The most striking section for me was the section on divine simplicity: the idea that God is not comprised of parts. Despite the title of my blog (“Think Theology”), Twitter handle (“AJWTheology”) and undergraduate degree (“Theology”), I have never really studied theology properly; my focus and training have always been in Biblical Studies. So the fact that God is simple is something I have always accepted, but without really seeing its importance. For me, affirming divine simplicity is like affirming that my wife is 5’5”: she is, but that is certainly not one of the first few things I would want to say about her. Dolezal thinks the doctrine is far more integral to the divine life than that, and I suspect he’s right.

Here’s Irenaeus, in Against Heresies:

He is a simple, uncompounded Being, without diverse members, and altogether like, and equal to Himself, since He is wholly understanding, and wholly spirit, and wholly thought, and wholly intelligence, and wholly reason, and wholly hearing, and wholly seeing, and wholly light, and the whole source of all that is good—even as the religious and pious are wont to speak concerning God.

Athanasius, Against the Heathen:

For God is a whole and not a number of parts, and does not consist of diverse elements, but is Himself the Maker of the system of the universe. For see what impiety they utter against the Deity when they say this. For if He consists of parts, certainly it will follow that He is unlike Himself, and made up of unlike parts.

Augustine, City of God:

It is for this reason, then, that the nature of the Trinity is called simple, because it has not anything which it can lose, and because it is not one thing and its content another, as a cup and the liquor, or a body and its colour, or the air and the light or heat of it, or a mind and its wisdom. For none of these is what it has.

Boethius, De Trinitate:

But the Divine Substance is form without matter, and is therefore one, and is its own essence. But other things are not their own essences, for each thing has its being from the things of which it is composed, that is, from its parts. It is This and That, i.e. it is its parts in conjunction; it is not This or That taken apart.

Anselm, Proslogion:

For whatever is composed of parts is not completely one. It is in some sense a plurality and not identical with itself, and it can be broken up either in fact or at least in the understanding. But such characteristics are foreign to you, than whom nothing greater can be thought. Therefore there are no parts in you, Lord ... You exist as a whole everywhere, and your eternity exists as a whole always.

Thomas, Compendium Theologiae:

The first mover must be simple. For any composite being must contain two factors that are related to each other as potency to act ... Hence the first of all beings cannot be composite ... Hence the truth remains that the first of beings must be absolutely simple.

Owen, Vindicae Evangelicae:

He, then, who is what he is, and whose all that is in him is, himself, hath neither parts, accidents, principles, nor anything else, whereof his essence should be compounded.

Turretin, Institutes of Elenctic Theology:

The orthodox have constantly taught that the essence of God is perfectly simple and free from all composition.

We could go on (and Dolezal does). And while to some this might sound like scholastic pedantry running amok, it is worth bearing in mind the implications all this has: if God is simple in this classical sense, then it is almost impossible to see him as genuinely mutable, passible, temporal or dependent. “I, the Lord, do not change” (Mal 3:6).