I see it time after time in posts on this board where people bring a scientific mindset to the question regarding the existence of God. It's well and good to note that you can't see, touch, hear, etc. God in the same way you can physical substances, but if your epistemology on this issue is limited to the scientific method, you are asking the wrong questions.
The same is true regarding human existence. If you try to define love, for example, solely by resort to evolutionary processes, the movement of chemicals, etc., then you are missing something fundamental.
The problem I have with science in this regard is that it not only purports to answer these types of questions, but it purports to tell you it is the only way to look at things. From an existentialist standpoint, if given the choice between scientific materialism and mythological hocus pocus, I'd pick the latter every time.