Numbers

REMEMBER the paperless office? And the jet-propelled back- pack for individual flying? How about instant home-shopping by computer? Ten years ago all of those, we were told, would happen 'within a decade'.

I blame President Kennedy. When he announced, in 1961, that the United States would have a man on the Moon 'by the end of the decade', and the boast was delivered, he introduced a pernicious catch phrase into the language of scientific speculation. Scanning the data base of serious newspapers since the beginning of June 1994, we find 1,115 uses of the phrase 'within a decade' or 'within the next 10 years'.

Moon-landings apart, such predictions have tended to be pure moonshine. 'Within the next 10 years' seems to mean: 'We have huge problems to overcome and haven't the faintest idea how we are going to tackle them.' At best 'within a decade' claims are based on an extrapolation of past progress. But future improvements have never been predictable from past achievements.

When a scientist says 'within five years', he usually knows what he is talking about. But 10 years is a dream. So, to take a few examples from the 1,115 most recent sightings: the black box recorder in cars, the discovery of hundreds of stars with planetary systems, the collapse of the Dutch flower market, 30 million deaths from tuberculosis and (once again) shopping becoming obsolete by 2004. As for the cattle egret that may colonise Britain 'within a decade or two', don't hold your breath.