing. A material substance consists of matter and form for Aristotle. He thought that matter never exists just on its own, but only exists with some form or other, at the most basic level with the form of one of the elements: barium has a different form from magnesium. Thus an object never consisted just of its material constituents alone for Aristotle; it also had a form as a whole. Science, physics and chemistry, analyses material objects: they have made us forget that things are not just a mass of atoms or particles but have a form as a whole.
A notable feature of Aristotle's natural science, which distinguishes him sharply from many of our contemporaries, is that he thought that things in nature have an end. The end of a plant or animal, for example, is to reach its perfect development. It is difficult to deny that many things in nature serve a purpose or end: Aristotle gives the example of leaves, to provide shade. To say that things have an end is quite contrary to thinking that the world has just come about by chance. He also thought that we have an end. The end of human beings, he says, is to act well, just as the end of a harpist is to play the harp well. In Aristotle's view, we act well when we act according to our nature, not contrary to it. Thus for us to act well is to act according to reason, because we have rational nature. To act according to reason is what we mean by virtue. He discusses the virtues, especially justice, courage, prudence and temperance, in his book the Nicomachean Ethics. He begins this book by observing that we almost always act for an end: I clean my teeth to keep my teeth healthy, I put on a pullover to keep warm, I take a bus to go to the chemist, and so on. But he also asks whether there is some end to which all our actions and other ends are directed. And he thinks there is: it is happiness. No one desires to be unhappy. Happiness took two forms for Aristotle: the first is to flourish by taking a full part in the life of the city state, especially by the practice of the social virtues. But in Book 10 of the Ethics, he says that activity makes us most happy which is most like God's activity. This is contemplation. The connection between the two is that the life of virtue disposes us for contemplation."