René Descartes - Philosophy and Learning
René Descartes (1596-1650)
French philosopher (pictured right) and mathematician who invented the graph.
The founder of the modern theory of knowledge (epistemology).
His most famous book
What did he say about learning?
1. “I think therefore I am”
In Latin “cogito ergo sum”, this famous statement is better translated as
‘I am thinking, therefore I exist’
(i.e. thinking is essential to life).
Thinking is the only thing you can be certain of, because your senses (hearing, sight etc.) may
tell you that something is real or true when it isn’t.
For example, you may be dreaming or being misled (see point 2).
2. Reason and analysis
To learn you must rely not on your imagination and senses but on your thinking i.e. reason
and logical analysis (called rationalism).
“True knowledge must come from human reason alone”, he said. So:
- start with the facts (possibly resulting from experiments)
- draw logical conclusions that can’t be contradicted.
Your senses and experiences are unreliable, because you can never be certain about what you see (see point
Descartes described the example of a honeycomb wax: hard when cold, liquid when hot, but still the same piece of
3. What can I know?
This is the most important question that comes from his work.
To be happy you must learn and increase your knowledge by
- asking the right questions.
- thinking logically (see point 2).
4. Question all your beliefs
This is often known as the Method of Cartesian Doubt (Cartesian means ‘from
Treat all your beliefs as false and reject any, if there is any doubt about their
You should only believe something, if you are absolutely certain that it:
Only one false belief will badly affect the truth of your other beliefs like a rotten
apple in a barrel of apples.
5. Mind and body
The mind and body are separate (called dualism) and interact. So it is possible (as
Descartes believed) that the mind can outlive the body.
a) the mind affects the body
(like positive attitudes help your health)
b) the body affects the mind
For example, exercise helps you to relax and concentrate better.
6. Clearly explain something
Everything should be as simply explained as possible but not simpler (as Einstein (pictured below) later believed).
Key quotes on learning and
I think, therefore I am
Doubt is the origin of wisdom.
Key quotes on
It is not enough to have a good mind. The main thing is to use it well.
I made every mistake that could be made. But I just kept pushing.
Key quote on
To know what people really think, pay regard to what they do, rather than what they say.