Unification and Revolution: A Paradigm for Paradigms

On the first of the two occasions I met Thomas Kuhn, we immediately plunged into a ferocious but very friendly argument about incommensurability. He was for it, I was against. Believing in incommensurability was Kuhn’s worst mistake. If it is to be found anywhere in science, it would be in theoretical physics. But revolutions in theoretical physics have one striking feature in common: they all embody theoretical unification. Revolutions associated with Galileo, Newton, Faraday and Maxwell, Einstein, Bohr, Schrödinger, Dirac, Tomonaga, Schwinger and Feynman, Weinberg and Salam, have all been unifying revolutions. Far from obliterating the idea that there is a persisting theoretical idea in physics, revolutions do just the opposite: they all actually exemplify the persisting idea of underlying unity. Furthermore, persistent acceptance of unifying theories in physics when empirically more successful disunified rivals can always be concocted means that physics makes a persistent implicit assumption concerning unity. To put it in Kuhnian terms, underlying unity is a paradigm for paradigms. Once this is recognized, it becomes clear that we need a new conception of science which represents problematic assumptions concerning the physical comprehensibility and knowability of the universe in the form of a hierarchy, these assumptions becoming less and less substantial and more and more such that their truth is required for science, or the pursuit of knowledge, to be possible at all, as one goes up the hierarchy. This view makes explicit that we can improve assumptions and associated methods – aims and methods – as we proceed with physics, and knowledge improves. There is something like positive feedback between improving knowledge, and improving aims and methods – the nub of scientific rationality, and the methodological key to the great success of science. This hierarchical conception of science has important Kuhnian features, but also differs dramatically from the view Kuhn expounds in his The Structure of Scientific Revolutions. I describe basic features of this hierarchical view, and give reasons why it should be accepted