Having already treated (see: Limen, Aprill and October 2008) Cusa's doctrine of human knowledge at the level of senses, reason and intellect; where each kind of knowledge is presupposed by the next higher one as its "higher cause", now in this article the author continues to explain Cusanus' epitomology at the highest level where is a moment of absoluteness in human knowledge, viz. the knowledge of God as the fundamental A priori of human thingking. This A priori cannot be denied without affirming it just by denying, because God as "ipsa absoluta praesuppositio omnium" necessarily must be thought , not only that we are able to think something else (in order to do this, the mere idea of God is sufficient, as is already shown by Immanuel Kant) but that we are able to think anyway. Since the manner of an empirical reality nor the way of a mere idea (for both are conditional ways of being), so the manner of being of God's reality can be only be a manner beyond all manners known by us. Also beyond a "highest idea" wherein our intellectus sees coincide all other things. Human knowledge of God is like an open horizon, an infinite framework. Only within this framework any human knowledge can occur. As such this knowledge "on principle" is still without content, like an empty frame, which is to be filled by the intellectus. In virtue of its coincidence perspective, the intellect is able via imagination and reasoning to bring the sensibilia, presented to the senses, back to thhe one and only Original, to the non-being origin of all beings. This Origin present itself in otherness in the many beings in an always unique way. The work of full-filinf or perfecting our "on principle" knowledge of God by research of the beings, will never come to an end because of the infinitude of the frame. The absolute truth or the final knowledge of God remains the unattainable ultimate object of our hunt for wisdom, as Nicholas of Cues calls philosophy.