The Library · Arguments for God's Existence

Arguments for God's existence

The classical arguments, each shown the same way: the argument whole, in its author's own words; the one premise the dispute turns on, marked; the strongest objection to that premise, in the objector's own words, beside it; and the cost of keeping or denying it, weighed both ways. The conclusion is yours to draw.

Why this section exists

The Catholic Church teaches that God's existence can be known with certainty by the natural light of human reason (the First Vatican Council, 1870) — which is why a Catholic study library can host these arguments, and their sharpest objections, without anxiety. That teaching is the section's warrant, not a verdict on any single argument: Hume, Kant and Gaunilo sit here at full strength.

Cosmological Available

The Argument from Contingency

From the existence of things that need not have been, to a being that must exist.

Turns on: The Principle of Sufficient Reason Read the argument →

Act & potency · Aristotelian Available

The Argument from Change

From the reality of change — a potential being made actual — to a first, purely actual cause that changes without itself changing.

Turns on: That no potential can actualize itself Read the argument →

A priori Available

The Ontological Argument

From the very idea of God — "that than which nothing greater can be conceived" — to God's existence.

Turns on: Whether existence is a perfection Read the argument →

Cosmological In preparation

The First-Cause Argument

From the chain of causes at work here and now, to a first, uncaused cause.

Turns on: Whether an essential causal series can regress forever

Teleological Available

The Argument from Design

From the order and apparent purpose of nature, to a designing intelligence.

Turns on: The inference from design to a designer Read the argument →

From conscience In preparation

The Moral Argument

From the binding force of moral obligation, to a ground or lawgiver for it.

Turns on: Whether moral obligation is real and objective

Thomas Aquinas In preparation

The Five Ways

Aquinas's five compressed proofs — from motion, cause, contingency, degree, and governance.

Turns on: A different load-bearing premise in each

Cosmological In preparation

The Kalam Argument

From the claim that the universe began to exist, to a cause of that beginning.

Turns on: Whether the universe began to exist

Prudential — a different kind In preparation

Pascal's Wager

Not a proof that God exists, but an argument about how it is rational to live under uncertainty.

Turns on: The decision under a specific payoff

Contingency is the first built in full; the others are in preparation, each to follow the same even-handed pattern. Every argument is shown with its strongest objection, in the objector's own words — the library takes no side.

The living debate

The classical statements and their classic objections are public domain, and hosted here in full. The modern revivals and critics — Pruss, Plantinga, Craig, Swinburne, Mackie, Oppy and the rest — are under copyright, so we don't host them: each argument page ends with cited links to where that debate lives, and the neutral scholarly surveys are the calmest doors in.

Stanford Encyclopedia of Philosophy

Peer-reviewed survey entries — the neutral map of each argument's live debate

Internet Encyclopedia of Philosophy

Accessible survey entries on the arguments in Western theism

Each argument opens the same dated, source-by-source page the Contingency argument uses: the words are the philosophers' own; the numbered form, the marked hinge, and the cost lines are clearly-labelled apparatus, each attributed to a named thinker. Nothing here is an AI summary, and no page reaches a verdict.