Chapter one talks a little about God. It says the invisible things of God are to be perceived and understood by the things that are made. Therefore, we can get a glimpse of the invisible through that which is visible. Verse 21 says however, because of this [necessary method and possibly the only way of understanding the invisible things of God], we become foolish and confused in our understanding of things. When we recognize the powerful things of God in the visible things, we need to realize it is ONLY A REPRESENTATION of the invisible things of God. Verse 22, thinking "what" we see is actually seeing God, we come foolish. When we do this, verse 23 says the understanding of the non-perishable God (invisible God) becomes erroneously changed into the image of a perishable man (visible man), and other physical creatures. Verse 23 implies that when we worship God and envision him as or like a physical man (creature), it is not the truth but a LIE. These verses imply God is not a physical man, or any other creature for that matter. The physical creatures are simply a representation of the invisible things of God. The visible is simply the means we have to understand the invisible [God].
By these few verses we know of what the things of God are not. By the process of elimination, can we determine what God is?