Roy Porter sums up the miscalculations that lie behind our preparations for the Big Date
Questioning the Millennium: a rationalist's guide to a precisely arbitrary countdown

by Stephen Jay Gould

Jonathan Cape, pounds 12.99

The approach of the millennium elicits all those responses in Stephen Jay Gould which make him today's finest spokesman for the joys of science. The rationalist in him is horrified yet fascinated by the tradition of "Apocalypse soon" prophesies. Taking Christ's teachings literally, early Christians preached the end of the world was at hand; later doom- sayers predicted a whole diary of dates for the divine cataclysm. The year 1000 was, obviously, a favourite; 1666, the Number of the Beast, was later pencilled in, while the US Millerite sect put its money on 21 March 1843. When that year proved inexplicably peaceful, they turned into the Seventh Day Adventists, the largest modern body of Armageddon fanatics.

Towards all such groups, Gould has mixed feelings. He pities the wretched of the earth who have been so tragically deceived by false prophets. The native American Indians who joined the Ghost Dance movement in the 1870s believed not only that the Second Coming was nigh, but that they possessed bullet-proof shirts to protect them against the Devil in the guise of US cavalry. They were wrong on both counts, but no more than the Heaven's Gate cult, who committed mass suicide in the expectation of being whisked to heaven in the Hale-Bopp comet.

The millenarian prophets themselves leave Gould exasperated, yet he feels drawn to pay tribute to the scholarship, however fantastic, which has led them to calculate with such fastidiousness the timing of the Last Things. In 17th-century Britain, Archbishop Ussher computed that the world had begun at noon on 23 October 4004 BC. His projections then envisioned it ending on 23 October last year, for God had taken six days over Creation and hence would allot mankind a 6,000-year stay, seeing that "one day is with the Lord as a thousand years" (2 Peter 3:8).

Gould cannot avoid a sneaking sympathy for the godly numerologists who have calibrated Creation, for he recognises similar impulses in science itself. Civilisation presupposes calendars, and savants have always sought, if not to time the Apocalypse, at least to parcel up the grand cycles of Nature into years and months, hours and minutes.

Until the arrival of the quartz chip, calendrics depended upon astronomical observations of the great lights of the sky. Yet, while their regular orbits have made such measurement possible, they have also made it damnably frustrating. For the Earth, Moon and Sun are not in sync: no whole number of days makes a lunar month, no precise sum of months amounts to a solar year (365 days, 5 hours, 48 minutes, 45.96768 seconds). Hence the Julian calendar had to work in its leap years, while the reformed Gregorian calendar needed to "lose" 10 days and some of its leap years - now there is no leap year in century years except when divisible by 400, as in 2000!

Granted all these calendrical complexities, Gould is more than sympathetic to popular confusion as we face the millennium. Should the day of celebration be l January 2000, or 2001? Pedants deem the latter authentic. Yet, as so often, the professors turn out to be no more correct than the rest. For one thing, when the monk Dionysius Exiguus (Dennis the Short) first drew up the BC/AD date system fixed on Christ's birth, he left out Year Zero, so we're all one year out anyway. And, in any case, given that we now know Herod died in what we call 4 BC, then, assuming we can trust the Bible story of the massacre of the innocents, Christ must have been born some years before His official nativity. Thus, in a nutshell, all of us are wrong, and the most we can hope for is consistency within whatever artificial calendrical system we use.

This helps to explain why Gould feels such admiration for those prodigies who are masters of date-day puzzles. Mention the words "10 September, 1941" and, like Dustin Hoffmann in Rain Man, they can answer immediately: "a Wednesday". How do the minds of such idiots savants work? No one knows, and this is a particularly poignant puzzle for Gould because, as he reveals, his own eldest son possesses this astonishing gift, which comes with the curse of autism.

In Gould's eyes, the religious zealot, the professional scientist and the idiot savant are all attempting in their own ways to achieve the same thing. Merest specks of dust adrift in a boundless cosmos, we humans are drawn to discern its order, to take its measure, to fathom its meanings. What is clear from this splendid book - crisp, clever and chirpy as ever - is that Stephen Jay Gould will go down as one of the real turns of the century.