Meditations on First Philosophy
1641 · René Descartes
Core ideas
- Systematic doubt clears away every belief that can be doubted.
- The thinking self is the one certainty that survives doubt.
- Clear and distinct perceptions are the mark of truth.
- Mind and body are really distinct kinds of substance.
Summary
Across six meditations, Descartes undertakes to demolish all his beliefs and accept only what is indubitable. He suspends trust in the senses, in the external world, even in mathematics, imagining a deceiving demon who falsifies his every thought. Yet one thing resists all doubt: that he is thinking. 'I think, therefore I am' becomes the first certainty.
From the thinking self he argues outward — to the existence of God as a non-deceiver, and from there to the reliability of clear and distinct ideas and the existence of the material world. Along the way he argues that mind and body are distinct substances, a dualism that frames the modern problem of consciousness.