Meditations on First Philosophy - Meditation I

Overview

Meditation I concerns those things that can be called into doubt. Descartes repeats much of what he established in Discourse On The Method, resolving to discard all thoughts and opinions built on bad foundations. But here he pushes the project further.

He begins with the senses. They are sometimes defective. We misperceive things, mistake objects at a distance, and are fooled by illusions. If the senses have deceived us before, how can we trust them now?

But the problem runs deeper. How can you differentiate between waking experience and dreams? In dreams, the senses seem real too. You feel, see, and hear things that vanish upon waking. If dreams can perfectly mimic reality, what grounds do we have for trusting that we are awake right now?

Descartes considers a possible escape. Surely some obvious truths should not be subject to suspicion, like mathematics or physics. Two plus three equals five whether you are dreaming or not.

But even this certainty can be undermined. Descartes introduces the Evil Demon Hypothesis: imagine there is some supremely powerful being whose sole purpose is to deceive you in everything, even your mathematical reasoning. Every time you add numbers, the demon makes you err. Every clear intuition is a planted falsehood.

This is philosophical scorched earth. If there is any reason to doubt a belief, Descartes will treat it as false. By the end of Meditation I, nothing remains standing. The ground has been cleared for rebuilding.