The century of light
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An entire century decided it had been living in the dark — and named itself after the light it thought it was letting in. That naming was itself an argument.
The Enlightenment (roughly 1680–1800) was not a school with a doctrine but a broad, pan-European movement — a shared mood and set of commitments that spread across borders and languages. Each language even gave it the same emblem: Aufklärung in Germany, lumières in France, Illuminismo in Italy, “enlightenment” in Britain. Everywhere, the metaphor was the same: light.
Underneath the local differences ran a family of shared values. The first and organizing one: reason as the tribunal of belief. No claim — of church, crown, custom, or ancient book — was to be accepted merely because it was old or authoritative. Every belief had to come before the court of reason and justify itself. Authority now had to answer to argument, not the other way round.
From that root grew the rest of the family. Nature is orderly, lawful, and knowable — no capricious magic, but a system open to inquiry (the lesson Newton had just taught). Progress: humankind is perfectible, history can improve, ignorance can be rolled back. Toleration in religion; individual liberty in life and thought. Secularization — a steady critique of “priestcraft,” superstition, and fanaticism. And humanity itself as a value: a cosmopolitan sense that reason and rights belong to all people, not one sect or nation.
Tying these together was a commitment to publicity and criticism — the conviction that ideas should be aired openly, debated in print and in public, and exposed to scrutiny rather than settled behind closed doors. Enlightenment is not just having reasons; it is submitting them to the light of public examination. (This is the seed of Kant’s famous demand for the public use of reason, which Unit 3 develops.)
Which single idea best captures the organizing commitment of the Enlightenment?
Now the metaphor, taken seriously. Light breaks through darkness — and the darkness is specific: ignorance, prejudice, unexamined custom, and unquestioned authority. To be enlightened is to see by your own reason rather than grope by inherited shadow. The image casts the reformer as someone letting daylight into a shuttered room.
The whole programme was compressed by Immanuel Kant into two Latin words borrowed from the Roman poet Horace: sapere aude — “dare to know,” or better, dare to use your own understanding. It is the Enlightenment’s motto because it makes the point that the obstacle is not a lack of intelligence but a lack of nerve. Kant makes this the heart of his 1784 essay, What is Enlightenment?.
What is the best reading of the phrase 'sapere aude' as Kant uses it?