You never believed in the meaning of this world, and you therefore deduced the idea that everything was equivalent and that good and evil could be defined according to one’s wishes. You supposed that in the absence of any human or divine code the only values were those of the animal world – in other words, violence and cunning. Hence you concluded that man was negligible and that his soul could be killed, that in the maddest of histories the only pursuit for the individual was the adventure of power and his only morality, the realism of conquests. And, to tell the truth, I, believing I thought as you did, saw no valid argument to answer you except a fierce love of justice which, after all, seemed to me as unreasonable as the most sudden passion.
Where lay the difference? Simply that you readily accepted despair and I never yielded to it. Simply that you saw the injustice of our condition to the point of being willing to add to it, whereas it seemed to me that man must exalt justice in order to fight against eternal injustice, create happiness in order to protest against the universe of unhappiness. Because you turned your despair into intoxication, because you freed yourself from it by making a principle of it, you were willing to destroy man’s works and fight him in order to add to his basic misery. Meanwhile, refusing to accept that despair and that tortured world, I merely wanted men to rediscover their solidarity in order to wage war against their revolting fate. I continue to believe that this world has no ultimate meaning. But I know that something in it has a meaning and that is man, because he is the only creature to insist on having one. This world has at least the truth of man, and our task is to provide its justification against fate itself. And if it has no justification but man; hence he must be saved if we want to save the idea we have of life. With your scornful smile you will ask me: what do you mean by saving man? And with all my being I shout to you that I mean not mutilating him and yet giving a chance to the justice that man alone can conceive.

Albert Camus, “Letter to a German Friend #4,” 1944. In Resistance, Rebellion, and Death.