"My reason is now all to me—my only warrant for God, virtue, and immortality. Woe to me if I catch this, my only witness, in a contradiction! if my esteem for its conclusions diminishes! if a broken vessel in my brain diverts its action! My happiness is henceforth intrusted to the harmonious action of my sensorium: woe to me if the strings of this instrument give a false note in the critical moments of my life—if my convictions vary with my pulsations!"