Full Idea
It is far too little recognised how entirely the intellect is built up of practical interests. The theory of evolution is beginning to do very good service by its reduction of all mentality to the type of reflex action.
Gist of Idea
The mind has evolved entirely for practical interests, seen in our reflex actions
Source
William James (The Sentiment of Rationality [1882], p.34)
Book Reference
James,William: 'Selected Writings of William James', ed/tr. Bird,Graham [Everyman 1995], p.34
A Reaction
Hands evolved for manipulating tools end up playing the piano. Minds evolved for action can be afflicted with boredom. He's not wrong, but he is risking the etymological fallacy (origin = purpose). I take navigation to be the original purpose of mind.