While Plato had his head turned towards the ideal world of the Forms, Aristotle had his very much turned in the opposite direction, toward the world of matter and the everyday. Aristotle was a prolific writer and his studies ranged across an extraordinary number of diverse subjects. His interest in biology alone and the dissections and detailed accounts of animal physiology he carried out and wrote about, easily give him right to the title, the first scientist.
Pinning down exactly what metaphysics is and, just as importantly, what it meant to Aristotle requires a little bit of explanation because Aristotle’s Metaphysics contains a number of treatises that seem to cover a range of disparate topics, including topics which also feature in other works of his. In addition, it is widely believed that the Metaphysics got its name from a cataloguer who, merely noting that Aristotle wrote about these topics after he wrote the Physics, gave them the collective heading meta (meaning ‘after’) physics.
Aristotle never actually uses the term itself although he does refer to “First Philosophy” which he defines as the investigation of Being as Being, and which we may paraphrase as the study of existence. Since then, metaphysics has come to mean anything which ‘transcends’ physics and, given the modern dominance of science (and physics in particular), has earned for itself a wishy-washy, pseudo-mystical reputation. This need not be the case though. With that said, I will treat under the heading of metaphysics the following subjects: being, form and matter, soul and mind, God, and causality.
‘Being’ for Plato was firmly located in the Forms. Aristotle rejected these other-worldly entities of his master. He introduced the terms ‘substance’ and ‘universal’ which he used to refer to individual things and universal terms, respectively. Universals can be predicated of many subjects (substances), while substances themselves are never predicated. By way of example, in the sentence, ‘Socrates is a man’, ‘Socrates’ is the substance whereas ‘man’ is the universal term.
According to this, a universal term should never take the name of a substance, because they refer to completely different categories of things. So, since ‘love’ is a universal term denoting an emotional state, it cannot ever be a particular substance as well. However, in Plato’s theory of the Forms, the Form of “Love” really existed somewhere as a substance and for those who were able to perceive this realm, it could appear to them like a substance. In this way, Aristotle rejects Plato’s notion that for every physical ‘thing’, a correlative Form exists.
Aristotle also coined another related term here, ‘essence’, which denoted the “very nature” of a substance. It was that property (or properties) which a thing could not lose without ceasing to be itself.
Aristotle also used these terms to attempt to understand change, which was something of a problem for earlier philosophers. In short, the notions of ‘substance’ and ‘essence’ gave Aristotle something to anchor change in while the change itself can be thought of as variation in accidents or qualities (such as colour, shape, size, movement, etc.) which do not exist on their own but only in relation to a deeper, more permanent core ‘substance’.
In making the case for the above terms, Aristotle was very much bringing the notion of existence back from where Plato had banished it to an ethereal realm, and holding it up before our eyes, in the here and now. Unfortunately, in the Middle Ages, when Christians were desperately trying to square Aristotle with their supernatural beliefs, these terms acquired a pseudo-mystical importance which resulted in much confused thinking. It is significant to note that even Descartes and Spinoza, philosophers traditionally considered as belonging to the modern period, both thought in the terms dictated by Aristotle almost two millennia prior.
Form and Matter
The idea of change also led to another insight for Aristotle when he wondered what it was about things that allowed for change to take place. He identified two principles at work here; one he called the principle of actuality and the other, the principle of potentiality, or simply act and potency. The basic idea here is that act imparts to potency all of the concrete determinations found in a thing.
The principles of act and potency for physical things are form and matter, respectively. In other words, form (as act) gives shape to matter (as potency) and determines its actual state, or essence. This is called the hylomorphic doctrine; hyle meaning ‘matter’ and morphe meaning ‘form.’ Matter which has more form is considered to be more ‘actual’; hence pure matter without form is pure potential.
I should note that ‘form’ here doesn’t merely refer to the physical shape of the matter in question; it seems to have a more profound meaning for Aristotle. Bertrand Russell suggests that it is what lets us see a ‘thing’ as a unified whole. A cell phone, for example, can be seen as a collection of atoms, a collection of molecules or a collection of parts, but it can also be seen as a whole thing; a phone.
Soul and Mind
The principles of act (form) and potency (matter) for living beings are soul and body. Aristotle’s philosophy here is again, quite different from his teacher’s. Plato thought that the ‘real’ human was a separate soul which was, in a sense, ‘trapped’ in a physical body. Aristotle, in explaining the human being with reference to form and matter, essentially dissolves the distinction between soul and body. They can no longer be thought of as two different things and the idea of one of them existing without the other becomes nonsensical.
This naturally means that Aristotle didn’t believe in any kind of existence after death. When the body dies, the soul dies with it. This isn’t the whole story, however. Aristotle maintained that the soul is made up of two parts; one rational, one irrational. The irrational part is further divided into two: the vegetative, which occurs in all living things, and the appetitive, which exists only in animals. The rational part (or ‘mind’), Aristotle associates with the divine and considers it to be something ‘higher’ and altogether separate from the other (irrational) parts of the soul. Considering that it bears no relation to the senses, it will live on after the body dies. The one catch is that the immortality of mind is therefore something impersonal. We, as ourselves, won’t live forever but our minds, as a part of the divine, will.
Aristotle was not particularly religious and had little time for notions of a personal deity the likes of which a post-Christian thinker would recognise. In hylomorphic terms, Aristotle’s God is pure actuality and pure thought, which means He is incapable of change.
The central argument for God was the so-called Unmoved Mover. Aristotle held that there were three kinds of substance; the first class which includes plants and animals, the second includes the heavenly bodies (which do not undergo any change, except motion), the third is the rational soul and God. Earthly motion could be explained by reference to the heavenly bodies (e.g. the heat from the sun stirs things up here on Earth) but how could one explain the motion of the heavenly bodies themselves?
If you are going to posit a God, it would surely make sense to invoke Him here, but then we would have to explain what moved God, and so on, leading to an infinite regress. This is where Aristotle postulated that God is the Unmoved Mover, Himself stationary and unchanged while at the same time acting as the source of movement in the heavenly bodies. The way Aristotle resolves this is to theorise that the heavenly bodies are moved to action by admiration and desire of God. This works in the same way that a piece of cake can inspire movement in someone who loves cake. I see the cake and go over to get a closer look (or a quick taste), so even though the cake hasn’t actually done anything, in a sense, it has aroused motion in me. God does the same thing for the heavenly bodies.
Of course, this isn’t much of a God, as a Christian might think of Him. He certainly doesn’t listen to human prayers, much less grant them. In fact, He doesn’t actually appear able to do anything; we have already seen that He is pure actuality or pure thought and therefore incapable of change. However, there is one thing that God can, in some sense, do, according to Aristotle. Since God is thought and since the most perfect form of thought is intellectual contemplation, it follows that God spends eternity in contemplation. And what does He contemplate? Why, the only object suitable for divine contemplation; Himself.
Thinking about change also led Aristotle to wonder about the causes behind change, of which he identified four; material, formal, efficient and final. The ‘material’ is the substance that actually undergoes the change, the ‘formal’ is the completed shape or form the change results in, the ‘efficient’ is what impels the change, and the ‘final’ is the end towards which the change is aimed. If we consider a statue, the material cause is the marble from which the statue is to be sculpted. The formal cause is the shape which the marble takes once the sculptor has finished; the ‘unity’ of the finished product; a person, an animal, etc. The efficient cause is the sculptor herself and the final cause is the production of a work of art.
In modern parlance, we only recognise the efficient cause. However, it is worth highlighting Aristotle’s final cause because this is how he rectifies what he saw as a deficiency in the physical theories of Democritus, Anaxagoras and Empedocles; namely, the absence of any teleological purpose to nature. The notion of a final cause bestows purpose on everything and this is central to Aristotle’s philosophy.
Perhaps the most enduring contribution to be found in all of Aristotle’s works was that which came in the field of logic. He formalised a lot of key ideas in the subject and even though his system of logic was incomplete his reputation was such that everyone assumed it to be complete until well into the nineteenth century. Among some of the terms he identified were the univocal (a word used in two statements holding the same meaning in both, i.e. ‘animals are creatures’ and ‘man is an animal’), equivocal (the same word used in two statements with different meanings, i.e. ‘on the bank of the river’ and ‘get some money from the bank’), the particular and the universal.
One of the most powerful weapons in the logician’s arsenal is the syllogism which is basically a deductive argument made up of a major premise and a minor premise which together lead to an inevitable conclusion. Aristotle outlined and organised into categories the many different forms syllogisms may take.
Unfortunately, as mentioned, Aristotle’s system of logic (based entirely on the deductive syllogism) was incomplete in at least three ways: first, it didn’t account for deductions which relied on propositional logic, where variables stand for whole propositions; second, it couldn’t express relationships between two or more objects; and third, it ignored inductive logic, which sacrifices certainty for the benefit of adding new knowledge.
Interestingly enough, the first problem was found and fixed by the Stoics and the second treated by Galen, a second century doctor, but the dominance of Aristotle was so complete that their findings were by and large ignored.
Aristotle’s ethical theory is outlined in The Nicomachean Ethics. It is worth mentioning that ‘ethics’ in Ancient Greece was a much broader concept than we typically understand by the word today. It was more about investigating what makes an ‘excellent’ or ‘well-lived’ life, rather than a list of ‘good’ and ‘bad’ actions.
Aristotle rejects Plato’s universal Form of the Good, arguing that things are called ‘good’ in many different senses (a good book, a good person, a good time for studying, etc.) and it doesn’t make sense that there could be a single, universal ‘Form’ to accommodate all of them.
He starts his ethical investigation by trying to identify the supreme good at which every act ultimately aims. This good must be something we desire for itself, not merely as a means for getting something else. This supreme good turns out to be Eudaimonia, a word usually translated as ‘happiness’ but which has a much deeper meaning than the temporary, fleeting emotional ‘high’ we think of when we hear the word. Next, Aristotle must discern what happiness (whenever I use the word ‘happiness’ I mean the richer sense of Eudaimonia) consists of. He does this by investigating the function of humans which turns out to be performing actions in accordance with reason; hence the function of a ‘good’ human is to perform actions in accordance with reason ‘well’. Since performing well or ‘excellently’ (arete) is the same as performing in accordance with virtue (arete), this is the supreme good for humans; happiness derived from performing actions in accordance with virtue.
Aristotle distinguishes between two kinds of virtue; moral and intellectual. The former is acquired by habit and is therefore not innate, while the latter is instilled by instruction and therefore requires time and experience. Because both of these require instruction and good role models to acquire, Aristotle makes the interesting claim that ethics is therefore a political concern. The reason for this is that it will ultimately be the state that is responsible for creating the environment (laws, educational system, etc.) in which people learn these virtues.
Aristotle also introduces his doctrine of the golden mean, which holds that virtue always occupies the mean between two extremes, one of excess, one of deficiency, both of which are vices. For example, a deficiency of courage leads to cowardice while an excess leads to foolhardiness. Courage can only be found between these extremes.
Finally, Aristotle announces that since happiness is the ultimate good, surely the virtue we are talking of here must be the highest virtue. As we saw in the section on ‘God’ above, the highest virtue is intellectual contemplation. This means that the happiest life is the life based on intellect, that is to say, one engaged in contemplation. He even goes so far as to say not only is contemplation happiness, but the more one contemplates the happier one is. Aristotle sees contemplation as something divine and when we undertake it we are partaking in the divine.
This is something of an odd move because it basically disregards virtually everything that preceded it. What happened to the moral virtues Aristotle spent so long dissecting and analysing? Living well according the ‘moral’ virtues turns out to be a secondary form of happiness because it is human, as opposed to divine.
Aristotle believed that matter was composed, not of Democritus’ atoms, but of four qualities (hot, cold, moist, dry) that ended up combining in pairs to yield Empedocles’ four elements: fire (hot and dry), water (cold and moist), earth (cold and dry) and air (hot and moist). These elements could all combine in different ways to form the different objects in the physical world. Moreover, this formulation of matter gave each of Aristotle’s elements the potential to turn into any other through a shuffling around of the qualities; e.g. if water (cold and moist) was heated, it would become hot and moist (air).
Each element had its own natural motion. Earth and water would naturally travel downwards towards the centre of the universe (the middle of the planet) while air and fire would rise upwards. This also explained heaviness and lightness: heavy things were those with more water and earth and light things were predominated by fire and air.
Everything also had a naturally preferred motion. Earthly elements moved in straight lines whereas the heavenly bodies (which were perfect and unchanging, except for motion) preferred uniform circular motion. To explain this, Aristotle invented a different element called ‘quintessence’ or ‘aether’, which the heavenly bodies were comprised of.
He also postulated an ‘outermost heaven’ which was a gigantic sphere in which the stars were embedded. This sphere rotated because of its desire for the Unmoved Mover (see the ‘God’ section above) and it mechanically transmitted that motion to smaller spheres within it which carried all of the other heavenly bodies, the whole thing working like clockwork, wound up by a form of desire for the Unmoved Mover.