Deism is the belief in one God who created the world and then left it alone to function according to natural laws discoverable by human reason. Unlike the God of the Old and New Testaments who, from time to time, intervenes in human affairs, the Deist God is remote, detached, and knowable only through His Creation. Deism, in short, is the religion of the Scientific Revolution and the Age of Enlightenment.

Like most major phenomena in the history of knowledge, the Scientific Revolution lacks firm chronological boundaries. It is generally thought to encompass parts of the 16th, 17th, and 18th centuries, highlighted by the work of Isaac Newton. The Scientific Revolution began with astronomical discoveries: Nicolaus Copernicus’s heliocentric universe, Galileo Galilei’s telescopic observations, Johannes Kepler’s laws of planetary motion, etc. These discoveries fueled Europe’s much broader 17th- and 18th-century Age of Enlightenment, when growing awareness of the laws of nature spread to the social and political realms, giving rise to ideas such as liberty, equality, and natural rights. Rooted in the free exercise of human reason, these historic intellectual movements exerted tremendous influence on Paine and other luminaries of his era.