René Decartes

René Descartes (1596 – 1650) was a French philosopher, mathematician and scientist, who is regarded as the ‘Father of Modern Philosophy.’

Subsequently, Western philosophy can be seen as a response to his writings. He is responsible for one of the best-known quotations in philosophy, Cogito, ergo sum (I think, therefore I am).

There is direct line of descent from Socrates and Plato via St. Augustine to Descartes. They were all typical Rationalists, convinced that reason was the only path to knowledge.

As a young man, Decartes decided to travel around Europe, the way Socrates spent his life talking to people in Athens. He sought wisdom wherever he found it, be it from the people he met along the way or within himself.

He also considered the role of God in human existence.

The Method of Doubts

Descartes lived during a very skeptical period, at a time before science as we know it existed. He was the first person to use introspection to both define and express his philosophy. He wanted to make his mind better equipped to think properly, so he devised a number of time-honored techniques.

For instance, Descartes proposed that all one needs to do to solve a large problem is to break it up into much smaller, more manageable, problems.

“Divide each difficulty into as many parts as is feasible and necessary to resolve it.”


This breaking down of questioning is what Decartes called the Method of Doubts. He outlined four main rules for himself in his thinking:

  • Never accept anything except clear and distinct ideas.
  • Divide each problem into as many parts are needed to solve it.
  • Order your thoughts from the simple to the complex.
  • Always check thoroughly for oversights.

Essentially, the Method of Doubts required you to thoroughly re-examine everything you thought you knew and challenge what is understood.

Think about it.

How do you know what something is?

Have you ever thought you saw someone, or something, that you really didn’t?

Better yet, do you always know that you are dreaming, during your dreams?

For that matter, can you prove that you’re not in a highly advanced simulator right now?

As Decartes declares:

“If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.”


The Wax Argument

As a Rationalist, Descartes dismissed the senses and perception as unreliable, and to demonstrate this he created the so-called Wax Argument.

This revolves around the idea that a wax object, which has certain properties of size, color, smell, temperature, etc, appears to change almost all of these properties when it is melted, to the extent that it appears to our senses to be a completely different thing.

However, we know that it is in fact still the same piece of wax. Descartes concluded from this that the senses can be misleading and that reason and deduction is the only reliable method of attaining knowledge, which is the essence of Rationalism.

The Mind-Body Problem

Like Plato, Decartes was convinced that there was a sharp division between body and mind. As to how the mind influenced the body, Plato can not provide an answer.

Decartes set about finding one.

Using his Method of Doubts, he held that the immaterial mind and the material body are two completely different types of substances and that they interact with each other. He reasoned that the body could be divided up by removing a leg or arm, but the mind/soul were indivisible.

Descartes believed that the human body works like a machine, that it has the material properties of extension and motion, and that it follows the laws of physics.

The pieces of the human machine, he argued, are like clockwork mechanisms, and that the machine could be understood by taking its pieces apart, studying them, and then putting them back together to see the larger picture – an idea referred to as Reductionism.

The mind or soul, on the other hand, is a non-material entity that lacks extension and motion, and does not follow the laws of physics.

From this reasoning, Descartes was the first to formulate the Mind-Body Problem, which still exists today. This is the debate concerning the relationship between thought and consciousness in the human mind, on the one hand, and the brain as part of the physical body, on the other hand.

Are body the and mind the same thing or are they separate entities?

Descartes clearly identified the mind, with consciousness and self-awareness, as being separate from the brain – which was the physical seat of intelligence.

This separation of body and mind into two distinct states is known as Dualism.

Therefore, Descartes was a Duelist. In contrast, Monism maintains that there is only one unifying reality, substance or essence in terms of which everything can be explained.

The Role of God

It should be noted, however, that for all Descartes’ innovation and boldness, he does not abandon the traditional idea of God. He defined ‘substance’ (essentially meaning what the world really consists of) as, “That which requires nothing other than itself in order to exist”.

However, he concluded that the only true substance was God himself, because everything else from souls to material objects like the human body are dependent on God for its existence.

Descartes died of pneumonia during 1650 in Stockholm, Sweden, where he had been invited as a teacher for Queen Christina of Sweden. His remains were taken to his homeland of France where he was buried.

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