The Second edition of "Either/Or" was published early in 1849. Later that year he published "The Sickness Unto Death", under the pseudonym Anti-Climacus. He's against Johannes Climacus who kept writing books about trying to understand Christianity. Here he says, "Let others admire and praise the person who pretends to comprehend Christianity. I regard it as a plain ethical task – perhaps requiring not a little self-denial in these speculative times, when all 'the others' are busy with comprehending-to admit that one is neither able nor supposed to comprehend it." Sickness unto death was a familiar phrase in Kierkegaard's earlier writings. This sickness is despair and for Kierkegaard despair is a sin. Despair is the impossibility of . Kierkegaard writes: