It is not often that I find myself siding with Creationists. But on one thing at least, we all agree: Archbishop James Ussher's calculation of the date of Creation is no laughing matter. There we part company, however. I think Ussher's work was the height of 17th-century scientific sophistication, Creationists think its God's own truth.
Ussher, you may recall, was the archbishop of Armagh who, in 1650, famously announced that the world had been created in 4004 BC. A later refinement dated the event precisely to 9 a.m. on the morning of October 23rd in that year. This means that, if Ussher was right, next Saturday the world will be 6,007 years old. And on Thursday night in Trinity College, Dublin, a birthday lecture marks the occasion - about which, more anon.
Meanwhile Ussher, who was born in Dublin in 1581, has become something of a joke. But to those of you laughing at his work, I have only one thing to say: you try it! Modern geologists can use complex techniques to date a piece of rock. But transport them back to 1650, and they would find the only way of calculating an age for the Earth was to follow Ussher's technique and treat the Bible as an accurate historical record.
Like him, they would then sit down and spend several years carefully counting all the begats in the Old Testament, and worrying if all the patriarchs had been included. If, like him, they were thorough and conscientious, they would also study ancient Hebrew texts, analyse how ancient calendars were calculated, and correspond with astronomers to learn how Isaac Newton's new mechanics affected calculations of the length of a year.
Then, if they were any good, they should come up with a similar answer: the world beginning about 4,000 years before the Christian era. I would even put money on this. And how can I be so sure? Because dozens of other erudite scholars were doing the same thing around the same time and coming up with similar answers. There was even heated academic debate about whether time would have begun on the Saturday evening or the Sunday morning.
The only reason Ussher's calculation is remembered, rather than the Venerable Bede's, for instance (who thought the Creation happened in 3952 BC), or Isaac Newton's (who plumped for 3998 BC) is that in 1701 Ussher's chronology was chosen for the first notes to the authorised King James Bible. This became one of the most widely distributed books in the world, and Ussher's calculation attained a worldwide authority second only to the sacred scriptures themselves.
But if Ussher was right, then the world was relatively young, and there was not enough time for any slow geological processes to have taken place, and certainly no time for species to evolve. Instead, the Earth must have been created much as we see it today.
In the 19th century, increasing numbers of people questioned that view. So scientists sought other ways to calculate the Earth's age - based on the amount of salt that had accumulated in the oceans, for instance, or the time the Earth took to cool from a molten mass to a solid planet. And though most of these calculations were wrong, they did push back the age of the Earth to tens, hundreds and in some cases even thousands of millions of years. Now, thanks to radioactive techniques, most of us accept that the Earth is 4.6 billion years old, an age that leaves plenty of time for the relentless processes of geology and evolution to take place.
I cannot help wondering what James Ussher would have made of such a timescale. He seems to have had an open and inquiring mind, and used a telescope to verify for himself the theories of Galileo, Kepler and Copernicus. But would he have joined the Creationists? Perhaps Peter Costello knows. A writer and biographer with a passionate interest in Ussher, Costello is giving the anniversary lecture this Thursday night in TCD's Swift lecture theatre (7.30 p.m., admission €4). The venue is significant: Ussher was the second student to enrol at TCD, and his book collection later formed the nucleus of the college's world-famous library.
If you cannot attend the lecture, you can read about Ussher's calculations, including his analysis of dates in the ancient Irish annals, in an article by Dr Dan McCarthy, a TCD computer scientist who is fascinated by ancient Irish astronomy. It was published on the autumn equinox in 1997, making the 6,000th anniversary of Ussher's creation (Irish Astronomical Journal, volume 24, page 73, 1997).
Or why not read the original? Thanks to the Creationists, Ussher's work is still in print: last year, a new edition of his Annals of the World was published in the US in a fancy boxed edition, complete with CD-ROM.