The problem is one of opposition between subjective and objective points of view. There is a tendency to seek an objective account of everything before admitting its reality. But often what appears to a more subjective point of view cannot be accounted for in this way. So either the objective conception of the world is incomplete, or the subjective involves illusions that should be rejected.

"Subjective and Objective," in Mortal Questions, Cambridge University Press, 1979, p. 196.