Descartes week 4

Meditations

Fifth and Sixth

Fifth Meditation Core Idea

Mathematics reveals the true structure of reality.

• geometrical truths are clear and distinct,

• and whatever we clearly and distinctly perceive must be true because God is not a deceiver.

So mathematics becomes the foundation for understanding nature

Clear and distinct ideas

Descartes says that he can clearly and distinctly imagine extension. 

It is not just our ideas of numbers that are clear and distinct, but also our ideas of space and objects with mass, which is what we imagine when asked to imagine quantity.

Triangle example

Descartes asks us to imagine a triangle. Even if there is no triangle that exists or has ever actually existed outside of our minds, there is still an essence of that triangle, something unchangeable, essential, that does not depend on our imagination to exist. Triangles would still have three sides and three angles. This is a true and immutable nature.

We can find a form or an essence just by imagining shapes, because they have an essence that they couldn’t exist without. 

God’s existence (ontological argument)

God is an idea I find within me in the same way I find shape and number.

If you are thinking of God, then you are thinking of something that necessarily exists. Necessary existence belongs to God’s essence.

Therefore, God necessarily exists