We learn about “The Enlightenment” as a singular entity, a historical age associated with rationality, scientific inquiry, humanism, and liberty. The Enlightenment and scientific revolution were defining moments that spawned an unprecedented period of progress and human flourishing. But in his book The Beginning of Infinity, David Deutsch adds useful texture for better understanding the motivations of the Enlightenment’s contributors.

He divides the movement into two broad forms: the “British” and the “Continental”.

Both branches agree on the core principles of rationality, progress, and freedom. Where they disagree is on how to achieve these goals. They pursue the same ends,...