The Five Ways and Deification

by David Russell Mosley, Ph.D.

Fr. Kimel has been hounding me for sometime (OK, maybe that’s not quite correct) to write a post for him here at Eclectic Orthodoxy. Sadly, all of my best ideas were going to my own blog and I was left bereft until I read a post by Fr. Kimel that began with a discussion of the Five Ways in Thomas’ Summa Theologiae. Here was an opportunity to dovetail with something Fr. Kimel has already written, but in a different way. So, today, I would like to discuss with you wonderful readers of Fr. Kimel’s blog the relationship between the Five Ways and deification.

I was first put onto the notion that there is a relationship between the Five Ways and deification by A. N. Williams in her excellent book The Ground of Union. There Williams writes:

The Five Ways thus establish both God’s aseity and his voluntary connectedness to all that exists. The Third and Fourth Ways, moreover, indicate that what God graciously shares with creation are those features of his own life that Aquinas has told and will tell us are most characteristic of divine nature: being, goodness, perfection. In seminal form, the Five Ways argue not only for God’s existence, but also the existence of a Thomistic doctrine of theosis. (p. 41)

For Williams, each of the Five Ways tells us, essentially, one of two things (perhaps sometimes both). On the one hand, God is qualitatively different from creation. He is not simply bigger and better than creation; he is utterly unique in relation to it. On the other hand, God shares his very uniqueness with creation. Put together, or so Williams argues, we see an argument for deification in Thomas Aquinas. Of course, however, we should not simply take her word for it, but investigate the question for ourselves and this is what I will humbly attempt in this post by looking at each of the Five Ways in turn.

The Five Ways, or Five Proofs for God’s Existence, come very early in the Summa Theologiae. This section can be found in ST Ia. 2, 3. It should be noted that the initial question Aquinas is answering in this section is whether or not God exists, not, whether or not the existence of God can be proven (not as we normally mean that today). That is, Aquinas is not so much interested in setting up a series of syllogisms that prove, beyond a shadow of a doubt that God exists. I mention this only because it comes up so often in debates surrounding apologetics. We must remember that the Summa was not written to convert atheists (not by itself, anyway) but to instruct.

The first of Five Ways is often called the argument from motion, though argument from change might be better. Aquinas argues that it is obvious that things move (and by move he does not simply mean locomotion, moving from one place to another, but also change, moving from one state to another, like moving from potentiality to actuality). Everything moves and everything that moves is put into motion by something outside of itself. Aquinas argues, however, that we cannot have an infinite regress. That is, we cannot say that there are an infinite number of movers going back into eternity. The reason there can’t is because if nothing starts the process then the process can never start. Think of it this way: consider the birth of an elephant. What made this elephant capable of being born is that its parents too were born, and so were their parents, and so were their parents’ parents, and so were their parents’ parents’ parents, and so on. However, if this went on into infinity then the baby elephant with which we began could never have been born, for there were no first elephants (or elephant like creatures) to serve as its greatest possible elephant ancestor. Evolutionary biology actually plays this out with the argument that all species derive from a common ancestor. There had to be a first something to crawl out of the primordial ooze to serve as the first parent to the rest of us. Similarly, God serves as the first mover, but in order to be first, he must, unlike everything else, be unmoved. Now, I’ve belabored the point here for this very reason, even the first speck to procreate in the primordial ooze came from something, it was moved, worked upon by outside forces. God is different. He is not worked upon by outside forces, he is unmoved and yet is the cause of all motion. God is qualitatively different from creation in the fact that he is not only the first mover in the series, but is himself unmoved (otherwise he could be first), that is, he is also outside of the series altogether. He is other than we are.

The Second Way is similar. Here God is described as the first, uncaused, efficient cause. I won’t go to the same pains to show why infinite regress cannot exist here as well. Rather what is necessary to understand is that this Way, like the previous, describes God as being intimately related to creation (he moves and causes it) but is also utterly distinct from creation. Traditionally, we would say that God is immanent and transcendent. The point Aquinas appears to be making is that it is God’s transcendence, his being utterly different from creation, that allows him to be immanent.

The Third Way solidifies for us that God is utterly distinct. He is the necessary being. That is, while we can imagine all sorts of things as not having existed and can thus conclude that they don’t need to exist, at one point didn’t exist, and will not always exist, in order for this to be true, there must be one who (or I suppose which) has always existed. That is, if we can imagine everything as not having existed, that means that one point nothing existed. And if nothing existed then there was nothing to bring everything into existence. Therefore, we must posit one who exists outside the possibility of not existing. This one would be utterly unique, totally different from everything else we know to exist since everything else is contingent and it is not. Not only is it not contingent, but it is the cause of all that exists. Aquinas writes, “Therefore we cannot but postulate the existence of some being having of itself its own necessity, and not receiving it from another, but rather causing in others their necessity” (ST Ia. 2, 3). God is not only the necessary being, but he is the cause of all other beings.

The Fourth Way argues for God’s existence based on the fact that God is the source of created beings’ perfections. It is often called the argument from gradation for in it Aquinas argues that we say things are more or less good, or useful, beautiful. The idea of gradation implies a standard. The example Aquinas uses is fire. We call one fire hot and another hotter. Aquinas writes, “Now the maximum in any genus is the cause of all in that genus; as fire, which is the maximum heat, is the cause of all hot things” (ST Ia. 2, 3). While we now know from physics that friction, and not fire per se, is the cause of heat, Aquinas point still stands. Friction, ultimate friction, is the cause of all other frictions and it is how we denote one friction hotter than another. Aquinas then argues that there must be a maximum for all perfections, that is all ultimates, and this includes being. There must be a being who isn’t, properly speaking, a being at all, but the being, the source of all being (and thus all truth, goodness, beauty, unity, etc.). This being is God. Up to this point, with one caveat to make for the Third Way, Aquinas has been telling us that God is the utterly distinct being. God is not like a creature in creation, rather he stands outside of creation as the utterly unique one. However, now, and because of the Third and Fourth Ways we can see this more evidently in the First and Second, this utterly distinct one is the source of all that exists and shares his uniqueness with his creatures. He is not only the Unmoved and Uncaused, but the First Mover and First Efficient Cause. Not only that, but he is the Necessary Being, necessary because without him, nothing else would have being, which implies that God shares his being with everything else we believe to exist. That is, everything that has being does so by participation in the One who is Being (and yet is beyond being). He is also the source of all other perfections, goodness, truth, beauty. It is because of him that we are able to understand a good tree from a bad one, a hot fire from a hotter, a beautiful painting from an ugly one.

Finally, in the Fifth Way we get an argument from the final cause, that is the thing for which or toward which all things move. The essential idea is as follows: an acorn when it falls to the ground under the right conditions becomes an oak tree. This is not an accident. It isn’t as though it could fall to the ground and become a tiger (probably), or at least the reason it doesn’t do so is because, somewhere within the natural chain of events, it is decided that it won’t do so. The one deciding that is God. God is the one who directs all things to their final cause. Acorns into oak trees, eggs into birds (or breakfast), colts into stallions, fawns into bucks, pups into dogs, etc., etc. What Aquinas does not say directly here, but does say later in the Summa is that God is actually the final cause of all things. That is, not only is God the one directing all things to their final cause, but is, ultimately, their final cause itself (though this brings up against nature/grace debates I do not intend to invoke today).

Now, to turn us to deification. In all the Five Ways we see God described as the being who is utterly different from creation (as its Creator) and yet as the one who shares himself with creation by moving, causing, being its source, sharing his perfections, and serving as its final end. This is, in essence, a rather simplified view of deification. Deification (which in the Christian East is often defined as participation in God) can only happen because God is Uncreated and we are created. That is, a thing can only be deified if it isn’t God in the first place. So Aquinas shows us that we are not God, we are different from him because he is our mover, cause, etc., etc. This is what makes it possible for God to be close to us, to share himself with all creation in general way. And it is this that allows for humans (and to a broader extent all creation) to be deified. It is, of course, important to remember that the Five Ways only give evidence of a doctrine of theosis in Aquinas, they are not the only evidence, but I think them rather good and for this reason. When Aquinas sets out to describe God, using Aristotelian philosophy, he does so in a way that entails God as deifier. God as the one who, if he creates, does so in order to deify.

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David Mosley has a PhD in theology from the University of Nottingham. His research focuses on theosis and the role it plays, and should play, in human life, particularly human creativity. He is the author of the just-published fantasy novel On the Edges of Elfland. His book Being Deified will soon be published by Fortress Press and can be pre-ordered at Amazon. David blogs at Letters to Elfland.

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5 Responses to The Five Ways and Deification

  1. Fr Aidan Kimel says:

    Thank you so much, David, for writing this reflection on the Five Ways for my blog!

    Liked by 1 person

  2. Tom says:


    This is a very helpful short introduction to the 5 Ways. Thanks very much!

    As I got into the 4th Way (Gradation), it dawned on me that it represents a way I’ve been arguing for apatheia (as God’s undiminished/unimprovable aesthetic satisfaction or beatitude). But never mind that. I’d like to ask about Aquinas’ argument for the 4th way. I agree that all moral sensibility implies an absolute standard; all ‘goods’ imply ‘the Good’ as such. But I’m not sure Aquinas’ example of ‘fire’ (or ‘friction’) works. Are we really to suppose there is a supreme instance of ‘friction’ or ‘heat’? I’m not a scientist, but it doesn’t seem to me that friction or fire is the kind of thing (perfection) that betokens an absolute instance of its kind. I don’t see the problem faced in making sense of fire if we suppose there is no ultimately, supreme, instance of fire. So I suppose my question is, does every instance of a kind or genus entail an absolute standard for that kind? It doesn’t seem to me that it does, or that we need to insist that it does in order to argue that there are some ‘kinds of kind’ (I get credit for that!) that do imply their own supreme perfection. So while I wouldn’t have gone to ‘fire’ to demonstrate an instance of the 4th way, it does seem evident enough that ‘morality’ does imply such gradation.




    • Iain Lovejoy says:

      Is the “4th way” an argument that relies on Plato’s concept of ideal forms, which is where the problem lies? (Not being particularly knowledgeable on Aquinus or Plato this is something of a guess.)
      If so, then wouldn’t the only “kind of thing” it works for be morality (if you aren’t a fan of Plato).
      If that is so, would the nearest to the idea that fits with more modern modes of thought be the problem of deriving an “ought” from an “is”, i.e. not conceiving of God as the most moral being by some objective standard, but rather the source or standard from which the “good” itself is derived?


      • John H says:

        Dear Tom,

        In response to your query, modern science does indeed conceive of a supreme instance of heat in the universe, namely, the temperature of the early universe at the instant of its creation approximately 14 billion years ago. At the moment of creation, it is theorized that the entire mass of the universe was compressed to a size smaller then a pin, This is called the Big Bang Singularity and at this point the laws of physics basically break down and the temperature of the Big Bang Singularity approaches infinity.

        A mere instant after the Big Bang, an instant known as the Planck time 10(-43) seconds after the cosmic fireball, the temperature was about 10(31) degrees Kelvin. And approximately 100 seconds post Big Bang, the temperature would have fallen to about 10(9) degrees Kelvin, i.e. one billion degrees, still far hotter then the central portion of any star within our universe.

        Of course, Aquinas conceived of fire as being the absolute manifestation of heat, because his ideas of the physical universe were governed by Aristotle’s Physics. But of course we now know that the temperature of fire can’t hold the candle to the heat within the interior of our sun and certainly not the mind boggling temperatures found in the early universe. So maybe God is fire after all, as Pascal poetically noted, or at least the fire of the primeval fireball known as the Big Bang.


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