It is the certainty that they possess the truth that makes men cruel.
[C’est la certitude qu’ils tiennent la vérité qui rend les hommes cruels.]
Anatole France (1844-1924) French poet, journalist, novelist, Nobel Laureate [pseud. of Jaques-Anatole-François Thibault]
(Misquotation)
Widely attributed (in French and English) to Anatole France, but not found in his works, including the one location it is sometimes cited from, Les Dieux Ont Soif [The Gods Are Thirsty, The Gods Are Athirst, The Gods Will Have Blood] (1912), in either English translation or, more importantly, in the original French.
While thematically keeping in the novel's depiction of the French Revolution and the Terror, the closest match to the quote I can find is this portion of ch. 22, talking about the expediting of the trials of those charged with counter-revolutionary crimes, eliminating the need to prove a misdeed by simply inquiring as to the accused's beliefs.
Justice thus abbreviated satisfied them; the pace was quickened, and no obstacles were left to fret them. They limited themselves to an inquiry into the opinions of the accused, not conceiving it possible that anyone could think differently from themselves except in pure perversity. Believing themselves the exclusive possessors of truth, wisdom, the quintessence of good, they attributed to their opponents noting but error and evil. They felt themselves all-powerful; they envisaged God.
[tr. Allinson (1913), Jackson (1921)]
Justice, thus curtailed, satisfied them; the pace was quickened and no obstacles were left to confuse them. They confined themselves to inquiring into the opinions of the accused, not conceiving it possible that anyone, except from pure perversity, could think differently from themselves. Believing themselves to possess a monopoly of truth, wisdom and goodness, they attributed to their opponents all error, stupidity and evil. They felt themselves omnipotent: their eyes had seen God.
[tr. Davies (1979)]
La justice abrégée les contentait. Rien, dans sa marche accélérée, ne les troublait plus. Ils s’enquéraient seulement des opinions des accusés, ne concevant pas qu’on pût sans méchanceté penser autrement qu’eux. Comme ils croyaient posséder la vérité, la sagesse, le souverain bien, ils attribuaient à leurs adversaires l’erreur et le mal. Ils se sentaient forts : ils voyaient Dieu.
[Original]
