One sort of madness consists in seeing the accidental (or contingent) as necessary. We meet someone and later think that the meeting was fated; it was written in the stars. In La Nausée (1938), Sartre explores this issue. Nothing is actually necessary; it’s all contingent. Everything that has happened could have happened differently—or not have happened at all. One’s own birth never had to happen. The world would have gone on fine if you were never born.
When the Nazis claimed to be “just following orders,” they were confusing the necessary with the contingent. What they did did not have to done; there were many other possibilities. Rank and file Nazis could have refused to carry out orders. They might have been shot, but they had a choice nonetheless. For Sartre, ethics does not consist in rule following, but rather in making “authentic” choices for which one is willing to suffer the consequences.
I think we can read a lot of European literature (and philosophy) beginning in the 1930s as a reaction against fascism. One prominent example is Finnegans Wake (1939), even though Joyce started writing it in about 1922. In this novel nearly every word has several possible meanings–there are few necessary meanings; however, this work is not just a clever linguistic exercise.
Personal relationships are accidental. In Iris Murdoch’s novel The Sea, the Sea (1978), the character James, who is thoroughly reasonably and sage-like, tells his irrational cousin Charles, a retired theater director, that most human relationships originate accidentally; there was nothing fated about a particular relationship. But Charles persists in making a sort of religion around his early relationship with Hartley, who becomes, in his mind, a saint and the end-all and be-all of his life. Charles can’t even see Hartley as her own person with her own thoughts and desires. She is just a component in a vast, preordained drama. The word “accident” occurs 32 times this novel.
The same pattern occurs in Murdoch’s The Black Prince (1973), as an older man becomes obsessed with the daughter of his close friends. These characters never even make a serious attempt to understand the person they claim to love. Another of Murdoch’s novels is titled An Accidental Man (1971); it too explores questions of accidents, fate, and morality.