Note 1152 — AN ESSAY ON MAN, IN FOUR EPISTLES (continued 3)
Reading edition
MS.:
Self-love the spring of action lends the force; Reason's comparing balance states the course: The primal impulse, and controlling weight To give the motion, and to regulate.
Bolingbroke, Fragment 3, says that "appetite and passion are the spring of human nature; reason the balance to control and regulate it." The image is borrowed from the works of the watch, where the spring is the moving power, and the balance regulates the motion.