There are people who argue that the only form of knowledge...
There are people who argue that the only form of knowledge available to humans is experientialknowledgeorexperimental knowledge, gained primarily by the use of outer senses. This led to the belief that human beings are constituted in such a way that the knowledge of reality is always unavailable to them; and so it resulted in a renewal of attention to the everyday world of appearances. The knowledge of here and now became the only object of human knowledge and concern.
Thus from this point of view, the project of seeking knowledge of reality behind appearances must be abandoned, because it is beyond the scope of human understanding. Now think: Can't there be a way of "being" [existing] that is not susceptible of being perceived by the limited capabilities of humans through their defective senses? I hope that the implications of the two expressions I used above ["limited capabilities" and "defective senses"] are evident to any thinking person.
The claim that something does not exist, because you haven't seen or heard it is untenable. When we consider the limitations of our sensual perception and of our reasoning powers, it is not necessary that we understand everything. We can speak meaningfully about everything simply on the basis of our perception. So to speak of "proof" with regard to a Transcendental Being becomes irrelevant.
What we can do is to point out facts which lead to a constant and inescapable awareness of the presence of God. It is clear that logically we can not rule out the possibility of more things existing than can be perceived by our senses or can be arrived at by our reasoning. As for Man, there are two dimensions to his existence: One of matter and the other of spirit. Reduced merely to the level of material existence, Man becomes a machine or a mere animal at best.
But think of a machine that rebels against being a machine; or of an animal that refuses to be an animal. That is what man is! What is it that makes him rebellious, angry, disappointed, frightened or hopeful? What is his dimension that gives him his imagination, his artistic genius, his creative urge? Why does he have nightmares and sweet dreams? It is not matter that does it; evidently it is his spirit that makes him so different from animals.
So to base our knowledge of the world and our philosophy of life simply on the material side of our existence to the complete exclusion of the spiritual dimension is undoubtedly faulty.