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René Descartes

René Descartes was a student of mathematics and astronomy in the 1620s. This was after Galileo had begun peering into the heavens with his telescope. It was also after Galileo had written his successful book criticizing Aristotle and had promoted experimentation and the mathematical formulation of scientific ideas.

Descartes was 32 years younger than Galileo. He had a passion for understanding relationships, and he worked this into his invention of analytic geometry: a coordinate system allowing geometric shapes to be expressed in algebraic equations.

His mathematics did not get him into trouble – math being hard to argue with. But his ideas beyond mathematics did. He used doubt as a tool – doubt being necessary in advancing ideas. He would be regarded as having invented a philosophical framework for the natural sciences, and he would be described as the "Father of Modern Philosophy" – like many accolades, a bit overblown.

Rene Descartes

René Descartes. He rejected empiricism but was to be considered the "Father of Modern Philosophy."

Descartes thought his philosophy compatible with the new world of science and with his Christian faith. But his philosophy offended the Church, and in 1663 the Church put Descartes' work on its Index of Prohibited Books.

Fundamentals of His Philosophy

Descartes began his philosophy by rejecting any ideas that could not be doubted. There is no mental mechanism for doubting the existence of the angel Gabriel, and a belief in Gabriel was not to be assumed as part of his foundation of thought (as it would for Muslims). Descartes began with what he could claim was beyond doubt, and that was the observation of his own existence: I think therefore I am. In Latin: Gogito ergo sum. In French: Je pense donc je suis.

Descartes felt obliged to reason his way to further conclusions. He had established the importance of doubt, but he went on to positions that others would consider dubious.

In keeping with his love of mathematics, in philosophy Descartes adhered to the rationalist school: He emphasized reason at arriving at truth rather than empiricism. Tying conclusions to sense experience was more of a British point of view, Francis Bacon, John Locke, et cetera – never mind that empiricists also believed in reason. Descartes was French, and against empiricism he used the Wax Argument: senses tell one that a piece of wax has certain characteristics, but if the wax is melted the senses are demonstrated to have been wrong – a silly argument. He was using his own sense experience in trying to refute sense experience in general.

As a "rationalist" he believed in reaching conclusions through "deduction," as had Aristotle and Thomas Aquinas. And like Anselm he offered an ontological proof of the existence of God.

Descartes proposed that the human mind and body were completely separate – what philosophers call dualism. It was a point of view that would not have an impact on how people reacted to the material world, but it would impact arguments in the field of philosophy. The philosopher John R. Searle would describe Descartes as failing to "get an adequate or even coherent account of the relationship between the mind and the body." note34

Descartes viewed the human body as working like a machine and following the laws of physics. Descartes was living in the age of vivisection. Animals were cut up to see how their bodies functioned. Humans were too. It resulted in William Harvey in 1628 discovering the circulation of blood.


Descartes proposed that the body and brain of other animals were fundamentally different from human bodies. Animals did not communicate, according to Descartes. Nor did they feel that mental condition called pain. The animal's body was a base machine. Humans, on the other hand, had feelings in the form of soul.

Humans, Descarates argued, were dualistic: having a machine-like body with consciousness that other creatures did not possess. He associated this consciousness with soul.

Descartes died of pneumonia in 1650 in Sweden at the age of 54 while tutoring the robust queen, Christina. A Catholic in Protestant Sweden, he was interred in a graveyard mainly used for unbaptized infants. Later, his remains were taken to France and buried in the Abbey of Saint-Germain-des-Prés in Paris.


Mind: a brief introduction, Chapter 1 "A Dozen Problems in the Philosophy of the Mind," by John R. Searle, 2005

The History of Western Philosophy, by Bertrand Russell, 1945

A History of Science and Its Relations with Philosophy and Religion, by Sir William Dampier, 1948

"René Descartes," Wikipedia

"René Descartes," Standord Encyclopedia of Philosophy

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