"What traitors books can be! You think they’re backing you up, and then they turn on you. Others can use them, too, and there you are, lost in the middle of the moor, in a great welter of nouns and verbs and adjectives." (2.386)
Beatty misses the point. The reason books are valuable is because they are contradictory, conflicted, and confusing. It means that the reader can – or has to – think for himself, as Guy so desperately wants to himself.