"I believe that there is, from the ethical point of view, no symmetry between suffering and happiness, or between pain and pleasure. Both the greatest happiness principle of the Utilitarians and Kant's principle, "Promote other people's happiness...", seem to me (at least in their formulations) fundamentally wrong in this point, which is, however, not one for rational argument. [...] In my opinion [...] human suffering makes a direct moral appeal for help, while there is no similar call to increase the happiness of a man who is doing well anyway."
January 1, 1970
https://en.wikiquote.org/wiki/Negative_utilitarianism