Full Idea
Physicists, ignorant and contemptuous of philosophy, have been content to assume their particles, points and instants in practice, while contending, with ironical politeness, that their concepts laid no claim to metaphysical validity.
Gist of Idea
Physicists accept particles, points and instants, while pretending they don't do metaphysics
Source
Bertrand Russell (Our Knowledge of the External World [1914], 4)
Book Reference
Russell,Bertrand: 'Our Knowledge of the External World' [Routledge 1993], p.131
A Reaction
Presumably physicists are allowed to wave their hands and utter the word 'instrumentalism', and then get on with the job. They just have to ensure they never speculate about what is being measured.