To begin with, our knowledge grows in spots. The spots may be large or small, but the knowledge ever grows all over... What you first gain from them is probably a small amount of new information, a few new definitions, or distinctions, or points of view. But while these special ideas are being added, the rest of your knowledge stands still, and only gradually will you 'line up' your previous opinions with the novelties I am trying to instil, and modify to some slight degree their mass.