One might well ask why it is important to hold to the view that God is simple.  Indeed, before one asks this question, one might ask a clarifying question: What in the world does it even mean to say that God is simple?  The notion of simplicity is confusing because of how it is commonly understood in contemporary parlance.  When I say that a concept is simple, I likely mean that it is not hard to understand.  This is emphatically not what was and is meant by philosophers and theologians who wish to say of God that He is simple. 

What is meant then by saying that God is a simple God?  Well, at the risk of oversimplification, it means that God is not a divided being; he is a single unified entity.  To many readers perhaps, this definition is as clear as mud.  A little unpacking will hopefully help. 

A Unified God

When it is said that God is not divided, what is meant is that He as He is in Himself is incapable of being compartmentalized.  When I speak of my cat, I can pick out distinctive features of my cat that are of interest to me and other cat lovers: his grey and white fur, his short and fat tail, his whiskers, and so forth.  Now, all of these parts of my cat can be spoken of separately because it is not essential to my cat’s being what he is that he have the things I have mentioned.  There are imaginable circumstances in which my cat could have a long and skinny tail and other imaginable circumstances in which my cat simply does not exist at all.  Now, it is of course true that when we speak of God, we can distinguish different characteristics from one another: God’s wrath, love, justice, mercy, and grace are not identical things when we think and speak of them.  However, God is not a little love here and a little justice there; God is equally and always powerful, just, merciful, and so on.  The doctrine of simplicity allows us to see God as a being who is harmonious with Himself since He never changes and is always just and good. 

When we say that God is simple, we mean that He is so uniquely one that His characteristics, i.e., His being eternal, unchangeable, and loving are not incidental to Him: without these characteristics, God would cease to be God.  Most theists have held that God not only exists but that it is impossible that He should not exist given the sort of being He is. 

To sum up, the idea that God is simple safeguards this exalted view of God.  If God can be divided into parts, then two features of His being God would be impossible, namely, His being eternal and omnipresent.

The traditional view of God, that which was held by Augustine, Anselm, Aquinas, and by Reformation Protestantism, taught that God is timeless.  This means that God does not exist from one moment to the next in which He performs some actions in the past, sees their results in the present, and anticipates what He will do in the future.  Every moment of past, present, and future time is equally present to God.  This way of speaking about God refers to His eternality. 

Furthermore, the traditional view of God held that God is omnipresent.  Just as there is no moment of time God occupies in distinction from other moments of time, so there is no point in space that God occupies.  He is outside of space and time, or to use more contemporary terminology, He occupies no portion of space-time.[1]

The simplicity of God also makes it possible to make sense of the fact that God is spiritual.  If God were divided into parts, He would be able to be in only one place at a time.  Material bodies are by definition objects that have extension through space, each part of material bodies being somewhere in particular and not nowhere in general.  God’s simplicity ensures that He is spiritual and not material and therefore that He possesses both eternality and omnipresence, attributes or characteristics thought to be essential to God, characteristics without which He would indeed not be God. 

Why the Contemporary Rejection of Simplicity?

There are several reasons why the doctrine of simplicity is rejected by some contemporary philosophers.[2]  I will focus on just one key reason.  Many think that the doctrine of simplicity gives Christians a God who is impersonal, cannot respond to change, a God who is unmoved by the plight and suffering of His children.  Almost all Christians these days would recoil at the thought that God is not a person, but Brian Davies sees no reason why God’s not being a person poses a problem.[3]  Orthodox theology up to the end of the Middle Ages reserved the term “person” for the distinction between Father, Son, and Spirit in the Trinity, but the divine nature was never referred to as a person.  In fact, when we think of the word “person” in contemporary terms, we likely think of incredibly limited beings who occupy one place at a time, experience growth and decay, frequently are in error concerning the right course of action, and who change their minds unpredictably.[4]  Therefore, the reason why the doctrine of simplicity was held to for so many centuries was because the Christian church regarded it as the best way to preserve what needed to be said about God in order for Him to be conceived as a worthy object of worship.  While it is true of course that the Bible uses language implying that God changes His mind or reacts in love or anger and therefore involves Him in change as well as in time, the tradition of classical theism (the view discussed here) held that all such language is merely an aid to our puny understanding.  We human beings are incapable of relating to God as He is in Himself.  God is timeless; we are creatures who cannot think outside our past, present, and future existence.  God does not change in His purposes or promises or in His nature; we undergo change from birth to death; every moment, we are changing.  God occupies no particular point in space; we are limited to one place at a time by our physical makeup. 

Conclusion

God is a simple being.  He cannot be divided into parts.  Our speaking of God as having love or power or knowledge as separate characteristics is merely our way of conceiving of God but not according to what He is in Himself.  God is according to the doctrine of simplicity all of the things we ascribe to Him, and He is all of these things at once. 

There are many questions that have not been answered in our attempt to isolate the doctrine of simplicity from other theological considerations.  How can a simple God be triune?  How can a simple God be incarnated in Jesus Christ?  Theologians have of course tried to answer these questions.  Suffice it to say that while the doctrine of simplicity poses problems for god’s being triune and for the doctrine of the Incarnation, the problems have not seemed insoluble.  But according to the tradition of classical theism, if the doctrine of divine simplicity is false, then it might well have been the case that the Incarnation might not have occurred at all.  For the doctrine of simplicity affirms that God is eternal and unchangeable and that therefore His works are planned in an eternal and unchangeable way.  If God is not simple, then perhaps He might be capable of change and therefore, the Incarnation might not have been the stupendous event in history it is.  Indeed, if the doctrine of divine simplicity is in fact false, then according to the tradition of classic theism, God is no more a worthy object of worship than the most powerful mortal would be.  So while the doctrine may not have immediate practical consequences, it surely has long-term implications that a concerned theist cannot afford to give up.