Scientific Revolutions #3

The histories of science portrayed by Thomas Kuhn and Karl Popper -- according to their critics -- diverge from actual history. Parsons' counter-story follows.

"The history of science is not one of steady cumulative progress, but neither is it a succession of mutually exclusive paradigms where each new theory wipes the slate clean and starts all over again. If we regard all past theories as totally false, then the pessimistic metainduction probably should make us doubt our present theories, however empirically successful they are. But the history of science is not like the famous Peter Arno cartoon from the New Yorker: A test flight has just ended in a horrendous crash. The aircraft designer turns his back on the ensuing chaos, [and blithely says], "Well, back to the old drawing board." Science does not have to go back to the old drawing board with every superseded theory. Rather, when we look at the history of any field of science, a few theories will stand out as major breakthroughs. Once these breakthroughs occur, they are retained, in one form or another, through all subsequent theory changes, even through major conceptual revolutions. For instance, the mathematician and physicist James Clerk Maxwell (1831-1879) formulated a small set of simple equations that explained all the diverse phenomena of electricity and magnetism. He concluded that electricity and magnetism were different aspects of the same force, electromagnetism, and that light is actually a form of electromagnetic radiation. Maxwell's Treatise on Electricity and Magnetism was published in 1873, well before the two major revolutions in twentieth-century physics, relativity and quantum mechanics.
     The revolutions of twentieth-century physics overthrew some of Maxwell's ideas. For instance, he thought that since light was a wave, it had to be carried by some medium, the "luminiferous ether," an idea rejected by subsequent theory. However, light is still regarded as electromagnetic radiation, and Maxwell's equations, in modified form, are still regarded as valid for a given range of electrical and magnetic phenomena. Likewise, Newton's famous law of universal gravitation is retained in physics as correctly applying to things not moving too fast and to gravitational forces that are not too strong. So, many of Maxwell's ideas, like Newton's, have survived the enormous conceptual upheavals of the relativity and quantum revolutions, revolutions that overthrew so many of the ideas of "classical" physics. Within limited contexts, Maxwell's and Newton's theories are just as valid as they ever were. Other breakthrough theories have shown similar staying power in other fields of science" (p. 183-4).