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Kant on the Cosmological Argument

Kant’s objection

The cosmological proof appears to begin safely from experience: something exists, and contingent existence demands an absolutely necessary ground. But the category of causality has legitimate use only within possible experience, not as a bridge to a supersensible being. Even if an unspecified necessary being were granted, experience cannot identify it as the unique, all-real God. That identification covertly depends on the failed ontological proof.

Textual location

Kant, Critique of Pure Reason, A603/B631-A614/B642, “On the impossibility of a cosmological proof of God’s existence.” His model is Leibniz’s proof a contingentia mundi, from the contingency of the world.

Kant’s reconstruction of the proof

  1. If anything exists, an absolutely necessary being must exist.
  2. At least I exist.
  3. Therefore an absolutely necessary being exists.
  4. An absolutely necessary being must be completely determined through its own concept.
  5. Only the ens realissimum, containing all reality, is completely determined a priori.
  6. Therefore the absolutely necessary being is the ens realissimum - God.

The appeal to “I exist” gives the proof an empirical opening. Unlike the ontological argument, it does not appear to infer an object directly from a definition. Kant’s charge is that experience performs only the first step and cannot do the decisive work.

The two-stage failure

Stage 1: from contingent existence to an absolutely necessary being

Kant identifies several illicit assumptions at A609/B637-A610/B638.

Causality is extended beyond possible experience

For Kant, the category of cause has objective validity because it structures temporal experience: events are determined according to rules within the sensible world. The cosmological proof uses the rule outside every possible experience, asking for a cause that is not itself in the spatiotemporal causal order. That transcendent application lacks a criterion of meaning or verification.

This is not merely the claim that we have not yet observed a first cause. It is the stronger critical claim that the conditions under which “cause” yields knowledge do not license its use for a supersensible object.

An infinite series is treated as requiring a first member

The proof assumes that a series of contingent causes cannot continue indefinitely and must terminate in an absolutely necessary cause. Kant’s antinomies show why reason generates conflicts when it treats the world as a completed whole. The regulative demand to keep seeking conditions does not entitle us to declare that the series is complete in a first, unconditioned object.

Removing conditions does not produce a positive concept

Calling something “unconditioned” tells us that it does not depend on another condition. It does not tell us how such a being is possible or what its necessity consists in. Negating dependence is not the same as positively conceiving absolute necessity.

Logical and real possibility are confused

A concept that contains no overt contradiction may be logically possible. It does not follow that the synthesis of properties in an absolutely necessary being is really possible. Speculative reason lacks an experiential basis for that transition.

Stage 2: from a necessary being to God

Suppose, for argument’s sake, that the proof has reached some necessary being. Nothing in the empirical premise identifies it as omniscient, omnipotent, perfectly good, personal, unique, or the totality of reality.

The proof therefore argues that only the ens realissimum is adequate to necessary existence. But this means:

If something is absolutely necessary, it is the ens realissimum; therefore the ens realissimum exists necessarily.

The convertible relationship between necessary being and ens realissimum reintroduces the claim that the concept of the most real being entails necessary existence. That is exactly the ontological proof that the cosmological argument claimed to avoid.

Kant’s memorable image is that the proof presents two witnesses - experience and pure reason - but there is really one witness changing clothes and voice.

What the critique does and does not target

Kant’s reconstruction is especially suited to Leibnizian contingency arguments that infer an absolutely necessary being and then identify it with the all-real God. “Cosmological argument,” however, names a family:

  • arguments from contingency or sufficient reason;
  • arguments from temporal beginning (kalām);
  • arguments from change or essentially ordered causes;
  • arguments from sustaining or grounding dependence.

Contemporary defenders may deny that their argument uses Kant’s category of event-causation, that it must terminate a temporal series, or that the divine attributes are derived ontologically. Thomists, for example, often distinguish a hierarchical sustaining cause from a first event in time. Kant’s critique still raises a central challenge: what licenses extending causal or explanatory principles from conditioned experience to an unconditioned, supersensible ground, and how is that ground identified as God?

Relation to Robertson

Robertson condenses the cosmological argument into the claim that causal chains cannot continue infinitely and therefore require a first cause. That is a useful introductory picture, but narrower than Kant’s actual discussion, which emphasizes contingency, absolute necessity, the limits of causality, and the illicit identification of the necessary being with the ens realissimum.

Robertson is strongest on the proof’s position in the dependency chain: the design proof must appeal to a first necessary creator, and the cosmological proof must then appeal to the ontological proof.

A compact evaluation

QuestionKant’s answer
Can experience establish that something exists?Yes.
Can experience establish an absolutely necessary supersensible being?No.
Can the category of causality be used constitutively beyond possible experience?No.
Does an endless search for conditions prove a first condition exists?No.
If a necessary being is granted, does experience show it is the ens realissimum?No.
What supplies that identity?The ontological proof, covertly.

Sources