1. 1 The Rationalists: Descartes Rational Truth, God (the return), and the Cartesian Circle Soazig Le Bihan - University of Montana

2. 2 Meditation 4: Reminder Theory of Error: Misuse of Will outside of the limits of our understanding Soazig Le Bihan - University of Montana Theory of Truth: Use our will within the limits of our understanding!

3. 3Outline Soazig Le Bihan - University of Montana Meditation 5: 1.Rational truths 2.Existence of God – Ontological Argument 3.Cartesian Circle

4. 4 Rational Truths Distinct ideas about the bodies: mathematical notions – extension in time Soazig Le Bihan - University of Montana These ideas are innate: I discover them in my mind While they “live” in my mind, their truth is still independent of my mind: -I did not fabricate them -They have true properties that are independent of my mind (even if they exist in my mind) Rejection of empiricism: not all abstract ideas can come from the senses

5. Rationalism vs Empiricism EMPIRICISMRATIONALISM All knowledge comes from experience Some knowledge comes from pure reason (indep. of experience) Knowledge not perfectly grounded – different levels of skepticism / agnosticism Knowledge from pure reason is superior to knowledge from experience – true knowledge Mathematical truths and logic: generalization from the senses and void of content Mathematical truths and logic: - Part of our hardware - Necessary Truths Metaphysics: Only sensible, observable bodies exist Metaphysics: Not only sensible bodies, but also ideas and/or laws etc. exist Soazig Le Bihan - University of Montana5

6. 6 Ontological Argument A mathematical demonstration: idea of God is innate like the idea of the triangle – we can make the same kind of reasoning Soazig Le Bihan - University of Montana The argument: The idea of God contains Its existence Example: The triangle, the mountain and the valley Objections: Mountain and the valley don’t exits, different idea of God

7. 7 Cartesian Circle A vicious circle? 1.The existence of a truthful God relies on the truth of clear and distinct ideas 2.The Truth of clear and distinct ideas relies on the existence of God Soazig Le Bihan - University of Montana Answer: 1.The ontological argument is not what guarantees the truth of clear and distinct ideas (proofs of God in Med. 3, not five) 2.“truth of clear and distinct ideas” does not mean the same is (1) and (2) above: truth of an instant / eternal truth

8. 8 Meditation 5: Conclusion We started the reconstruction: rational truths recovered Soazig Le Bihan - University of Montana Descartes’ theory of ideas: rationalism What remains to show: the existence of the external, material world.