The Dreams of the Spirit-Seer was thus also a self-critique. He wrote Mendelssohn that to preempt mockery by others, he found it wisest to mock himself, which was honest and something he had to do because his mind “is really in conflict on this issue” (10:70.2–5). The problem, he explains, is the presence of the mind in the material world, and that analogies between spiritual and material substances are flights of fancy unhindered by data (10:71–2). With this admission, in the letter on April 8, 1766, before his forty-second birthday, the entire pre-critical project Kant had worked on since he was twenty had come to a crashing halt.