EVEN ignorance seems to have a social hierarchy. For a philosopher to

be incapable of mending a tap is almost obligatory. A mathematician is

not expected to cut dovetail joints, or a classicist change a fuse.

Should colleagues become aware that they can, indeed, it might even harm

their career prospects. Yet academics are often the first to complain if

pupils display similar lack of knowledge about everyday life. The latest

cause for educational comment is a survey by Country Life magazine,

which found that 6% of pupils, including those at a prestigious public

school, think that turnips grow on trees. Similar surprise was expressed

some years ago when an even greater number were unaware that milk came

from cows.

We have some sympathy with the schoolchildren. There is no logical

connection between cartons of white liquid and a four-legged animal. The

process of depriving a cow of its calf, indeed, might cause considerable

outrage. Unless one examines a turnip carefully, its underground origins

are not obvious, any more than those of a peanut. Lack of knowledge on

such matters is evident in the Bounty advertisements, which show

coconuts falling from trees already shelled.

What is accepted knowledge in one generation, alas, soon becomes

useless in the next. We may eventually become aware, for instance, that

Sting and Madonna are singers, and suspect that Wet, Wet, Wet is

probably a pop group, but what they sound like we have no idea. We can

identify a Mozart opera immediately, but Boy George not at all. As

Vladimir Nabokov so wisely declared, we are sufficiently proud of

knowing something to be modest about not knowing everything.

All of us, fortunately, know someone more ignorant than ourselves,

even if it is the legendary Sam Goldwyn. ''We can't film The Well of

Loneliness,'' he was once told. ''It's about lesbians.'' ''OK,'' he

replied. ''So where they use lesbians, we'll use Austrians.''