A Modern Cartesian Demon

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During a throwaway thought experiment in his 1641 treatise, Meditations on First Philosophy in which the existence of God and the immortality of the soul are demonstrated, René Descartes posited the idea of an evil genius or demon that systematically deceives us to distort our understanding of the world. Contrary to first year philosophy students everywhere (a younger version of myself included), Descartes did not actually believe in the existence of an evil manipulator that was holding us back from understanding the nature of the real world. Instead, he was using it as part of a larger project to radically re-conceive epistemology in an era of rapid advancements in science that was threatening to overturn centuries of our understanding of the world. He felt that knowledge was built upon shaky ground thanks to an over-adherence on the received authorities from Greek antiquity and the Church’s use of Aristotelian scholasticism. Similar to Francis Bacon twenty years earlier, Descartes set out to focus on knowledge that stood independent of received authority.

Through Meditations one and two of his book, Descartes considers the sources of our beliefs and considers how we come to know what we think we know. He wants to find an unshakable truth to build all knowledge from, and through an exercise of radical doubt he calls into question many of the core facts we hold – first that knowledge gained from the senses are often in error, that we often can’t distinguish the real from fantasy, and through the use of the evil genius, that perhaps even our abstract knowledge like mathematics could be an illusion.

André Hatala [e.a.] (1997) De eeuw van Rembrandt, Bruxelles: Crédit communal de Belgique, ISBN 2-908388-32-4.

When I teach this to first year students, they either don’t take his concerns seriously because of the force of the impressions the real world gives us in providing sense data for knowledge (a stubbed toe in the dark seems to forcefully prove to us that the external world to our senses is very real), or they take Descartes too seriously and think Descartes really thought that a demon was actively deceiving him. Regardless of which side the student falls on, they will then conclude that Descartes’ concerns are not worth worrying about; that this mode of thinking is the product of an earlier, less sophisticated age.

Unless you are a scholar delving into Descartes’ work, the real purpose of teaching the Meditations is to provide students with a framework to understand how one can go about thinking through complex philosophical problems. Descartes starts from a position of epistemic doubt, and decided to run with it in a thought experiment to see where it took him. The thought experiment is a useful exercise to run your students through to get them to think through their received opinions and held-dogmas.

However, in light of my rant a few weeks back about informed consent and vaccines, I’ve discovered a new contemporary use for thinking about Descartes’ evil genius. In some sense, the evil genius is *real* and takes the form of fear that shortcuts our abilities to learn about the world and revise our held beliefs. Descartes posited that the evil demon was able to put ideas into our heads that made us believe things that were completely against logic. The demon was able to strip away the world beyond the senses and even cast doubt on abstract concepts like mathematics.

Much in the same way Descartes’ demon was able to “deceive” him into believing things that were contrary to the nature of reality, our fear of the unknown and of future harm can cause us to hold beliefs that do not map onto facts about the world. Worse yet, the story we tell about those facts can get warped, and new explanations can be given to account for what we are seeing. This becomes the breeding ground for conspiracy thinking, the backfire effect, and entrenched adherence to one’s beliefs. We hate to be wrong, and so we bend over backwards to contort our understanding of the facts to hold-fast to our worldview.

In truth, we are all susceptible to Descartes’ demon, especially those whom believe themselves to be above these kinds of faults of logic. In psychology, it’s called the Dunning-Kruger effect, of which there are all sorts of reasons given why people overestimate their competence. But in the context of an entrenched worldview that is susceptible to fear of the unknown lurks Descartes’ Demon, ready to pounce upon us with false beliefs about the world. Its call is strong, its grip is tight, and the demon is there to lull us into tribalism. We fight against those we see as merchants of un-truth and in a twisted sense of irony, the weapons of truth we yield only affect those already on our side, while those we seek to attack are left unaffected. It becomes a dog-whistle that calls on those who already think and believe as we do.

If we hope to combat this modern Cartesian demon, we’ll need to find a new way of reaching those we see on the other side.

Stay Awesome,


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