I've never read the whole piece before, so I was delighted to discover Dorothy L Sayers' 1947 essay The Lost Tools of Learning online. The web address for the copy I found is http://www.gbt.org/text/sayers.html, but I'm sure it's in lots of other places as well.
In a nutshell, but to vastly oversimplify, we used to know how to learn, and also use those tools to do some learning. Gradually, (over a few hundred years) Western civilisation was seduced by the sheer amount of learning we could do, to the point where stopped bothering with the how. Today, we are very rarely taught how to learn, with the consequence that people rarely see the knowledge they have as an integrated whole, and are rarely equipped to meet new challenges and situations. The result of this is beautifully (rhetorically) laid out in the essay's opening, where we have a string of examples from today's society.