Whenever convictions are not arrived at by direct contact with the world and the objects themselves, but indirectly through a critique of the opinions of others, the processes of thinking are impregnated with ressentiment. The establishment of criteria for testing the correctness of opinions then becomes the most important task. Genuine and fruitful criticism judges all opinions with reference to the object itself. Ressentiment criticism, on the contrary, accepts no object that has not stood the test of criticism

L. Coser, trans. (1973), pp. 67-68 - Das Ressentiment im Aufbau der Moralen (1912)