One must never have spared oneself, one must have acquired hardness as a habit to be cheerful and in good spirits in the midst of nothing but hard truths.
Most commonly revolt is born of material circumstances; but insurrection is always a moral phenomenon. Revolt is Masaniello, who led the Neapolitan insurgents in 1647; but insurrection is Spartacus. Insurrection is a thing of the spirit, revolt is a thing of the stomach.
One should not be deceived: great spirits are skeptics ... Strength, FREEDOM which is born of the strength and overstrength of the spirit, proves itself by skepticism. Men of conviction are not worthy of the least consideration in fundamental questions of value and disvalue. Convictions are prisons.