Before winning his final post in philosophy at the University of Königsberg, Immanuel Kant was offered the position of professor of poetry in Berlin in 1764, which he turned down. Throughout his work, from his early observations on social habits and stories of ghosts to his final unfinished work full of notions about a priori matter, etymology, and recipes for the day, Kant always appears as a mind sorely tempted to go beyond what he viewed as “the boundaries of reason.” He was unrelentingly disciplined in the face of this temptation, but the nature of his temptation was revealing. Regarding spirits, for example, he said, “I confess that I am much inclined to affirm the existence of immaterial natures in the world, and to place my own soul in the class of these beings.” But soon after this comment he tempered his inclination, saying clearly that “the appeal to immaterial principles is the refuge of a lazy philosophy” (Dreams, II, 331).

While he was establishing the firm boundaries of his island of truth, Kant knew the temptations and the dangers of sailing far from the shores and into the fog, and so he was at times scathing in his rejoinders. In his early book Dreams of a Spirit Seer, a book written to refute the spiritualist claims of Swedenborg, who said he could see action from a distance, in far away cities, for example, Kant said that “the realm of shades is the Paradise of visionaries” (Dreams, II, 317).