It seems to me that understanding can only be achieved by looking at two things to compare one versus the other. In this we find either similarities or contrasts. It is from this basic framework of understanding that we observe our world and learn. We have come a long way from the day Adam first opened his eyes, but we are prone to error in the way we see things. Too often we believe that we can, and do, exist in ourselves. But how is that possible? Everything must exist because something else created it and sustains it. Sometimes you have to look down to the molecular level, but this is true of all things.
But what of things spiritual? Not surprising, we make the same mistakes here. We know we are made in God's image, but we do not know God. We know we are sinful, but we think too often we do not need a Saviour. Or at least that is how we lives our lives too often. We forget that we cannot exist without God. We forget that our natural yearning to seek a god is built into us by nature of our creation. On one hand we seem to be too flippant when considering things spiritual. It is the chief driver of the world, but how many days do we give it no thought at all. We think we are observing something (the world) when we are really observing something else (the spiritual). Perhaps if we viewed ourselves in relation to our God and Creator our perspective would get a bit clearer. Perhaps we need to realize on a more daily basis that apart from God we could not exist at all.
"Methinks that in looking at things spiritual, we are too much like oysters observing the sun through the water, and thinking that thick water the thinnest of air." - Herman Melville