This post is the fourth in a short blog series featuring important figures in the history of natural history.
René Descartes (1596-1650) was a scientist, mathematician and philosopher. He is regarded as the father of modern western philosophy, and is the man behind the statement Cogito ergo sum, translated as “I think, therefore I am”. So why should scientists know and care about him today? Because Descartes changed science by changing the way humans think about the natural world.
Before Descartes, doctors and scientists were trained to study the world through the lens of Aristotle’s works. They followed Aristotle’s philosophies on the cosmos and the soul, and believed that all matter was comprised of the four elements (earth, water, air and fire), which corresponded with the four humours of the human body (black bile, phlegm, blood and yellow bile). An imbalance in the humours was thought to cause illness, so doctors would try to treat sick patients by balancing the humours, leading to practices such as bloodletting.
These scientists and doctors sought to understand nature by studying the cosmos and the soul, but Descartes argued that we can never know what the soul is. Instead, Descartes thought to study life by studying the mechanisms behind it. His Discourse on Method (1637) encouraged scientists to question and test hypotheses through the use of experimentation and deductive reasoning.
Descartes was responsible for a paradigm shift in how humans think. It was Descartes who instructed scientists to focus on fact, not on the abstract, paving the way for modern science.