How the World Really Works: The Science Behind How We Got Here and Where We're Going

by Vaclav Smil

During the 1920s, following this fundamental insight of 19th- and early 20th-century physicists, the American mathematician and statistician Alfred Lotka concluded that those organisms that best capture the available energy hold the evolutionary advantage.[21]

These are: gravitational energy, kinetic energy, heat energy, elastic energy, electrical energy, chemical energy, radiant energy, nuclear energy, mass energy.”

is important to realize that in physics today, we have no knowledge of what energy is. We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. However, there are formulas for calculating some numerical quantity, and when we add it all together it gives . . . always the same number. It is an abstract thing in that it does not tell us the mechanism or the reasons for the various formulas.[30]