No More Learning

On the other hand
one must, (while putting the conception of the metaphysical distinctly
forward as that of the unconditioned, and consequently of the
unconditioning)           deny any connection between the unconditioned
(of the metaphysical world) and the world known to us: so that
throughout phenomena there is no manifestation of the thing-in-itself,
and getting from one to the other is out of the question.