A common objection to Nietzsche’s thought is that he went mad. This is often dismissed because Nietzsche is high status and the fact he went mad is just a commonly known fact about him, so that anyone who advocates for Nietzsche will be immediately shot down with the response: “He was mad though, wasn’t he?” (insert comment about syphilis). As it happens, this common-sense objection to Nietzscheanism is sound; he did go mad—people who go mad cannot be trusted to think soundly (even before it sets in). Ironically, this conforms to Nietzsche’s own philosophy—he celebrated the wisdom of the body, so that we should take his own body into account if we are Nietzscheans.
When you read Ecce Homo (or “eccentric homo”, as autocorrect divination has it) it seems very funny at first: Nietzsche says things like “why I am so great”, “why I am so brilliant”, “why I am so wise”—it seems uproariously funny to see a serious philosopher or a serious writer, people we all know to be motivated by a certain vanity, confess to what they really think themselves to be. The problem is that Nietzsche did not do so with an ironic edge; he didn’t write these things to then laugh at himself and say, “Well, we all think that about ourselves on one day or another.” No, he was deadly serious in that very Teutonic way—he, Friedrich Nietzsche, was the next Christ, the next Buddha, the next Mohammad. This was a serious business.
When he composed his last works, Nietzsche reported to a friend that he now understood what mystics meant when they said “some thing writes through me, I don’t write it—it writes itself”. As an atheist, Nietzsche scoffed at that—even though his own philosophy, with the evocative statement “not I but the wind that blows through me”, suggests this position itself. What “thing” blows through you once you negate the ego?
The contemporary materialist explanation, the one Nietzsche would endorse, says that when you practice any skill to a certain degree it becomes automatic—you enter “flow state”. Hence, to take a common example, when you first learn to drive you are conscious as regards everything in the car—you think about every act, every gear change. After a while, your brain makes all this automatic: you get in the car and “just drive”—you are not even conscious that you drive. A similar state pertains to piano-playing and language acquisition—native speakers “just speak it”, language learners pick over every phrase, and if you practice long enough language becomes automatic too. Hence masters in a craft put in “effortless” performances—just sit down at the chessboard or piano and go.
So if you write a book, it can feel like “the book writes you”—a “thing”, the unconscious process, writes through you and you never even think consciously about what to write; and this simulates “spiritual possession”—some “thing”, some daemon, dictates to you what to say and you, the human, are merely the transcriber, the amanuensis for the spirit world. So when Nietzsche reached a certain stage in his writing career—he was knocking out books at quite a rate after his retirement from university teaching—he became “possessed”. So goes the materialist explanation.
Given that Nietzsche had prophetic dreams as a child where he saw his dead father rise from the grave and claim his younger brother who shortly thereafter died, the alternative explanation is that Nietzsche himself was possessed by a spirit—and that the spirit eventually drove him mad, having first convinced him that he was the greatest figure since Christ (and better than Buddha, and Mohammad, and, well, everyone else). The facts fit with a demonic possession; and Nietzsche’s observations that he had started to “write like a mystic”, to carry out automatic writing, and that there was a “presence” within him that was separate from him conform with demonic possession—as do his radically blasphemous statements.