KARL JASPERS FORUM

TARGET ARTICLE 63

QUITE A CHANCE OF DOOM SOON ?
(Review of OUR FINAL CENTURY by Martin Rees, 228 pp. Heinemann. £ 17.99. O 434 008 095) *
by John Leslie
1 August 2003*, posted 30 September 2003

[1]
"I think," writes Martin Rees, "the odds are no better than fifty-fifty that our present civilisation on Earth will survive to the end of the present century." Astronomer Royal and a world leader in cosmology, Sir Martin is known for not reaching conclusions hastily. Even if he is right, our species may have a much better than even chance of surviving the century. It might survive on Earth in uncivilised, Stone Age conditions. It might survive in extraterrestrial colonies. Still, he does give us rather strong reasons for setting up those colonies.

[2]
It isn't just human survival that is at stake. How easy was it for any life to evolve, let alone life of humanlike intelligence ? We can only guess wildly. Earth, Rees emphasizes, might be the one and only spot where intelligence has come into being. If it dies out here, the rest of the observable universe (of a billion trillion stars) may remain for ever devoid of it. Well written, well researched, fascinating, OUR FINAL CENTURY is above all an immensely important book.

[3]
Our galaxy contains tens of billions of stars much like the sun. Many of them, though, are billions of years older. Suppose intelligent beings had evolved on planets orbiting those more ancient stars. In just a few million years after attaining scientific competence, such beings could have made their presence felt throughout the galaxy. Why, then, do we see no signs that they exist ? A plausible answer is that scientific competence would have driven them to extinction quickly. Thanks to its competent scientists, Earth carries thousands of nuclear warheads and many other things that could be still more threatening. Millions of individuals, even, may soon acquire very frightening destructive capacities.

[4]
Consider all the ingenuity now applied to designing computer viruses. Then imagine such ingenuity put into developing some more easily communicable, more lethal version of the biological virus ebola --- which already kills up to 90 per cent of its victims. Ebola can be made, Rees remarks, with commercially available DNA. Many thousand microbiologists are skilled enough to make it.

[5]
Besides the threat of wickedness or irrationality in loners, in terrorist groups or in governments, there are the dangers of disastrous mistakes in academic or commercial experiments. Rees has bet a thousand dollars that "bioerror or bioterror" will kill a million people by the year 2020. Remember the Australian bioengineers of 2001, killing every infected mouse with a virus they'd designed with a view to mere contraception. And then ask yourself, perhaps, why anyone would design a contraceptive virus even when feeling rather confident that mice alone, not humans, would suffer its effects.

[6]
Instead of the "green scum" disaster of some biological experiment that went wrong, there could be a nanotechnological "grey goo" catastrophe. Towards the end of the century, Rees suggests, the risk of this will be more than science fiction. "Nanobots", microscopically small machines, might be able to reproduce themselves while feasting on all living matter. A week or two of that, and the biosphere could be dust. Or again, computers could develop superhuman intelligence by the middle of the century. Some say they should then be encouraged to replace the human race entirely. There could be a major ethical problem here, however: as Rees points out, superintelligence might be compatible with not being truly conscious.

[7]
Could we ban all potentially disastrous research? Well, Rees asks, without a police state in which everyone was spied on all the time, how could a ban be any more effective than the current war against drugs? And if evil or irrational people did the research covertly, how could the good and the rational know what defences to erect, had they failed to do such research themselves ?

[8]
Perhaps Doom Soon would take the form simply of a pollution crisis. Calamitous overheating might come, Rees argues, from a runaway greenhouse effect. Carbon dioxide is at present the main greenhouse gas apart from water vapour. Methane, though, may soon equal it in importance, and the warming that it caused would release yet more methane (plus more water vapour). Craig Venter, Rees tells us, plans to create strange new microbes for eating up the carbon dioxide. Problem minimized ? Maybe not. It strikes me that having too little carbon dioxide could be as awful as having too much of it. Plant life, too, needs this gas as something to eat ! Must we pray that Venter's carbon dioxide eaters are never released into the wild ?

[9]
Even a tiny probability of annihilating all intelligent life could be intolerable, given Rees's principle that the large or small chance of a disaster should be multiplied by the number of individuals who would be killed or who would never live at all -- for he thinks (rightly!) that people stranded in the realm of mere possibility, people never born because the human race became extinct too quickly, should also count for something. Again, a risk that at first appeared small could come to look large when seen through the magnifying glass of the "doomsday argument". This argument, to which Rees devotes a chapter, doesn't say that no efforts of ours can reduce the chances of disaster. What it does say, though, is that whatever risk estimates we arrive at, after taking account of whatever efforts we are making, could need to be revised pessimistically.

[10]
Originated by Brandon Carter, the doomsday argument is something for which Rees sees no easy refutation. It invites us to consider our place in the roll call of all humans who will ever have existed. Because of the recent population explosion, you and I live at the same time as about ten per cent of all humans so far. If the human race became extinct shortly, our place in the roll call wouldn't be too unusual. But what if humans colonized their entire galaxy ? You and I would then have lived among maybe the first hundred thousandth of all humans. Confidence in a long future for humankind, unless based on real success in reducing the risks that we face, could look altogether too implausible. It could look like supposing that, out of a hundred thousand intelligent species that will eventually have evolved in our universe, our species is the very first!

[11]
Rees's message is that the long-term prospects of intelligent life "may depend on us, this century". And, he points out, the main way in which we can do something about the matter, with maximum chances of success at minimum cost, is to set up bases on the moon and on Mars. From there, intelligent life could spread through the solar system. Whether or not it was destined to colonize the entire galaxy, its survival could be assured regardless of what happened on planet Earth.

[12]
It could be assured, that is to say, unless experiments at very high energies, perhaps a hundred times those reached by today's particle accelerators, created a tiny bubble which then expanded at almost the speed of light, consuming our entire galaxy for a start. In 1983 Rees helped to convince physicists that no all-destroying bubble could be born inside the accelerators of those days. He now stresses the need for caution as accelerator energies grow.

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[ NOTES : The discussed book by Martin Rees was also published in the United Stated, by Barnes and Noble, under the title OUR FINAL HOUR.

* The review by John Leslie was published in Times Literary Supplement, 1 August 2003, p.6, under the title "Return of the killer nanobots", and with a few other changes; it is posted here with permission the author and of TLS; paragraph numbers are added by me - HFJM ]

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Short biographical note:

John Leslie studied in Oxford and then taught Philosophy at the University of Guelph, taking early retirement in 1996 in order to get on with research and writing. Known mainly for work in philosophy of religion, philosophy of cosmology, applied ethics, and probability theory. Publications include the books Value and Existence, Universes, The End of the World, Infinite Minds (the most recent: Oxford Univ. Press, 2001), and the edited volume Modern Cosmology and Philosophy. University Prof. Emeritus at the University of Guelph, and Fellow of the Royal Society of Canada. The British Academy -- Royal Society of Canada Exchange Lecturer for 1998. Has been Visiting Prof. In the Research Dept of Philosophy, Australian National University, in the Dept of Religious Studies, University of Calgary, and in the Dept of Astrophysics, University of Liège.

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John Leslie