In my twenties I studied the history of Western philosophy; it is often told as a triumphant march of Reason. But in the mid-20th century, a famous intellectual skirmish broke out over what—or Who—was left behind on that march. The debate centered on a few pages of René Descartes’ Meditations, but it opened up a chasm between two of France’s greatest thinkers: Michel Foucault and Jacques Derrida.
At the heart of the conflict is a haunting question: Is "madness" a biological reality we’ve learned to treat, or is it a category we invented to keep "Reason" pure?
The Cartesian Doubt: Can the Thinker be Mad?
In his First Meditation, Descartes sets out to doubt everything to find a foundation for certainty. He wonders if his senses are deceiving him, acknowledging that people in "insane asylums" believe they are kings when they are poor. However, Descartes quickly brushes this aside. He argues that while he can doubt his senses, he cannot be "mad" because the very act of systematic, rational doubting requires a sane mind.
* Foucault’s Interpretation: In Madness and Civilization, Foucault argues this is a "judicial exile." By excluding the madman from the realm of thought, Descartes establishes Reason by forcefully ousting its opposite. Madness becomes an "error of omission"—a silence at the heart of the Enlightenment.
* Derrida’s Rebuttal: Derrida argued that Foucault misunderstood the text. For Derrida, Descartes didn't exile madness; he surpassed it by imagining an "Evil Genius" that could deceive even a sane mind. Reason doesn't lock madness out; it looks into the abyss and finds the Cogito ("I think") anyway.