Lever a fixed point. The lever operates by applying forces at different distances from the fulcrum, or a pivot. Assuming the lever does not dissipate or store energy, the power into the lever must equal the power out of the lever. As the lever rotates around the fulcrum, points farther from this pivot move faster than points closer to the pivot. Therefore, a force applied to a point farther from the pivot must be less than the force located at a point closer in, because power is the product of force and velocity. If "a" and "b" are distances from the
Jan Lever by the Reformational philosophy of philosopher Herman Dooyeweerd. During his student days, Lever became acquainted with the biologist Johann Heinrich Diemer, who had published about Dooyeweerd's approach in the domain of biology in the 1930s. Diemer was a great influence on Lever's thought. Together with Dooyeweerd, Lever wrote four articles about the species concept in the journal "Philosophia Reformata" (1948–1950) in which species were defined as constant types. In his book, "Creatie en Evolutie" (1956), Lever still subscribed to Dooyeweerd’s philosophy but also suggested that it is possible that biological evolution occurred. Later he moved away from these earlier ideas