Jung is not performing humility here. He is describing a structural fact about the psyche: it exceeds the interpreter, every time, without exception. "Again and again" and "before each dream" are the key phrases — not a general disposition toward openness, but a repeated obligation, renewed at every threshold. You cannot bank prior understanding. The dream does not reward accumulated expertise by becoming more legible; if anything, experience increases the temptation to recognize, to slot the material into a known pattern, and it is precisely that temptation Jung names as what must be renounced.

What gets in the way is not stupidity but competence. The trained reader arrives with a repertoire — amplifications, motifs, parallels from alchemy and mythology — and the repertoire is genuinely useful until it becomes the thing the ego uses to stay ahead of what it cannot control. The preconceived idea is the mind's attempt to absorb the dream before it lands. Jung's prescription is simple and costs more than it sounds: let the dream be stranger than your knowledge of it. The ignorance he recommends is not passive. It is actively maintained against the pull of everything you already know.