Black marks on white paper (otherwise known as a poem)

From Reflections on the Psalms by C.S. Lewis:

... For what is required, on all these levels alike, is not merely knowledge but a certain insight; getting the focus right. Those who can see in each of these instances only the lower will always be plausible. One who contended that a poem was nothing but black marks on white paper would be unanswerable if he addressed an audience who couldn't read. Look at it through microscopes, analyse the printer's ink and the paper, study it (in that way) as long as you like; you will never find something over and above all the products of analysis whereof you can say "This is the poem". Those who can read, however, will continue to say the poem exists.