you can look at physical things, and the physical forces that move them, and understand them in their own physical way. that is what science does. that is the beginning and end of knowledge as knowledge. everything beyond that can only be felt and experienced, never in an objective physical sense can the non-physical be honestly said to be known. that is why when religions do this, however well intended they mean to be, they are misleading. its not that there isn't more then is knowledge. its just that what isn't knowledge, isn't knowledge. there is the tao, and it exists, but to imagine anything about it, that it has a name or that its a god or anything else, like if there's a hierarchy of invisible things or any of that, every attempt to approach by that manor, only takes us further away. accept that you don't know what you don't know, and it is right there. the buddhists say there is no self and no other, and in that they are not completely wrong, but they are still putting words. their attempt to explain is noble, but it is still an attempt to explain.