This led to what is still the most common definition of energy: “the capacity for doing work”—a definition valid only when the term “work” means not only some invested labor but, as one of the leading physicists of the era put it, a generalized physical “act of producing a change of configuration in a system in opposition to a force which resists that change.”[29] But that, too, is still too Newtonian to be intuitive.
