Alan Cromer

Uncommon Sense

The development of relativity and quantum mechanics in the first quarter of this century amazed the world of physics with new concepts and principles unimaginable in Newtonian mechanics. Does this make Newtonian mechanics just another tradition-bound system, more powerful than its predecessor but destined to be replaced by still more powerful systems in the future? This is the way it may have looked when these theories were new, but with the benefit of a little more historical distance it looks quite different.

First, relativity and quantum mechanics have stood the test of time, in spite of diligent efforts to find alternative formulations. Second, relativity and quantum mechanics never replaced Newtonian mechanics. Physics students study Newtonian mechanics as thoroughly as ever and, in addition, relativity and quantum mechanics. Without replacement, the developments of relativity and quantum mechanics don't meet Kuhn's own definition of revolutions as 'non-cumulative breaks.' Removing them from the list changes our whole perspective on science because we are then without a bona fide revolution for the last 150 years.

Although 150 years is short in terms of human history, it is a respectable fraction of the entire age of modern science. Seen from this perspective, we can change our metaphor from political upheavals to biological growth. The mistakes of the early days of science are, like the falls and bumps of a toddler, a nonrecurring phase of the growing-up process.

Science is overwhelmingly cumulative, not revolutionary, in its structure. This means that most of its established results—even those established recently—will be around forever. A particular result may be found to be an instance of a more general result, but its factualness, as far as it goes, will never change. Archimedes' principle of buoyancy is still taught today in much the same way as it was first stated 2,300 years ago, although we now derive it from more general principles. Indeed, most of Greek science and all of its mathematics are still as valid as ever. It is the physics of Aristotle that is anomalous.