Descartes stripped knowledge to the bone, imagining a trickster capable of forging every sensation. Yet the very act of doubt proved an unshakable truth: if one questions, one exists. That insight set the stage for modern reason.

In 1637, the French philosopher René Descartes wrote a sentence that would become one of the most famous declarations in the history of thought: 'Cogito, ergo sum' — 'I think, therefore I am.' It was not a statement of pride, but of survival. Descartes had stripped everything away — belief, sensation, even the physical world — in search of something that could not be doubted. What remained was the act of doubting itself. The mind, in motion. The awareness of thought. That flicker of self-recognition became his proof of existence. 'Cogito, ergo sum' is often misunderstood as cold logic, but at its core is something intimate and radical: the idea that consciousness is the foundation of being. That even if all else is illusion, the fact that we are asking, wondering, thinking — means we are. It is the root of the modern self, the turning point where philosophy shifted inward. In those three words, a new world emerged: one in which truth begins not in the heavens, but in the mind of the seeker.