Simply by reading this sentence you have proved that you are a most exceptional human being. First, you are probably Canadian, which alone makes you a standout amongst the human race. Second, you certainly belong to the elite that reads Books in Canada. So you can congratulate yourself that you belong to a very select social cadre.
But doesn't this rare good fortune surprise you? Should you not be more humble, and reflect that among human beings you are really rather mediocre? Of course this is the correct attitude. Your physical characteristics, your blood group, your body temperature, the gases you pass from your anus, are human, all too human. That is how you should more properly think.
But then, a more ennobling vision may warm your heart. Every human being who stands, as we do, upon the threshold of the Third Millennium, belongs to a uniquely chosen band of brave pioneers. The human race is bursting with strength and knowledge. Soon we shall be able to overcome even our basest passions, and with our rich prowess in the physical sciences, we must surely be permitted to look forward to, not hundreds, but thousands, and millions perhaps, of generations of people like us, who are destined to populate the Solar System and shed glory upon the whole cosmos. We are the lucky few who have managed to get in on The Ground Floor of the Greatest Enterprise under Heaven: The Human Project.
John Leslie, professor of philosophy in the University of Guelph, would urge you to take a more cautious view. In The End of the World, he argues that it is more reasonable to adopt the viewpoint of mediocrity. Copernicus demoted the Earth from its mediaeval starring role at the centre of the universe to that of a diminutive member of the planetary chorus surrounding the Sun. Later astronomical discoveries carried Copernicus's depressing principle to even greater extremes of the unremarkable. The glorious Sun is now seen to be a provincial sparkle in that glowing conurbation of stars, the Milky Way, and this in its turn becomes a mote amongst the glittering network of galaxies and clusters of galaxies that extends all the way to-no-one knows where. The full extent of the cosmos has not yet been disclosed to us.
Pushing the principle of mediocrity as far as it can possibly go, Dr. Leslie arrives at a surprising result. We cannot even consider ourselves to be a members of a privileged subset of the whole human race. Let's take "the whole human race" to mean every human being who has ever lived and died, plus those of us alive today, plus those who will have been born by the time humanity becomes extinct. We want to determine how special we are to be alive now, at the start of the Third Millennium.
The impressions we get from historians and from the futurists beguile us into believing we may be very special people indeed. The rosier scenarios make it seem possible that the human race, in some form or another, will continue for thousands of generations, perhaps even millions, and that our descendants will spread throughout the cosmos. This prospect would make us, today, perhaps only 0.001 per cent, or even less, of all human beings who will actually have been born. That's very special, and so probably the human race may survive for millions if not billions of years.
But now let's look at some current numbers. These suggest that a total of about 78 billion human beings have lived since archaic homo sapiens first emerged, perhaps 600 thousand years ago. Since around 6 billion people are alive today, near the start of the Third Millennium, we the living make up 1/13th, or nearly 8 per cent of all the human beings who have ever lived. Does that make us special? Somewhat special. At no other time in the future is it likely that as many as 8 percent of humanity will be living all at the same time. This suggests to John Leslie that the human story may meet its end surprisingly soon.
The Princeton cosmologist Richard Gott uses the same Copernican principle as John Leslie, but applies a different statistical argument. Gott agrees that we should assume we are a random population of the middling kind, but contends that our possible variations from the average must follow a well-known mathematical law. On this law our probable futures can be calculated as a relatively simple function of our past. Plugging humanity's estimated life history of 600,000 years into Gott's formula we find there's a 95 percent chance that human life will survive no more than 15,000 years longer, and the same chance that it will become extinct 24,000,000 years from now. But if you take our current population explosion into account, human life would be likely to disappear in only twelve years. Doomsday may come sooner than we think.
It may seem odd that these sombre estimates can be made with confidence on the basis of a mere probabilistic formula. But this view is an outgrowth of the anthropic principle, which was first put forward by the British cosmologist Brandon Carter in 1974. The anthropic principle limits Copernican modesty by claiming privilege for intelligent observers (not necessarily human ones). Such minds can exist only in a universe physically capable of supporting them. Thus the mere fact that we are intelligent observers limits our lives to a type of universe in which "our" kind of physics and chemistry can operate. That means, among other things, that the universe must be at least as old as it is, or else we would not be here to see it.
In 1980, a time of world-ranging nuclear missiles, Carter applied this anthropic method in a more narrow sense, asking about human life in particular. Where was a human being most likely to find himself within the temporal spread of the whole species? Would he be more likely to find himself in an early period of the species, when people were few, or in a later period, when there would have been immensely many? Modesty would propose that one finds oneself in the larger crowd rather than the smaller. That puts one's place in history closer to the grim point of extinction of the species, rather than to the exciting start of everything. The fact of nuclear submarines on the prowl would lead us to judge ourselves as living close to the end. Carter never published his thoughts, but they reached John Leslie through the academic rumour channels. Leslie reconstructed the arguments and published them in 1989.
The immediate response of skeptics, learned and otherwise, to the Doomsday argument is almost always "Rubbish!" But let us consider that in 1980, when Brandon Carter first mulled over these thoughts, the acronym AIDS had yet to be invented. News of the Ebola virus had not yet reached the public. We lived under a nuclear threat, true, but how far has that actually lessened? Since the Gulf War, bacteriological warfare has now become a strong threat, especially from small and backward nations. The Ozone Hole now threatens us, along with global warming. And we have become almost certain that the dinosaurs were destroyed by an asteroid, and that we could meet the same fate. We should not rest too securely in the belief that the Leslie-Carter hypothesis is nothing but a mere abstract mathematical manipulation.
John Leslie's terse manner of writing does not make The End of the World altogether easy reading. But that perhaps puts an onus on the reader to peruse the book even more carefully. It surely absolves Leslie and his editors from the charge that he is promoting alarmist thinking for monetary gain. Perhaps we should be encouraged by the mere fact that The End of the World has indeed been published and is being widely discussed. That alone should shift our expectations in a more optimistic direction. The end of the human world has now been moved from the status of a flimsy eschatological fantasy into the world of logic, numbers, and possibilities for intelligent action. 

Richard Lubbock is a Toronto writer who has recently become a stand-up comedian.