Ah yes, “Reason”. As in the Age of Reason. History in hindsight calls it the Reign of Terror. It ends with a guillotine.
The Age of Reason started over a hundred years before France's Reign of Terror. Descartes, Newton and Locke are examples of the age's thinkers. Following that was the Age of Enlightenment, with the likes of Montesquieu, Hobbes and our Founding Fathers. That was said to have ended with the French Revolution and its Reign of Terror.