Isn't there a Borges story about someone who discovers a multivolume book on eternity, only to realize that it is infinitely long? If not, there should be.
In the meantime, we'll have to be satisfied with two much shorter books, each tackling eternity from an opposite end. Carlos Eire's A Very Brief History of Eternity has a look at the significance of the idea of eternity in the West. Michael Hanlon's Eternity: Our Next Billion Years offers predictions for what will happen to us and our world over the next little while.
Eire, a history and religious studies professor at Yale, admits that eternity is an appallingly big subject. Rather than write philosophy or physics, however, he is interested in the concept of eternity. His thesis is that the idea had a major influence on the development of Western civilization and on the everyday lives of millions of people.
- Reviewed here: Eternity: Our Next Billion Years, by Michael Hanlon; A Very Brief History of Eternity, by Carlos Eire
Eternity can be conceived in a number of ways. One meaning of eternity is simply time without beginning or end. This is known technically as "sempiternity." (The funny thing about this eternity is that you can divide it into two halves, a past eternity and a future eternity; both are still eternity.)
The second idea of eternity is of a state that somehow transcends time. It might be a state that is completely separate from time, an eternity that contains nothing but one great big now. Or it might be a state that transcends time but also contains time within itself.
Eternity was important for early Christians to sort out, as they struggled to merge ideas on time and eternity taken from Greek philosophy with ideas they had inherited from Jewish teachings. Both had to somehow fit with the idea of salvation and a heavenly kingdom to come.
In fact, an important fourth-century theological battle hinged on eternity. A group of Christians called the Arians believed that God the Father had existed for all eternity, but that Jesus had a definite beginning. The opposing side believed that the entire Trinity (Father, Son and Holy Spirit) was eternal. This debate, believe it or not, was a hugely divisive issue for the early church. The latter camp won, banished their opponents and became Christian orthodoxy.
By the time of the Middle Ages, eternity had come to be seen not only as a concept about time or its absence, but also as a place and a condition. Eternity was where God was, and where humans would end up when they died.
Christian ritual constantly allowed eternity to merge into the ordinary temporal world. The ritual of mass, in which Christ's body and blood were consumed again and again, blended normal time with an eternity in which the Crucifixion was perpetually occurring.
Likewise, the medieval custom of burying the dead in churchyards (or even inside the church), and the veneration of relics such as the finger bones of martyrs, caused people to brush up against and think about the eternal in their everyday lives.
The eternal even hit people in the pocketbooks. Church teaching was that the worst people would suffer an eternity in Hell, the best would go straight to an eternity in Heaven, and most people would have to serve a term of perhaps millions of years in Purgatory before being allowed into Heaven. But paying for masses or for indulgences could shorten the time you or even a deceased loved one had to spend in Purgatory.
In 1517, a Dominican named Johann Tetzel was travelling around Saxony, offering indulgences for anyone who would donate to the building of a new basilica at St. Peter's in Rome. He was a man who knew how to make a sales pitch:
"Listen to the voices of your dead relatives and friends, beseeching you and saying, 'Pity us, pity us. We are in dire torment …'"
An Augustinian monk named Martin Luther was appalled by Tetzel's hard sell and began a movement that became the Protestant Reformation. Protestantism pushed eternity out of everyday life - no more masses, relics or bodies buried in the church - making it a matter between God and each individual.
Today, many people are less certain about eternity, or at least about eternal life after death. Eire sees this as a mixed blessing. A belief in eternity can lead to suicide bombers, he says. Disbelief can lead to death camps. Regardless, eternity has become a personal matter, to be grappled with alone.
"I don't know about you, but I'm outraged by a universe that exists eternally, but only allows me a scrap of time," Eire says.
Michael Hanlon's Eternity is ultimately no cheerier, dealing as it does with the ultimate death of the planet Earth. But it's entertainingly written, so that's something.
Hanlon, the science editor of Britain's Daily Mail, isn't really interested in eternity, as is clear from the subtitle of his book. (After all, a billion years is no more eternity than are a few seconds. That's the thing about eternity. It dwarfs everything.) Instead, he wants to explore some near and not-so-near possible futures for humanity and the planet.
At its best, Hanlon's book offers the fascination and sense of wonder of good science fiction. At its worst, it reads like an earnest United Nations report on the challenges to be overcome in the 21st century. Luckily, there's more best than worst here.
The good news is that humanity will probably survive the next few centuries. Neither dwindling oil supplies, nor global warming, nor even nuclear war, will likely be enough to destroy us as a species, and might not even destroy our advanced technological civilization. (Hanlon gives civilization a 50-50 chance over the next century or two.)
But things will be bad enough. By the middle of the century, world population will reach nine billion, before levelling off. Food and energy will become scarce. Poverty and unrest will increase. The U.S. government and economy might collapse. Europe will be under pressure from billions of desperately poor Africans. It's a grim picture, but not a surprising one.
Hanlon's more speculative ideas are more interesting. What if computers become self-aware? Will we have to grant them "human" rights? Is a time right around the corner when we can upload our consciousness into a machine and live forever? What would happen if we discovered intelligent life elsewhere in the universe? What if we found out we are alone?
Much of this speculation is presented in the form of science-fiction vignettes. For instance, in 2064, the supercomputers of the World Meteorological Office become self-aware and take over the world, turning off the electricity and sending humanity back into the Stone Age. Eventually, the computers are worshipped as gods. In another vignette, we discover that self-replicating machines from another galaxy are heading our way, destroying everything in their path.
In a more realistic vein, Hanlon takes us a billion years into the future, when a hotter sun evaporates enough water to spark runaway greenhouse gas warming. Temperatures eventually exceed 100 degrees Celsius, the oceans boil away, and all life ceases.
And what happened to us? Hanlon's not sure: Maybe we were destroyed long before, maybe we colonized the galaxy, maybe we became some sort of pure mind. But clearly, in a billion years nothing like modern humanity will be around.
Reading these books requires you to think about time on a scale that makes the head spin and the stomach drop. Inevitably, you consider the briefness of life and the inevitability of your own death. Your history, human history, the history of the Earth itself, seem insignificant when set against the vastness of never-ending time. Such thinking can be rewarding. But after reading both books, I've decided that eternity is best considered a little bit at a time.
Kurt Kleiner is a freelance writer specializing in science and technology. He contemplates his own mortality from Toronto.