René Descartes

The father of modern philosophy and one of the founders of analytic geometry. His Discourse on Method (1637) launched the project of grounding all knowledge in the single certainty 'Cogito, ergo sum' (I think, therefore I am). He spent most of his adult life in the Dutch Republic, which offered the religious freedom his radical scepticism required. He died in Stockholm, having accepted Queen Christina of Sweden's invitation to teach philosophy at five in the morning.

• Roles: Philosopher, Mathematician, Scientist