Said Yeshayahu Leibowitz, because we are inside it. We can know, at most, about many things within the world.
Others agree. Here is what I found yesterday:
Pieper notes that there cannot be a closed system of philosophy and that any philosophy that claims to have discovered a “cosmic formula” is a pseudo-philosophy. [Pieper, Josef (2006), For the Love of Wisdom: Essays on the Nature of Philosophy, Ignatius Press].
In this he follows Kant, who rejected the postulation of a “highest principle” from which to develop Transcendental idealism, calling this pseudo-philosophy and mysticism. [Baur, Michael; Dahlstrom, Daniel O. (1999), The Emergence of German Idealism, CUA Press].