One of the more profound aspects of the first chapter was the emphasis placed on sound over sight.  God is so often represented as a voice, such as "in the beginning was the Word", or the many times people in the old and new testaments can hear the voice of the Lord, but can not see him, or at least can not see him clearly.  I was struck by the way the first chapter mentioned that we can easily and even reflexively close our eyes to keep out images, but have far more difficulty keeping sounds out of our ears.  Anatomically, we seem designed to hear without modulation, but can choose what we see, or indeed if we see anything at all.  It gave me new perspective on the tradition of closing one's eyes during prayer, and praying aloud.  Closing your eyes immediately places you at a disadvantage:  being deprived of your primary sense causes a marked change in your awareness of what you are hearing.  Perhaps that is the point of the tradition?