Arguments for the Existence of God

The branch of natural theology that evaluates whether reason alone, independent of revelation, can establish or render probable the existence of God.

Definition

Natural theology's project of assessing rational arguments — deductive, inductive, and probabilistic — that purport to demonstrate or support the existence of a divine being without appeal to scripture or special revelation.

Scope

This area covers the principal a priori and a posteriori arguments offered in support of theism: cosmological arguments from the existence or contingency of the world, the ontological argument from the concept of a maximally great being, teleological or design arguments from order and fine-tuning, and arguments from religious experience. It also covers the standard objections to each and the cumulative-case strategy that treats them jointly as probabilistic evidence. It does not cover arguments against God's existence such as the problem of evil, which is treated as a separate area.

Sub-topics

• Arguments from Religious Experience
• The Cosmological Argument
• The Ontological Argument
• The Teleological Argument

Core questions

• Can the existence of a contingent universe be explained only by a necessary being?
• Does the very concept of a maximally great being entail its existence, or does existence not function as a predicate?
• Does the order, regularity, or fine-tuning of the cosmos require a designer rather than chance or necessity?
• Can religious experience serve as evidence for God in the way perceptual experience serves as evidence for physical objects?
• Should theistic arguments be assessed individually or as a cumulative probabilistic case?

Key theories

Cumulative-case (Bayesian) natural theology

Swinburne argues that no single theistic argument is deductively conclusive, but that cosmological, teleological, and experiential considerations together raise the probability of theism above one-half, treating God as the simplest hypothesis that explains the universe and its order.

Modal ontological argument

Plantinga reformulates Anselm's argument in modal logic: if it is possible that a maximally great being exists, then, since maximal greatness includes necessary existence, such a being exists in every possible world and hence actually.

History

Systematic argument for God's existence runs from Anselm's eleventh-century Proslogion and Aquinas's thirteenth-century Five Ways through Paley's eighteenth-century design argument. Hume and Kant mounted influential critiques, Kant arguing that the ontological argument illegitimately treats existence as a predicate. The twentieth century saw a revival in analytic philosophy of religion, with modal logic reviving the ontological argument and probability theory reframing the cumulative case.

Debates

Whether any theistic argument is deductively sound

Critics such as Mackie contend that each classical proof fails as a demonstration, while defenders such as Swinburne concede this but argue the arguments succeed as probabilistic evidence within a cumulative case.

Whether existence is a predicate

Following Kant, many hold that 'exists' adds nothing to the concept of a thing, undermining the ontological argument; modal defenders reply that necessary existence, not existence simpliciter, is the relevant property.

Key figures

• Anselm of Canterbury
• Thomas Aquinas
• William Paley
• Immanuel Kant
• Richard Swinburne
• Alvin Plantinga
• J. L. Mackie

Seminal works

• swinburne2004
• mackie1982
• plantinga1974

Frequently asked questions

What is the difference between a priori and a posteriori arguments for God?

A priori arguments, such as the ontological argument, proceed from concepts alone without appeal to experience; a posteriori arguments, such as the cosmological and teleological arguments, start from observed features of the world like its existence or apparent design.

Do most philosophers think these arguments succeed?

There is no consensus. The arguments remain actively debated; some philosophers regard the cumulative case as making theism reasonable, while others judge that the objections, especially from Hume, Kant, and Mackie, are decisive.