The following essay was written by AI and edited by Intellicurean.

René Descartes once promised a world rebuilt on certainty. Strip away all illusions, he said, and we might begin again—this time on solid ground. For centuries, he has been honored as a liberator of reason. But what if the revolution he sparked came not from clarity, but confusion?

In her recent Aeon essay, “The French Liar,” historian Sandrine Parageau reintroduces Descartes not as the serene founder of modern philosophy, but as a figure who provoked psychological vertigo in his readers and existential dread among his contemporaries. Rather than a clear-eyed rationalist, he appears here as an unsettling alchemist of doubt—one whose method seemed, to some, less like reason and more like manipulation.

A towering figure in intellectual history, Descartes (1596-1650) famously declared, “Cogito, ergo sum”—I think, therefore I am. His Discourse on the Method and Meditations on First Philosophy laid the groundwork for modern science, yet they also disoriented many of his peers. Parageau reveals that, far from being universally hailed, Descartes was condemned by some as a dangerous deceiver. These accusations, initially paradoxical against the architect of systematic reason, become, under Parageau’s scrutiny, a mirror reflecting the profound anxieties of a society on the cusp of modernity.

The Discomfort of Radical Doubt

With almost surgical precision, Descartes urged his readers to divest themselves of all prior opinions, prejudices, and “false knowledge”—to undergo what he called “hyperbolical doubt.” Only by demolishing inherited beliefs, he argued, could one rebuild on indubitable foundations. Parageau highlights how this radical intellectual purification, though meant to be temporary, was viewed by many 17th-century thinkers as dangerous. It wasn’t just a methodological reset; it felt like a descent into cognitive vertigo.

Recent scholarship has begun to echo this emotional reading of Cartesian skepticism. Jan Forsman, in his 2021 dissertation Of Dreams, Demons, and Whirlpools, contends that Descartes’s doubt was not merely a tool, but a lived, transformative experience meant to disorient before it could rebuild. His approach aligns with Parageau’s interpretation of Descartes not as a detached logician, but as a man whose method required emotional unmooring.

Christia Mercer, in her groundbreaking 2017 article “Descartes’ Debt to Teresa of Ávila,” suggests that Descartes may have borrowed from mystical traditions that emphasized introspective purgation—further embedding emotion into method. The Cartesian self, it turns out, may not have emerged from reason alone, but from something more elemental and uncertain.

The Accusation of Manipulation

One of the most vivid condemnations came from Meric Casaubon, who in a 1668 letter accused Descartes of constructing a philosophy that first annihilated belief, only to restore it through rhetorical domination. Casaubon accused Descartes of promoting ignorance as the pathway to the mysterious grandeur of the Cogito, dragging readers into despair before lifting them back with persuasive flair. “He casts down, and raises again, when they see cause,” Casaubon warned, likening Descartes to a puppet master of the intellect.

Parageau draws a chilling parallel between this 17th-century critique and the modern phenomenon of gaslighting—the psychological manipulation by which one is made to doubt their own sanity. Dutch theologian Martin Schoock was even more explicit in his 1643 Admirable Method, warning that Descartes’s system would lead to “mental disorder,” as it required “putting off the light of reason” and embracing ignorance. What Descartes called meditation, Schoock acidly dismissed as “doing nothing.”

For Casaubon and Schoock, the philosopher’s aim was not liberation, but domination. Descartes’s rigorous doubt appeared, from this angle, as an epistemic trap—a means to unmoor the mind only to reanchor it in his authority. It’s a startling idea: that the father of rationalism was seen by some as an emotional manipulator, wielding confusion as a tool of influence.

Religious and Intellectual Backlash

But such critiques were not merely philosophical. They were deeply rooted in the turbulent religious context of post-Reformation Europe. Descartes’s adversaries often likened his tactics to those of the Roman Catholic Church, which Protestants accused of maintaining clerical control through the suppression of lay understanding.

Parageau reminds us that these condemnations were colored by sectarian conflict. Casaubon aligned Descartes with both Puritans and Jesuits—groups seen as enemies by many Protestant intellectuals. The stakes were theological: Descartes’s critics feared his system lacked the means to support key Christian doctrines, like the soul’s immortality or the existence of God.

Steven Nadler, in recent lectures, has emphasized how Descartes’s method emerged in a time of crumbling metaphysical certainties and escalating religious anxiety. His dismantling of scholastic traditions felt, to many, like a spiritual as well as intellectual provocation.

Even those who admired Descartes’s scientific prowess were uneasy about his religious implications. As Parageau notes, English Protestants of the late 17th century often lauded his mechanics while warning against his metaphysics. His emphasis on method over received wisdom was viewed not merely as innovation, but as insurrection.

The Emotional Roots of Rationality

Here lies Parageau’s most powerful insight. Descartes, she argues, was not coldly analytical, but emotionally raw. His philosophy did not spring from dispassionate logic, but from crisis. As a young man, he discovered the teachings of his youth to be riddled with error. This epiphany caused what biographer Adrien Baillet called “violent agitations” and “psychological distress.”

Parageau, drawing on Tristan Dagron’s interpretation, connects this upheaval to a series of dreams Descartes experienced in 1619—dreams so disturbing that he later modeled his Meditations after them. These dreams blurred the boundaries between wakefulness and delusion, instilling a terror that would echo throughout his philosophical system.

Michel Foucault once argued, in Madness and Civilization, that Descartes expelled madness from the domain of reason. But new interpretations suggest otherwise. Instead of excluding madness, Descartes began from it. Forsman, Mercer, and others point to a method rooted in the very vulnerability it sought to overcome.

Susan James, in her work Passion and Action, has argued that Cartesian philosophy requires the management, not the elimination, of passion. The purification Descartes demanded was emotional as much as intellectual.

A Disquieting Foundation

Parageau concludes that Descartes’s critics were not entirely wrong: his philosophy did produce epistemic anxiety. But where they saw danger, she sees a more nuanced truth. Descartes embraced doubt, disorientation, even a kind of madness—not to harm, but to transform. His rational edifice was not built upon peace of mind, but upon its very rupture. In this, he resembles not a manipulator, but a figure more complex: part mystic, part surgeon, part exile from certainty.

We have long imagined Descartes as the calm architect of modernity. But as Parageau and recent scholars reveal, his foundations were laid atop psychological fault lines. The search for clarity began not with answers, but with tremors. And from that trembling ground, he built a system that still shapes how we think today.