In several recent online discussions among classical theists, I’ve encountered a recurring argument intended to support the doctrine of divine simplicity (DDS). This argument, frequently hinted at but rarely fully developed, employs a reductio ad absurdum strategy. According to proponents of this argument: if God’s thoughts were distinct from His essence, it would lead to an infinite regress of explanatory dependence; thus, the assumption is false and there must be at least one thought identical to God. Despite frequent references to this argument in contemporary discussions, it has seldom been explicitly formalized or critically scrutinized in detail. Motivated by curiosity, I have reconstructed and clarified its logical structure to address this gap.
In this post, my goal is to clearly articulate why I find this reductio argument unpersuasive, highlighting the questionable assumptions about divine cognition and causation upon which it relies. To set the stage for my critique, I’ll first present a formalized version of the argument, clearly outlining its logical structure, before examining the premises in detail to explain why the conclusion may not hold as securely as its advocates suggest.
Reductio for Divine Simplicity
To address the lack of a fully developed version of this argument, I’ve formalized it drawing on hints from discussions and existing literature. The argument assumes that God’s thoughts are distinct from Him and derives a contradiction, suggesting this assumption should be given up. Below, I define the necessary constants and predicates, then present the premises and derivation:
Constant:
(G): God
Predicates:
ThoughtOf(t, x): t is a thought of x
Causes(x, y): x causes y
Creature(y): y is a creature
Decision(d): d is a divine rational decision
ToCreate(d, y): d is a decision to create y
ExplanatorilyDependsOn(a, b): a explanatorily depends on b
The Argument
Assumption (A): God is distinct from His thoughts.
[∀t (ThoughtOf(t, G) → t ≠ G)]
If an entity’s thoughts are distinct from it, it causes those thoughts.
[∀x ( (∀t (ThoughtOf(t, x) → t ≠ x)) → (∀t (ThoughtOf(t, x) → Causes(x, t))) )]Everything caused by God is a creature.
[∀y (Causes(G, y) → Creature(y))]Every creature explanatorily depends on a divine rational decision to create it.
[∀y (Creature(y) → ∃d (Decision(d) ∧ ToCreate(d, y) ∧ ExplanatorilyDependsOn(y, d)))]Every divine rational decision depends on one of God’s thoughts.
[∀d (Decision(d) → ∃t (ThoughtOf(t, G) ∧ ExplanatorilyDependsOn(d, t)))]Ungrounded infinite explanatory regresses are impossible.
To make the derivation of the contradiction more evident, consider the following explanation:
From A and P1: If God’s thoughts are distinct (t ≠ G), God causes them.
[∀t (ThoughtOf(t, G) → Causes(G, t))]From P2: Each thought caused by God is a creature.
[∀t (ThoughtOf(t, G) → Creature(t))]From P3: Each creature-thought depends on a divine decision (d₁).
For thought t₁, there exists d₁ such that ExplanatorilyDependsOn(t₁, d₁).From P4: Decision d₁ depends on another thought t₂.
ExplanatorilyDependsOn(d₁, t₂), where ThoughtOf(t₂, G).Since t₂ is a thought of God, by P2 and P3, it’s a creature needing another decision d₂, which by P4 depends on thought t₃, and so on.
This creates an infinite chain:
t₁ ← d₁ ← t₂ ← d₂ ← t₃ ← ⋯
where each element depends on the next.P5 asserts that such ungrounded regresses are impossible, yielding a contradiction.
Conclusion: The assumption (A) is false. Thus, there must be at least one thought identical to God: [∃t (ThoughtOf(t, G) ∧ t = G)].
Analyzing the Argument
I find this reductio unpersuasive due to several questionable assumptions about divine cognition and causation. Recall that P2 maintains that everything caused by God is a creature. At first glance, this premise might seem plausible, especially when thinking about the traditional examples of creation: planets, angels, humans, animals. These are all indeed creatures, each dependent entirely on God’s causal power. However, upon further reflection, P2 is incredibly problematic as it attempts to do far too much with very little.
The first and perhaps most critical issue is that P2 overextends the notion of “creature” beyond its traditional theological boundaries. Typically, theists define a “creature” as something contingent that exists distinctively outside of God (ad extra). More specifically, a contingently existent substance is a creature iff it’s existence is ultimately caused by the free will of God. Three key features jump out of this definition:
Contingency: A creature’s existence isn’t necessary
Substantiality: It must be a distinct substance (something with its own being ad extra).
External Causation: it’s being is ultimately grounded in a free divine act of creation.
But now consider God’s thoughts, do His thoughts fit the bill? Even if we were to grant (A), it doesn’t automatically follow that these thoughts are “creatures” as outlined above. They still lack contingency. Theists of any stripe will no doubt be quick to ascribe eternal (often necessary) status to divine ideas or self-knowledge. These same theists will also deny that God’s thoughts are discrete, world-bound entities that He creates by a free creative act. Divine thoughts are traditionally considered part of God’s internal life or operation.
This leads directly into a second point: the critical distinction between internal divine operations and external productions. In classical theology, God’s internal operations include His necessary acts of self-knowing, self-loving, or the Trinitarian processions such as the Father’s eternal generation of the Son or the spiration of the Holy Spirit. By contrast, external productions are contingent creative acts, like God creating the universe or sustaining contingent beings.
P2 overlooks this crucial distinction entirely. If we acknowledge this difference, then even if God’s thoughts were caused in some internal sense (as some theologians have argued), they would remain distinctively internal to God’s necessary, eternal divine life. Such internal acts would not be creatures. Equating internal acts of divine self-knowledge or divine decisions with contingent external beings introduces serious conceptual confusion.
The third problem is somewhat related to the second, but is subtler yet equally damaging. P2 implicitly conflates epistemic (or causal) dependence with ontological creatureliness. To say something is caused by God might mean several very different things. Consider our human analogy: my beliefs depend on (or are caused by) my cognitive faculties, but clearly, these beliefs are not “creatures” in the sense of independent, contingent entities like rocks or animals. My beliefs are rather internal cognitive states, not separate beings.
Similarly, God’s thoughts, even if somehow dependent or caused, would still be internal states of divine cognition. Without explicitly acknowledging and justifying the jump from “caused by God” to “being a creature,” the argument presupposes exactly what it needs to prove.
Fourthly, the explanatory chain (t₁ ← d₁ ← t₂ ← d₂ ← t₃ ← ⋯) seems specifically constructed around thoughts that are caused or created via a divine decision. This framework appears most applicable, if at all, to thoughts whose content corresponds to contingent states of affairs that God chooses to bring about or know in a particular way related to His will/actions. So, even if the argument successfully forces us to conclude that the content of thoughts about states of affairs God causes must exist in God (perhaps identically, to avoid the regress), this seems insufficient to establish that all propositions exist in God's intellect as identical contents of divine thought. What about propositions that don't seem contingent on a specific divine creative decision in the same way? What of mathematical and logical truths? What of propositions about God himself? What of propositions about impossibilia?
In short, binding the term ‘creature’ to every divine effect collapses the very distinction classical theists rightly insist upon. God’s thoughts aren’t contingent substances in the created order. They are part of God’s own eternal life. Equating internal divine operations with creatures thus overextends the concept far beyond its intended theological boundaries.