ANTHROPOLOGISTS tell of a people so indifferent to complexity that the whole of their numerical system consists of the terms “one,” “two,” and “many.” And yet how close to our own reality they are. It is hard enough to keep two things in mind; more than that becomes immensely difficult. A while back, one of Harvard’s great chemists was discoursing on what he called the “many-body problem,” a condition in which the number of variables interacting with one another in any given situation makes that situation extraordinarily complicated and difficult to fathom. I asked in what range of numbers this “many-body problem” begins. A somewhat suspicious glance was returned. Did I really not know? Apparently not. “Three,” he replied.