Full Idea
Every philosopher whose initiative counts for anything in the evolution of thought has taken his stand on a sort of dumb conviction that the truth must lie in one direction rather than another, and a preliminary assurance that this can be made to work.
Gist of Idea
All good philosophers start from a dumb conviction about which truths can be revealed
Source
William James (The Sentiment of Rationality [1882], p.40)
Book Reference
James,William: 'Selected Writings of William James', ed/tr. Bird,Graham [Everyman 1995], p.40
A Reaction
I would refer to this as 'intuition', which I think of as reasons (probably good reasons) which cannot yet be articulated. Hence I like this idea very much, except for the word 'dumb'. It is more like a rational vision, yet to be filled in.