Is philosophy like plumbing? I have made this comparison a number of times when I have wanted to stress that philosophising is not just grand and elegant and difficult, but is also needed. It is not optional. The idea has caused mild surprise, and has sometimes been thought rather undignified. The question of dignity is a very interesting one, and I shall come back to it at the end of this article. But first, I would like to work the comparison out a bit more fully.

Plumbing and philosophy are both activities that arise because elaborate cultures like ours have, beneath their surface, a fairly complex system which is usually unnoticed, but which sometimes goes wrong. In both cases, this can have serious consequences. Each system supplies vital needs for those who live above it. Each is hard to repair when it does go wrong, because neither of them was ever consciously planned as a whole. There have been many ambitious attempts to reshape both of them, but existing complications are usually too widespread to allow a completely new start.

Neither system ever had a single designer who knew exactly what needs it would have to meet. Instead, both have grown imperceptibly over the centuries, and are constantly being altered piecemeal to suit changing demands, as the ways of life above them have branched out. Both are therefore now very intricate.