The Most Important and Controversial Attribute of God: Divine Simplicity

The most important and controversial attribute of God is the doctrine of divine simplicity. While it has always been important, it has not always been controversial. It enjoyed almost universal acceptance from the time of Augustine until recent times. So what is it? It is the doctrine that there are no parts in the divine essence. There is no composition of anything. God is not made up of different aspects or parts of his being. It is best articulated in the work of Thomas Aquinas, especially his Summa Theologiae and his Summa Contra Gentiles. The doctrine is rooted in the metaphysics of Aristotle, and the Neo-Platonism of Augustine.

Metaphysical Foundations

While Plato held that the Forms (and God) are not divisible in any way, the notion of simplicity is better articulated in the works of Aristotle and later applied to Christian theology via Thomas Aquinas. Thus, we shall begin with what Aristotle has to say. In doing this, I will briefly make some distinctions regarding aspects of composed beings, that is, beings that are in the sensible world (the world that can be sensed).

Substance and Accidents

In his work, Categories, Aristotle makes both a logical and metaphysical distinction between ‘substance’ and ‘accident’. A substance refers to something that “stands under” other things. It is that in which a thing’s accidents (characteristics) exist. When Aristotle uses the word ‘accident’, he is referring to things like place, quantity, quality, time, relation, etc. The “categories” are the substance plus nine accidents, like those just mentioned. Accidents are predicated of a substance. For example, we can say a beagle has brown hair. The “brownness” of the hair is a quality, or accident, in the dog. But there must be something that “contains” the brown-ness. That is the substance—the dog. Taken as a whole, the substance is the individual. To use Aristotle’s own examples, the man as a whole is a substance; the horse as a whole is a substance. So, for Aristotle (and Aquinas), there is a logical and metaphysical distinction in things regarding their substance and accidents.

Act and Potency

Another distinction for Aristotle, and later Aquinas, is the distinction between act and potency.  To be in ‘act’ is to have existence in the objective, extra-mental world. We can talk about the difference between Charlie Brown’s dog, Snoopy, and a real beagle that is something you can actually pet. Snoopy does not have the same kind of existence as a real beagle. Snoopy is a being in the mind that can be represented in various ways (cartoons, toys, etc.). But actual beagles have a more real way of existing. Anything that exists outside the mind, for Aristotle, is in act. You and I are in act. The trees outside are in act, etc.

At the same time, beings in the sensible world can change. I, for example, can change from sitting to standing. Wood can be turned into furniture or firewood. Plants change in size and shape. In order for things to be able to change, they must have the potential to change. In Aristotelian language this is called potency (power). I have the potency to change from sitting to standing. Wood has the potency to be furniture or firewood, and so on.

The only way a change can take place is if there is a being that is in act which has the potency to undergo a change, and that being must retain its overall identity, or it will simply be the annihilation of one being and the creation of another. (Creation is not a change, it is the introduction of new being.) Thus, changing (material) beings have both act and potency. We can say they are composed, metaphysically, of act and potency. It is important to note that act and potency are not beings in themselves, but are rather principles of being. For example, potency is not a thing in itself: literally it is no-thing, or nothing. Sensible things, therefore, are composed of act and potency.

Form and Matter

Physical things are also composed of form and matter. Humans have a nature; they have a material and an immaterial aspect (body and soul). We can think of form as the aspect of a being that makes it what it is. For Aristotle, this is called he formal cause, i.e. that which makes something what it is. For example, the form of a beagle makes it a beagle. The form of a human makes it a human. Being physical does not make a being be what it is. Humans and squirrels are both physical, so it is not the physicality that makes them different. It is their nature. This nature is what is signified by the word ‘form’. Humans have a human form, and squirrels have a squirrel form. The form is the more universal aspect that all humans have in common; they don’t share their matter. Matter makes each human different—it individuates us all. It is the form that informs matter to make a being what it is. But again, form by itself is not a complete being for sensible things. And the word ‘matter’ has a wider use than just something being material in the ordinary sense of the word. Matter is in potency to form. Form actuates matter. (Thus, matter before it is physical, and as a principle of metaphysics, is called prime matter. Prime matter is not a thing, but a metaphysical principle that signifies what things are actuated from.) In this sense, matter is the potency, and form is the act. Neither matter nor form exist on its own for sensible beings. The form/matter composite makes a being be what it is. For example, a human is composed of a soul and a body. For Aristotle (contra Descartes), these are not complete substances in themselves. The individual taken in itself as a composed being, of form and matter, is the individual. For a human, the soul is the form. (As the substantial formI, the soul makes the individual what it is.) The body is the material part, which makes one human different from another. The essence of a human then, is to be a composite of form and matter, but it is the form that gives the matter its nature. Sensible things, then, are composed also of form and matter.

Essence and Existence

Another way sensible things, and actually non-sensible things, such as angels, are composed is by essence and existence. By ‘essence’ is meant what a thing is, or its nature. Existence means (in the Thomistic sense of act, which is somewhat different from Aristotle) the “act of being” in the real, objective world. We can talk about the essence of unicorns or leprechauns, for example, without maintaining that they actually exist apart from our minds. We can describe them, talk about them, and agree with others about what they are. But most people do not assert their actual existence. So, they can have an essence (what we mean by the term ‘unicorn’, for instance), without having existence. Thus, their essence does not guarantee their existence. So, then there is a distinction between their essence and existence. (In his work An Elementary Christian Metaphysics, Joseph Owens explains this distinction in more detail than I can do here. He argues that the distinction only follows when we have demonstrated that a necessary being exists as the efficient cause of all other beings, requiring them to receive being from him. Because they can’t account for their own being, there must be a distinction between essence and existence.) It is often said that the difference between essence and existence is between what a thing is (its essence) and whether it is (its existence). This is another way Aristotle and Aquinas believed that things are composed.

Divine Simplicity

While the above distinctions apply to creatures, according to the doctrine of divine simplicity, they do not apply to God. One of the easiest ways to grasp this, in my opinion, is to hear the words of the First Way given by Thomas Aquinas for demonstrating God’s existence. I’ll summarize it for the sake of brevity. It is clear to all (well, most) that in the sensible world things change (he uses the word ‘motion’ which just means change). But, as already noted, in order for a thing to change, it must be composed of act and potency. Things that are composed, must be composed by something that already exists (or is in act). A thing cannot compose itself (bring itself into being), so it must be composed by another. Since the latter is true, the being that brought it into existence (composed it) must also either be composed by something else if it is composed. But this cannot go on forever to infinity, since it would not explain how the series of changed (moved) things was put into motion. So, there must be a being that is not composed; that is, it does not have different metaphysical parts. Since potency is in reality no-thing, and act is existence, this being would simply be Pure Act. It would not be composed of potency, and thus not require a composer.

If he is indeed Pure Act, then there is no division or composition in him. He therefore is not composed of form and matter, since the composition of those aspects of being would first require the potency for their composition. God also cannot be composed of form and matter as matter is a potency, and if God is Pure Act, he can have no potency in his being. The same holds true for substance and accidents. There are no accidents in God since they would somehow qualify the divine essence. With a being of Pure Act, there is no room for qualification. Nothing inheres in the divine essence of Pure Act. If accidents did inhere in the divine essence, there would be distinction in him, which is impossible if he is Pure Act. Such an inherence would also introduce the potency for composition and be a denial of Pure Act. He also has no distinction between his essence and his existence. If there were, then they too would require composing. For God, existence is an essence. In short, according to divine simplicity, there is no composition in God in any way. He is infinite, unlimited existence. If he were composed, he would need a composer, and thus not be God.

Put another way, simplicity means that when we talk about God has having different attributes (characteristics, not accidents or properties, since the latter entail composition, while the former is just different ways of describing one being), those attributes are not really distinct from each other in the divine essence. A typical objection to divine simplicity is that goodness, justice, and wisdom, for example are not the same things. But in God, according to simplicity, they are the same thing. Since this seems to result in a problem (justice is not the same as wisdom), simplicity must be false. It is true that when we use terms like ‘justice’, ‘wisdom’, and ‘power’, we don’t have the same thing in our minds. We are picking out different aspects/characteristics/attributes of God. This is because as material, composed beings, we have no other way to talk about things. All of our knowledge is based in the sensible world, which is composed. We thus know that God is simple by starting with composed beings, and denying certain (inferior) ways of being to a being that is perfect. So, when we say that God is x, y, and z, we don’t mean the same thing definitionally. However, in God, they are all the same—if simplicity is true. For a fuller treatment on this issue, see question 13 article 4 of the ST, and chapter 31 of the SCT.

I am admittedly flying through both the metaphysical foundation for this doctrine, as well as the doctrine itself. In later posts, we will look at some objections to divine simplicity. For now, I hope this clarifies somewhat what the doctrine is, and why it was affirmed almost universally for over a millennium—until recent times.