Ahh, the old Essence/Energy debate, an East versus West favorite.
The real difficulty here is that we are using human philosophical concepts to build a theological language about God, and were using two different philosophical/theological “lineages” to do so. Much of this argument boils down to HOW we describe, in human
One thing to keep in mind is that the “Latin” theological tradition and explaination of “participation in God”, expressed most thoroughly and coherently by St. Thomas Aquinas, is directly derived from St. John of Damascus who utilized the Essence/Energy distinction in his work “The Orthodox Faith”. In fact, I’d argue that St. Thomas Aquinas uses pretty much exactly the same theology as St. John of Damascus, but just translates it into the Latin theological language.
Another thing to keep in mind is that the discussion of Essence and Energies is often very confusing and not at all uniform. Two different Eastern theologians will have very different explanations of them, and some explainations are much better than others IMO. For example, some theologians will speak in a way that practically divides the Essence and the Energy of God, making the Essence the “unparticipated” and the Energy the “participated” in a manner that sounds like there are two Gods, the hidden and unknowable and the knowable. St. John of Damascus, on the other hand, doesn’t make such a sharp distinction at all, and neither do most of the other ancient theologians.
What happens between the Latin tradition and the Byzantine tradition, however, is that the terms are used slightly differently, and that can lead to confusion. In the Latin tradition, “energy” and its equivalents (such as “operations”) are used to describe, for lack of a better term, the activities of God. In the Byzantine tradition it is used more broadly to describe both the activity AND the “traits” of God. It’s noteworthy, however, that St. John of Damascus makes it very clear that these “traits” and “activities” are utterly simple and not composite, meaning that what we perceive as distinctions (such as God’s Love versus God’s Justice) are actually one and the same thing. This is due to God having an utterly simple Essence, according to St. John, which points to how closely related to two things are.
The Essence, in the Byzantine tradition, is more akin to “being God”, where in the Latin tradition it is the broad term that includes both “being God” and the traits of God (what it means to be God, in other words). So in the Byzantine tradition you would never say that we share in the Essence of God, because we never ARE God in the absolute sense, even though we share in everything God “has” other than “being God”. This sharing, then, is of the Energies of God. In the Latin tradition it is said that we share in the Essence of God without being God, because the Latin use of Essence incorporates both the “traits” and the “being God”, so we can be said to participate in the Essence without at all implying that we become God (which is what would happen if you used the same terminology in Byzantine theology).
There is really no conflict at all once we remember that we’re simply using human philosophical terms to come to an analogical description of God. Both sides are saying that we participate in God without being God, and both are very, very adamant that anything less than a real participation in God destroys the foundation of the Faith (in the East this debate occured between Palamas and Barlaam, in the West it occured between the Realists and the Nominalists, with the Protestant reformers following the Nominalist theology and the Catholic Church following the Realist). The only real difference is in terminology, because where the Latins would say that we participate in the essence of fire, without becoming fire, by growing hot, since being hot is of the very essence of fire, the Byzantines would say that we share in the fire’s essential energy of heat without becoming fire.
Both are ultimately just very nitpicky ways of trying to explain a central Mystery of our Faith: we share in the Divine Nature by Grace, yet we never become God in an absolute sense. Whether you say it by using the philosophical distinction between essence and energy, or the philosophical distinction between sharing in something and being that something, you are making exactly the same analogy.
We may have our own preferences in how to express this mystery, but they remain human preferences even if one is better at highlighting certain aspects than another (and visa versa); God is not defined, He’s merely sloppily explained to the extent that human language allows.
Peace and God bless!