To learn to make one's way about in the world it is of course necessary to rely on one's own observations and on the reports of other observers. But making one's way about in the world is also very much a matter of learning non-natural distinctions. These express attitudes and feelings which are normal and established in the community. Ownership is the most obvious example. The difference between Mine and Yours cannot be observed but it can be learned: and part of what is learned is Don't touch. It is this distinction which transforms territories and commodities into properties. All distinctions of this group I call ‘prosaic’. They are, or profess to be, wholly useful and business-like. Their importance lies entirely in their functional utility. They are all eminently reasonable and arguable—as important and as prosaic as a bank balance or a shop-steward.