The human mind is possibly the only thing in existence that lives separated from reality. Everything below the human state, below here meaning of more restricted consciousness, is embedded in the wholeness of life, more specifically natural life with its priorities of self-preservation and reproduction. Everything above the human state, such as angels and those human beings who have entered the kingdom of God, has become one with spiritual reality. There are also demons but these are a fallen not a natural category. It is only human beings who, by virtue of what they are, live outside reality. This is because human beings have moved beyond necessity into freedom but are not yet so far beyond necessity that they are fully free. They have developed a conscious self but are still bound to that because they have not yet aligned that self with the greater whole.
The human state is in many ways a sad state but it is one full of potential. It is sad because of the separation from the rest of life a conscious self causes with the inevitable consequence of suffering. Alienation is the hallmark of a human being, especially one that has progressed to the midway point we now occupy in which we have largely overcome pure instinct to live in a rational state but have not yet developed the intuition that would start us on the path of return to God. This is midway on the path of spiritual evolution but it is also the nadir of an arc, the point from which we have to ascend by turning to spiritual life. If we fail to do that, as so many of us are currently failing to do, we will fall still further into spiritual darkness.
It is only the human being who requires proof of God because it is only the human being that lives outside God, separated from him. The animal is unconsciously one with God, the saint consciously so. But all we know is our self, our own consciousness, limited in content and with a seemingly impenetrable barrier between it and everything else. And yet while our consciousness certainly is limited it is also self-conscious and in that fact is the source of freedom, love and potentially inexhaustible creativity. It is, in other words, god-like even if it is so in a very undeveloped form.
Do you want proof of God? The fact that you are a living, conscious being, no mere automaton, is proof that God is. He is in you. Not only in you, of course, but he is there, manifesting in your consciousness. You, you yourself, are proof of God.