Methodical Doubt in Descartes' Philosophy

1. Descartes' Methodical Doubt

Overcoming Doubt

Descartes' methodical doubt, unlike radical skepticism, is provisional. The goal is to find a truth that is undeniable.

The Purpose

Descartes' method begins with a diagnosis applied to the era. Humanity is like a sick man who must free himself from his sickness. Descartes decides that the path to truth must undergo a destructive critique of everything we know with certainty.

The Method

Descartes' method is like having faith in critique. It is a seemingly impossible task. He asks skeptical questions, directly attacking the foundations of our knowledge. He applies skepticism to doubt our senses and reason.

1.1 First Argument: Senses and Reason

We cannot trust our senses because they often deceive us (e.g., water in rowing, distance, geocentrism). Can we trust reason? We cannot be 100% certain.

Objections to the First Argument

There are things we cannot doubt. If our senses inform us, and reason exceeds the reliability of the senses, then reason is a very reliable way of knowing.

1.2 Second Argument: Dreams

All our experiences are like images in dreams, which can be false, even if they feel true. None of our experiences escape the skeptical doubt.

Objections to the Second Argument

There are notions that resist methodical doubt, such as 2 + 3 = 5, which are independent of whether we are dreaming.

1.3 Third Argument: The Evil Genius

Descartes imagines an evil genius who makes us believe everything is false. This hyperbolic doubt leads to absolute, universal doubt. However, this doubt itself implies that something is thinking. This is where Descartes reaches a point beyond skepticism.

2. Beyond Skepticism

Descartes' Solution

Descartes argues that even if doubt is false, it leads us beyond doubt. Doubt is self-defeating because when we doubt, we think, and to think implies existence. This leads to the famous maxim: Cogito ergo sum (I think, therefore I am).

The Cogito

The act of thinking implies existence without the need for demonstration. It is a self-evident, clear, distinct, and immediate intuition. Descartes sees the self (I) as a thinking substance (res cogitans) distinct from the body (matter, res extensa).

Functions of the Cogito

1. It justifies the existence of a thinking self, independent of the body.
2. It provides a criterion of truth based on clear and distinct ideas perceived through intuition.

We should only accept as true what is obvious, clear, distinct, and immediately grasped through intuition.