Full Idea
Theories are instruments, not answers to enigmas, in which we can rest. We don't lie back upon them, we move forward, and, on occasion, make nature over again by their aid. Pragmatism unstiffens all our theories, limbers them up and sets each one to work.
Gist of Idea
Theories are practical tools for progress, not answers to enigmas
Source
William James (Pragmatism - eight lectures [1907], Lec 2)
Book Reference
James,William: 'Pragmatism - eight lectures' [Dover 1995], p.21
A Reaction
This follows his criticism of the quest for 'solving names' - big words that give bogus solutions to problems. James's view is not the same as 'instrumentalism', though he would probably sympathise with that view. The defines theories badly.