Bohr's First Theories of the Atom

Abstract

When confronted with a case in which an accepted theory appears to fail, the physicist, like anyone else, has a choice of strategies. The most obvious, which is also that recommended by armchair methodologists, is to invent an entirely new theory; an example might be Johannes Kepler's system of planetary motions. The most likely strategy, because it involves the least reconstruction, is to seek the slightest departure from received ideas that will save the phenomena; an example is John Couch Adams's supposition of the existence of a distant planet to account for irregularities in the motions of Uranus. In both of the examples the strategies worked: Kepler's system, transformed by Newton, became the basis of the world of classical physics; Adams's calculations, and those of his French contemporary Urbain J. J. Leverrier, led to the discovery of Neptune.