Part IV
Descartes expounds his foundational metaphysical truths: Cogito ergo sum, the nature of mind and body, and proofs of God's existence.
4 argumentative units
- 01Method of doubt and the cogito: I think, therefore I am
Descartes resolves to reject as false everything he can doubt — senses, geometry, waking experience — and discovers that the one thing that cannot be doubted is that he who thinks must exist.
- 02The nature of mind as distinct from body
Descartes concludes that he is a thinking substance whose existence requires no body or place, establishing that mind is wholly distinct from body and more easily known than it.
- 03Proof of God's existence from the idea of a perfect being
From his own doubting and imperfection, Descartes infers that the idea of something more perfect than himself must have been placed in him by a nature that actually possesses all perfections — that is, God.
- 04God as guarantor of clear and distinct ideas, and of waking truth
Descartes argues that God's veracity guarantees the principle that what we clearly and distinctly conceive is true, and that God's perfection ensures that our waking perceptions are more reliable than dreams.