As William was pondering on a stone, Matthew asked him, "Where are your books? That light bequeath'd to beings else forlorn and blind." Matthew was wanting to know why he was wasting time, when he could be studying books. Matthew stressed the point that books were left by our ancestors for our learning. Matthew goes on to say, " You look round on your mother earth, as if she for no purpose bore you;" Clearly, Matthew is misinterpreting the situation. William is looking at mother earth with a purpose to learn. He finds that you can learn better by observing nature than reading another's thoughts on the subject. William is not accepting somebody else's word of knowledge, but he's discovering his own knowledge. I think of William as a symbol of individual thinking (a pioneer), and Matthew as a symbol of society's restriction because he chooses to restrain his knowledge to words on paper.
Next, WIlliam replies to Matthew. William makes the point that there are things we see that we should pay close attention to because there might be some spirit trying to communicate. In this case, nature is communicating. William says, "That nothing of itself will come, but we must still be seeking?" When nature is ready to teach us, then we better be listening already. Really I think that in the poem, there is a sense that nature is constantly teaching. It's just