I'm sure that many of you have had philosophy courses which have exposed you to these concepts, and you may accept this basic premise that there is no such entity as a Ding an sich whether or not we can perceive it. Yet we all tend to remain closet realists, and refute Bishop Berkeley, as Samuel Johnson did, by kicking the stone and feeling real pain. The more important question is, does it actually make any difference in our everyday work whether deep down we consider knowledge to be about some "real" world independent of us, or whether we consider knowledge to be of our own making? The answer is yes, it does make a difference, because of the first point I suggested above: in our profession our epistemological views dictate our pedagogic views.