Tools for characterizing materials.

Abstract

“If you can spray them then they are real” is the philosopher of science Ian Hacking’s pithy answer to the question of when we should believe in the existence of those microscopic entities we cannot see. Much history and philosophy of science has concerned the second half of Hacking’s slogan. Historians have investigated how scientists came to believe that things like electrons, neutrons, and photons are real. Philosophers have wondered what it means to build science around the belief in entities that are unobservable, or only indirectly observable. But the first half of the quote hints at other, more rarely told stories. When we spray electrons, or neutrons, or photons, how do we spray them? At what? To what end? The history and philosophy of science have said a great deal about the things we spray, but much less about how and why we spray them…