Four things are necessary for empirical science to be possible (assuming that we believe that science is about the way the universe really is, and not merely about its appearances to us):
1. There must be scientists.
2. There must be a universe for scientists to understand.
3. The universe must have an intelligibility.
4. The scientists must have intellects capable of grasping the intelligibility of the universe.
These four propositions are assumed in the constitution of science; they are not anything science itself can discover because their truth is already assumed as soon as science happens. This is plainly obvious in assumptions #1 and #2. If a scientist embarked on a research program to discover if there are in fact scientists, or if there is in fact a universe, we would laugh at him, and laugh even more if he published his results in a respected journal confirming that there are, indeed, scientists and a universe. Our humor follows from the utter lack of self-awareness of the scientist in not knowing that his own existence proves all that can or needs to be proven.
The same considerations apply to assumptions #3 and #4, but for some reason many modern scientists (and some philosophers, who should know better) do not see it. They think that the mind is something that can be researched scientifically like anything else, and that conclusions like "the mind is essentially a model-maker" can be taken straightforwardly like any other scientific conclusion. But there is really just as much humor in this scientist as in the scientist who researches the existence of scientists, for science itself is only possible if the mind is something more than a mere model-maker.
The mind is ultimately invisible to pure empirical science because it is behind it as its subjective ground. But science needs an objective as well as a subjective ground. The objective ground of science is God, and like the subjective ground of science, the objective ground is invisible to science itself. As the mind is both behind and beyond science, so is God.
Just as many modern thinkers fail to get the point about the mind, they fail to get the point about God. They want to research God the way they research anything else, and demand "scientific evidence" of the existence of God, which is just as silly as demanding scientific evidence of the existence of scientists, except that it is humorous in the objective direction rather than the subjective. Either the universe itself and its basic intelligibility is sufficient evidence for the existence of God, or nothing is.
This is why the traditional arguments for the existence of God (neatly summarized in St. Thomas's Five Ways) are irrefutable yet seem insufficient to the modern mind. The Five Ways are arguments all made from the basic existence and intelligibility of the universe; that is, the way the universe must be known to be prior to the conduct of empirical science; the way the universe must be if science is to truly happen at all. We want to put God in the scientific court, when it is God who built and maintains the courthouse.
Immanuel Kant understood the significance of all this, which is why he is still among the greatest of modern philosophers. The basic program of modern philosophy (meaning philosophy since Descartes) is to find a way to undermine the legitimacy of traditional metaphysical philosophy (and its conclusions about God) while retaining the rationality of math and empirical science. Although propositions #1 and #2 are ultimately metaphysical in nature, they are immediately obvious and undeniable, and therefore acceptable to modern philosophy. But propositions #3 and #4 are not so immediately obvious, and in fact have been denied at various times in history. They are truly metaphysical claims. If we are not going to accept metaphysics, Kant saw, then we can't accept propositions #3 and #4, because they imply a metaphysical connection between the mind of man and the true nature of the universe. It may be (Kant thought) that the intelligibility of the universe is only something we read into the universe. And this fact, of course, is something that can never be verified or refuted by empirical science. If we are going to eliminate metaphysics, then the most we can say about science is that it is about the appearances of things (phenomena) rather than the way things truly are (noumena).
The mind ultimately knows itself in its own act, or it doesn't know itself at all; we know God through the universe in its basic act of existence and intelligibility, or we don't know God at all (excepting through revelation, of course.) Both the mind and God are known philosophically or they are not known at all.