The process [by which any individual settles into new
opinions] is always the same. The individual has a stock
of old opinions already, but he meets a new experience
that puts them to a strain…. The result is an inward
trouble to which his mind till then had been a stranger, and
from which he seeks to escape by modifying his previous mass
of opinions. He saves as much of it as he can, for in this
matter of belief we are all extreme conservatives. So he
tries to change first this opinion, and then that (for they
resist change very variously), until at last some new idea
comes up which he can graft upon the ancient stock with a
minimum of disturbance of the latter, some idea that
mediates between the stock and the new experience and runs
them into one most felicitously and expediently.
¶ The new idea is then adopted as the true one. It preserves
the older stock of truths with a minimum of modification,
stretching them just enough to make them admit the novelty,
but conceiving that in ways as familiar as the case leaves
possible. (William James, Lectures on Pragmatism, 1907)