Conviction is the belief that in some point of knowledge one possesses absolute truth. Such a belief presumes, then, that absolute truth exists; likewise, that the perfect methods for arriving at them have been found; finally, that every man who has convictions makes use of these perfect methods. All three assertions prove at once that the man of convictions is not the man of scientific thinking; he stands before us still in the age of theoretical innocence, a child, however grown-up he might be otherwise. But throughout thousands of years, people have lived in such childlike assumptions, and from out of them mankind’s mightiest sources of power have flowed.
The countless people who sacrificed themselves for their convictions thought they were doing it for absolute truth. All of them were wrong: probably no man has ever sacrificed himself for truth; at least the dogmatic expression of his belief will have been unscientific or half-scientific. But actually one wanted to be right because one thought he had to be right. To let his belief be torn from him meant perhaps to put his eternal happiness in question. With a matter of this extreme importance, the ‘will’ was all too audibly the intellect’s prompter. Every believer of every persuasion assumed he could not be refuted; if the counterarguments proved very strong, he could still malign reason in general and perhaps even raise as a banner of extreme fanaticism the ‘credo quia absurdum est.’1 it is not the struggle of opinions that has made history so violent, but rather the struggle of belief in opinions, that is, the struggle of convictions.
If only all those people who thought so highly of their convictions, who sacrificed all sorts of things to it and spared neither their honour, body nor life in its service, had devoted only half their strength to investigating by what right they clung to this or that conviction, how they arrived at it, then how peaceable the history of mankind would appear! How much more would be known! All the cruel scenes during the persecution of every kind of heretic would have been spared us for two reasons: first, because the inquisitors would above all have inquired within themselves, and got beyond the arrogant idea that they were defending the absolute truth; and second, because the heretics themselves would not have granted such poorly established tenets as those of all the sectarians and ‘orthodox’ any further attention, once they had investigated them.Nietzsche, Friedrich (1878) Man Alone With Himself (excerpts from ‘Human, All Too Human’)