Natural Theology • Existence of God • Intermediate
Leibnizian Contingency Argument
Primary question: Why does anything contingent exist at all, and what could explain the totality of contingent things?
Argument map
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Common mistakes
Don't say
Treating the argument as claiming 'everything has a cause, so what caused God?'
Instead
State precisely that the argument concerns contingent things needing explanation, and a necessary being is by definition not contingent, so the question does not apply to it in the same way.
Don't say
Assuming PSR must apply to literally every proposition without qualification.
Instead
Use the modest, defensible version of PSR restricted to the existence of contingent things, which avoids common logical paradoxes raised against a universal PSR.
Don't say
Concluding the argument alone proves the full theistic God (omniscient, morally perfect, personal).
Instead
Recognize the argument establishes a necessary being; further argument is needed to attribute additional divine characteristics.
What would change my mind? — Christian position
If a coherent account showed the universe or its fundamental laws are metaphysically necessary (true in all possible worlds) rather than contingent, the argument's second premise would collapse and the case would need to be abandoned or reworked.
What would change my mind? — Skeptical position
If the skeptic came to accept that scientific and rational practice truly commits us to explanatory closure even at the cosmic level, and found no viable brute-fact alternative more probable, the argument's PSR-based reasoning would become considerably more persuasive.
Why does this matter?
The contingency argument addresses the most basic metaphysical question: why is there something rather than nothing. It has shaped centuries of debate about the limits of scientific explanation and the rational demand for ultimate answers. Its structure underlies much natural theology, connecting to later debates on divine simplicity and aseity. Even critics regard it as one of the most rigorous and philosophically serious arguments for theism.
For further study
Primary and secondary sources on both sides of this question. Reading the strongest opposing case is part of the work, not a concession.
On the Ultimate Origination of Things — Gottfried Wilhelm Leibniz
The classical short essay presenting the contingency argument.
The Principle of Sufficient Reason: A Reassessment — Alexander Pruss
A rigorous contemporary defense of a modest PSR.
The Existence of God — Richard Swinburne
Cumulative-case natural theology including contingency reasoning.
A Companion to Philosophy of Religion — ed. Charles Taliaferro et al.
Contains detailed surveys of cosmological arguments including Leibniz's version.
The Best Argument against God — Graham Oppy
A leading atheist philosopher's critical engagement with cosmological arguments.