Descartes and the Age of Enlightenment

Scholars are unclear exactly when it was that the age of enlightenment commenced. If one were to listen to French philosophers we would believe that the age of enlightenment was ushered in with Rene-Descartes-Picture-Psychologistthe death knell of Louis XIV in 1715. Other historians would have the age commence around one hundred years prior in 1620 with the beginning of the scientific revolution. There are some scholars that mark the commencement of the Age of Enlightenment, or the Age of Reason, as it can also be known, with the publishing of Rene Descartes Discourse on Method in 1637. One of the primary contributions of the Discourse on Method was shifting the locus of knowledge from an external authoritarian model with Church and State being the arbiters of understanding to an internal locus of knowledge, where the mind was given freedom to question everything including God.

“I suppose therefore that all things I see are illusions; I believe that nothing has ever existed of everything my lying memory tells me. I think I have no senses. I believe that body, shape, extension, motion, location are functions. What is there then that can be taken as true? Perhaps only this one thing, that nothing at all is certain.” Rene Descartes

Beginning with the premise that nothing is certain and that to find certainty one must question everything Descartes laid a foundation of critical thinking that saw tremendous leaps in human comprehension of ourselves and the world around us.

Cogito Ergo Sum

“I think therefore I am” is possibly Rene Descartes most famous utterance and upon it hinges the quintessential psychological question: What is thinking these thoughts? Is it the brain, or is it the mind? Descartes was the foremost proponent of Cartesian Duality or substance dualism. Whilst Cartesian Dualism has its roots deep in Aristotelian philosophy it was Descartes who made the concept famous and bears his name in homage to the great man, where Cartesian roughly means ‘of Descartes’. In essence Cartesian Dualism states that the mind cannot exist outside of the body and that the body is incapable of thought. As the brain is one of the components of the body the philosophy here becomes murky and dense. The question of how an immaterial ‘substance’ can act upon a material one is a conundrum that has never been effectively unravelled.

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Renaissance Mechanism

It was toward the end of the renaissance that Descartes demonstrated one of the key aspects of his notion that the body was mechanistic. He dissected an ox’s eyeball and showed that an image was Workshop_of_Michiel_Jansz__van_Miereveldt_Elizabeth_Stuart_Queen_of_Bohemiaprojected on the retina through the pupil and lens. He used this as a proof that the body was nothing more than a machine, albeit an extraordinarily complex one. The body functioned on demonstrable laws of physics, whereas the mind or to be more precise, the psyche, was free of such material restrictions. The renaissance provided an era where the expansion of the mind and questioning of existence was encouraged amongst the nobility. Elizabeth, Princess of Bohemia was one such enquiring mind. She had been exhaustively tutored in the classics of philosophy and was well versed in rhetoric. She corresponded with Rene Descartes over seven years and provided a rigorous mind to hone his theories and explore substantial dualism. For more on this correspondence click here:


Bridging the Mind/Body Schism

It is perhaps ironic that the one of the most recently birthed sciences that of neuroscience, that could possibly have never existed if it were not for the Discourse on Method, is starting to prove that the purported gap between mind and body does not truly exist. In Descartes Error by Antonio Damasio explores the interrelationship between mind and body. To read Descartes Error please follow this link: In particular he looks at damaged brains and the reduced functionality of those who have suffered brain trauma. Damasio challenges the notions that the mind exists unfettered from the brain citing example after example of how the brain is a centre for reasoning thought and that:

“Reason may not be as pure as most of us think it is or wish it were…Emotions and feelings may not be intruders in the bastion of reason at all: they may be enmeshed in its networks for worse and for better.” – Antonio Damasio

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