"Our practical understanding of energy was greatly expanded during the 19th century thanks to the era’s proliferating experiments with combustion, heat, radiation, and motion. 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**.” But that, too, is still too Newtonian to be intuitive." ([Location 587](https://readwise.io/to_kindle?action=open&asin=B08SGC3TD3&location=587)) --- **Tags** -- [[quotes]], [[energy-conversion]], [[Isaac Newton]], [[joules]], [[physics]] **Source** -- [[202412030828 - B - How the World Really Works]]