Metaphysics demands that we seek for the origin of existence beyond the conceptual categories with which we perceive and organise the world. This is what is meant by the failure of all positive metaphysical theories, that we must look elsewhere for a solution that works. This may seem a dry and dusty analytical observation of use only to scholastics but this is far from being the case.
It would be the philosophical approach required by any apophatic theology, and as such provides a logical foundation for this form of theism. It may be argued that this is not theism, and this would be my view, but it hardly matters one way or the other. There would an inconceivable phenomenon, call it what we will, that is our origin and existential foundation. About this phenomenon we can say nothing positive since to do so would be to mis-describe it. Thus it becomes indescribable, and with it the entire world. It then becomes possible to say with no provisos, ‘Words that are strictly true seem to be paradoxical’.
This is a conclusion that can be reached in discursive philosophy with or without reference to God. Here is Nicolas de Cusa showing us by the use of a theistic language that experiment and theory will lead us to the same place.
Apart from thee, Lord, naught can exist. If, then, Thine essence pervade all things, so also doth thy sight, which is Thine essence. For even as no created thing can escape from its own proper essence, so neither can it be from Thine essence, which giveth essential being to all beings. . . .
Accordingly, Thou, Lord, seest all things and each thing at one and the same time, and movest with all that move, and standest with them that stand. And because there be some that move while others stand, Thou, Lord, dost stand and move at the same time, at the same time Thou dost proceed and rest. For if both motion and rest can be individuated at the same time in diverse beings, and if nought can exist apart from Thee, and no motion be apart from Thee, nor any rest; then Thou, Lord, art wholly present to all these things, and to each, at one at the same time. And yet Thou dost not move nor rest, since Thou art exalted above all, and freed from all that can be conceived or named.
Wherefore, Thou standest and proceedest, and yet at the same time dost not stand or proceed. . . . Wherefore I observed how needful it is for me to enter into the darkness, and to admit the coincidence of opposites, beyond all the grasp of reason. and there seek the truth, where impossibility meeteth me. . . .
Wherefore I give Thee thanks, my God, because Thou makest plain to me that there is none other way of approaching Thee than that which to all men, even the most learned philosophers, seemeth utterly inaccessible and impossible. For Thou hast shown me that Thou canst not be seen elsewhere than where impossibility meeteth and faces me. Thou hast inspired me, Lord, who art the Food of the strong, to do violence to myself, because impossibility coincideth with necessity, and I have learnt that the place wherein Thou art found unveiled is girt round with the coincidence of contradictories, and this is the wall of Paradise wherein Thou dost abide. The door whereof is guarded by the most proud spirit of Reason, and, unless he be vanquished, the way in will not lie open. Thus ‘tis beyond the coincidence of contradictories that Thou mayest be seen, and nowhere this side thereof.
Nicolas of Cusa (b. 1401), The Vision of God