Thoughts on the True Estimation of Living Forces

Thoughts on the True Estimation of Living Forces (German: Gedanken von der wahren Schätzung der lebendigen Kräfte) is Immanuel Kant's first published work.

Written in 1745–47 and published in 1749, it reflected Kant's position as a metaphysical dualist at the time. In it he argues against the vis motrix ("moving force") view supported by Wolff and other post-Leibnizian German rationalists that proposed that bodies have no essential force, and claimed that, instead, the existence of an essential force can be proven by metaphysical arguments. Kant criticized Leibniz's followers for looking "no further than the senses teach," and stayed close to Leibniz's original vis activa ("active force"; also known as vis viva, "living force") point of view.