QuestionsDoes God exist?God, cause of the idea of the infinite
Does God exist?TheismThe idea of God in us

God, cause of the idea of the infinite

René Descartes 1596 · 1650Doubt everything to find what survives doubt.
See profile
What it claims

An infinite being, God, exists.

Why

An idea has a cause at least as real as it represents; only an infinite being can cause the idea of the infinite in me.

In short

"God, cause of the idea of the infinite" is an argument by René Descartes (Meditation III) on the question "Does God exist?" (answer: theism). Its claim: An infinite being, God, exists. According to AskPhilosophy's logic check (Z3 solver), the conclusion does follow from its 3 premises. AskPhilosophy presents 3 objections, 3 of them with a documented reply, and the original text behind each premise, checked word for word.

Meditation III
Valid

First proof of God. I find in myself the idea of an infinite being. Yet I, a finite being who doubts, cannot be its author.

P1I have within me the idea of an infinite, perfect being.
P2Every idea has a cause containing at least as much reality as the idea represents.
P3Only a truly infinite being contains as much reality as the idea of the infinite represents.
Therefore an infinite being, God, exists.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
The three premises suffice and each one is essential. The real debate is about P1 (do we really have an idea of the infinite?) and P2, a principle of causality Descartes holds to be evident "by the natural light".
Analogy. In an attic you find the detailed blueprint of a machine nobody in the village could conceive. You conclude that an engineer far more skilled than you once came by. For Descartes, the idea of the infinite is that blueprint.

Objections

3

Each objection is a conversation: click to see who replies and where the debate stands.

Hobbes 1641 · attacks premise 1

We have no idea of God, only images. Like a man born blind who feels the fire's heat without ever seeing its image, we infer an eternal cause without having any idea of it.

Descartes replies
Descartes
Hobbes takes "idea" to mean a picture in the imagination. Descartes calls an idea whatever the mind immediately conceives: in that sense we do have an idea of God.
Gassendi 1641 · attacks premise 1

The idea of God is built from our own perfections, enlarged without limit. Claiming it represents God is like drawing an elephant from a mite.

Descartes replies
Descartes
We do not conceive the infinite by negating the finite: it is the reverse, every limit is already a negation of the infinite. So the idea of the infinite comes first.
A
Arnauld 1641 · attacks premise 2

The Cartesian circle: Descartes says our clear ideas are true because God exists, but he proves that God exists by means of clear ideas.

Descartes replies
Descartes
No circle: while we attend to the proof, its evidence is enough. God is only needed to guarantee our memory of past evidence, when we no longer attend to it.
In the same family · The idea of God in us
Five common notions are enough: the religion all peoples recogniseEdward Herbert de Cherbury · 1624
Does God exist?Deism 3