This is all true, but I’d like to add some specifications. When we speak about “natures” there a number of different possible meanings. The one that matters for the Catholic doctrine of God is the meaning indicated by the Greek word “physis,” which occurs in the New Testament, most importantly at 2 Pet 1:4, and which has a very definite meaning. The *physis *of an object is that principle of its existence that can be cited in answer to the question “What is it?” For instance, “dog, tree, aluminum, man” can all answer such a question by reference to some kind of nature, namely, “dogness, treeness, aluminumness, manhood.”
The nature of a thing might therefore be defined as “the formal principle of a thing’s existence.” By formal, I mean something distinct from matter. For example, there is no material object “manhood,” although manhood as a form exists in a large number of material objects. While all human beings are made of different material, they all have the same nature because the from of “manhood” is common to all, and all people are made of some matter.
By “element of existence” I mean that a nature is not necessarily the only thing that goes into making a being exist. For instance, we have just seen that human nature is not material, and yet there needs to be some material for the form to be in. In fact, the very notion of form implies matter. (There is no such thing as “manhood,” as a separate being, apart from real, existing men.)
But while nature is a form without specified matter, it does not follow that all forms are natures. For instance, having blue eyes is a form, but cannot answer the question “What is it?” when asked about a man. All forms that do not answer to “What is it?” are accidents, not natures.
Now, before someone objects that this is all so much Greek philosophy, let me remind you than I am not philosophizing about nature, but am defining a biblcal term, which has a meaning in the language it was written in. In modern parlance, we are wont to use “nature” in ways that are very foreign to the meaning of physis. For instance, when we say that a person is “good-natured,” we mean that the person is kind in his personal habits and disposiiton. But personal habits and dispositions are not natures, but accidents. The same man can be virtuous at one time in his life and vicious at another, but that does not amount to a change in his physis, but in his additional, accidental attributes. A physis is the thing that remains static at all times in a being’s existence. That is why it can answer the question “What is it?”
Now, I doubt that the above paragraphs will be very exciting or easy for anyone to read. It was a bit dull even to write it all out. But it matters, bigtime. The reason is that on the Mormon account of exhaltation, the “divine nature” that we come to acquire is not a tranformation in terms of what we are. We already belong to same species as heavenly Father, who is the same kind of thing as we are and have always been. That is to say, Mormon theology denies a difference between the divine *physis *and human physis. What we acquire in exhaltation, therefore, are additional attributes, accidental properties, like moral perfection, power and dominion. These things elevate our status and dignity, but they are not transformations in physis, and cannot be, by definition. Consquently, it is utterly improper to describe Mormon exhaltation as “becoming partakers of the divine physis,” since on the Mormon, materialist account, God’s perfections are distinct from his physis. It is only if we overlook the historical meaning of the Greek word and lighting upon a secondary, modern, improper meaning of “nature” that this text seems to support Mormonism. In reality, to become a partaker of the divine *physis *can only make sense on the presupposition that human physis is something different from God’s, and thus Mormonism falls before its own favorite proof-text.