A Specimen of Theory Construction from Quantum Gravity

Abstract

Despite the philosophical tone of this volume, I personally am much more of a working scientist than a philosopher. Of course it is good to remember Peter Bergmann’s description of the physicist as “in many respects a philosopher in worker’s clothes”, but it is not my purpose here to attempt to draw philosophical lessons from the history of work on quantum gravity. Instead I will only try to recount a certain part of my own experience with this problem, explaining how I arrived at the idea of what I will call a causal set. This and similar structures have been proposed more than once as discrete replacements for spacetime. My excuse for not also explaining how others arrived at essentially the same idea’ is naturally that my case is the only one I can hope to reconstruct with even minimal accuracy.