The Enlightenment was an intellectual movement in the 1700s where people focused on nature and natural laws. Thinkers believed that everything had a cause and effect relationship and that humans were part of the natural world governed by discoverable rules. Isaac Newton's laws of physics inspired the desire to understand rules across nature. Rationalism held that truth could only be achieved through reason. Enlightenment thinkers, called philosophes, spread ideas through publishing, most notably the Encyclopedia, which criticized the church, government, and other institutions. While some faced imprisonment, their ideas spread and influenced revolutions.