Metaphysical world.- It is true, there could be a metaphysical world; the absolute possibility of it is hardly to be disputed. We behold all things through the human head and cannot cut off this head; while the question nonetheless remains what of the world would still be there if one had cut it off.
Friedrich Nietzsche, R. J. Hollingdale (1996). “Nietzsche: Human, All Too Human: A Book for Free Spirits”, p.15, Cambridge University Press