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The Rationalists: DescartesThe Rationalists: Descartes

Rational Truth, God (the return), Rational Truth, God (the return), and the Cartesian Circleand the Cartesian Circle

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Meditation 4: Reminder Meditation 4: Reminder

Theory of Error: Misuse of Will outside of the limits of our understanding

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Theory of Truth: Use our will within the limits of our understanding!

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OutlineOutline

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Meditation 5:

1. Rational truths

2. Existence of God – Ontological Argument

3. Cartesian Circle

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Rational TruthsRational Truths

Distinct ideas about the bodies: mathematical notions – extension in time

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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

Rationalism vs EmpiricismRationalism vs Empiricism

EMPIRICISM RATIONALISM

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

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Ontological ArgumentOntological Argument

A mathematical demonstration: idea of God is innate like the idea of the triangle – we can make the same kind of reasoning

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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

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Cartesian CircleCartesian 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

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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

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Meditation 5: ConclusionMeditation 5: Conclusion

We started the reconstruction: rational truths recovered

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Descartes’ theory of ideas: rationalism

What remains to show: the existence of the external, material world.