I cannot fall back on the resource of thinking myself under a moral necessity to regard all my duties as if they were commandments of God, although not entitled to hold speculatively that any such Supreme Being really exists. I am so far from feeling bound to believe for purposes of practice what I see no ground for holding as a speculative truth, that I cannot even conceive the state of mind which these words seem to describe, except as a momentary half-wilful irrationality, committed in a violent access of philosophic despair.

ME Book 4 Chapter 6 Section 5