Physics, for example, has split into the sciences of astrophysics, thermodynamics, particle physics, quantum field theory, and many others. Each of these is based on a theoretical framework at least as rich as the whole of physics was a hundred years ago, and many are already fragmenting into sub-specializations. The more we discover, it seems, the further and more irrevocably we are propelled into the age of the specialist, and the more remote is that hypothetical ancient time when a single person’s understanding might have encompassed all that was understood.
