No one comes close to the ingenuity of the man who changed our fundamental understanding of nature (and ourselves) like the legendary French philosopher, scientist and mathematician Rene Descartes. He was not an inventor like Graham Bell or Galileo but he did something iconic. At a time in history when curiosity was suppressed in the name of conformity to the authority of religion and prevailing philosophy, he was the first among (the other was Francis Bacon) to assert that: “There is need of a method for finding out the truth.” As one of the history’s most intriguing minds, Descartes laid the foundation to reason and critical thinking.

## There is need of a method for finding out the truth –

René Descartes

What happens when a random flash of insight is coupled with an incredible capacity to comprehend and expand upon it? Rene Descartes life is filled with such impactful epiphanies. After determining that the typical path to a standard career wasn’t for him, Rene Descartes made a huge (and uncharacteristic) leap of faith by moving to Holland to join the military. Quickly realizing that he wasn’t necessarily cut out to be a soldier, Descartes made his mark as an engineer, relying on his keen mathematical sense rather than his physicality.

Years of intense education convinced him of only one thing – he could learn more by way of his own philosophy and studying science alone, without the distraction of textbooks and the authority of teachers. He was right. One seemingly ordinary day, as Descartes lay in bed daydreaming, he idly watched a fly buzz about his room. He came to a realization at that instance – the position of the fly at any time could be represented by three numbers – providing a distance from the three walls that met in the corner. We know these today as the Cartesian co-ordinates. In school, we learned that any point on a graph is represented by two numbers, corresponding to the distance along the x axis and up the y axis.

What did this mean? It meant that any shape could be represented with just a set of numbers related to one another by mathematical equation. The discovery, once published, transformed mathematics from its roots. This discovery made geometry able to be analyzed using algebra – the consequence of which went on to inspire both the theory of relativity and quantum theory in the twentieth century.

You might also remember using the beginning of the alphabet (a, b, c) to represent known quantities, and letters at the end of the alphabet (especially x, y, z) to represent the unknown quantities. It was Descartes’ who inscribed this language into mathematics.

At the age of 24, Descartes left the military in 1620 and sold his estate he’d inherited from his mother, using the proceeds to finance his continued dedication to independent studies. From 1629 to 1633, Descartes worked tirelessly on his treatise* Le Monde ou Traité de la lumière*, which detailed his ideas on physics. Unfortunately, in a seemingly knee-jerk reaction, Descartes stopped publication immediately upon hearing news of Galileo’s trial for heresy as he was convicted for Copernican beliefs. Luckily Descartes was later able to recycle much of his work in different projects.

*The Method*, published in 1637, which covered meteorology, optics and geometry. Perhaps most profound about this particular work was that it was one of the first essays that attempted to explain meteorology with science and not with the tales of higher beings. While a man of God, Descartes showed us that life and the world around us can be understood through science – all the Earth’s inhabitants obeying laws of which can be determined through experimentation and keen observation. These observations, along with the thoughts and studies of Francis Bacon, laid the groundwork for the scientific method we know today.