Along the line's of Chris's Pascal's Wager analogy from a while ago:

'Catastrophe': Apocalypse When?
By PETER SINGER

Published: January 2, 2005

AN asteroid colliding with the earth could cause the extinction of our
species. Is this a risk worth worrying about? More important, is it a risk
worth doing something about? Richard A. Posner, a judge on the United
States Court of Appeals for the Seventh Circuit, who produces more books
in his leisure hours than most authors do working full time, thinks it is.

We should also, he argues, be doing more about other improbable
catastrophes. Global warming could cause the melting of icecaps, releasing
huge amounts of methane that accelerate further warming, forming a cloud
layer so dense as to block out heat from the sun and cause us to go into a
deep freeze. High-energy particle accelerators, used by physicists to
investigate the fundamental laws of nature, could produce particles that
create hyperdense ''strange matter'' that in turn might attract nearby
nuclei, thus growing larger and attracting ever more nuclei, until the
entire planet is compressed into a sphere no more than 100 meters in
diameter.

Not worried about these possibilities? Then what about the prospect of
bioterrorists genetically modifying an incurable strain of smallpox that
wipes out the human species? That might seem a more realistic scenario.

''Catastrophe'' lives up to its title. But it is no sci-fi potboiler, and
there will be no movie. Posner made his name defending an economically
rational approach to the law, and his new book is dense with complex
calculations of the expected costs of catastrophic events, and the amount
worth spending in attempts to avert them. The expected costs of a future
event are the costs of that event, if it should happen, divided by [danny:
multiplied by] the probability that it will happen. Thus, if I offer you
$1,000 if a tossed coin turns up heads, the expected cost of my offer is
$500. (Suppose I offer you $100,000 if a card drawn at random from a full
pack is the ace of spades. Would you prefer that offer to $1,000 tied to
the toss of the coin? Anyone interested in maximizing his assets would:
the expected cost of that offer to me -- and hence the expected value to
you -- is $1,923.) [danny: this sweeps under the rug the question of
utility for money. it's quite possible to rationally prefer the $1000
with .5 probability.]

When a catastrophe is really catastrophic -- and Posner, it should be
emphasized, isn't writing about ''minor'' disasters like the terrorist
attacks of 9/11 -- it can have a significant expected cost, even if the
event is extremely improbable. Consider, for example, the risk that a
high-energy particle accelerator will produce a ''strange matter''
disaster. The official risk-assessment team for one of these accelerators,
at the Brookhaven National Laboratory, offered a series of estimates, one
of which puts the annual risk of a disaster at one in five million. That
seems a very small risk. But since the disaster would kill six billion
people, that estimate gives it an expected cost of 1,200 lives per year.
Even if the risk is estimated more conservatively at one in a billion, it
has an expected annual cost of six lives. Would we build such an
accelerator if we knew that six people would die every year in which it
operates?

In the third and most difficult chapter of ''Catastrophe,'' Posner
explores ways of calculating the costs of catastrophic risks and of
possible responses to them. He rebuts the claim that it is not
cost-effective to do anything about global warming, an argument that
invariably relies on heavily discounting disasters that will not occur for
50 or 100 years. We may wish to invest money to generate wealth rather
than spending it to avert gradual global warming, but, as Posner suggests,
the victims of the warming are likely to be concentrated in poor countries
and will not necessarily benefit from the increased wealth generated by
the richer nations. (On the other hand, abrupt, spiraling global warming
that flips over into a deep freeze could kill us all, and then increased
wealth will not do us any good anyway.)

Any economic discussion of the expected cost of catastrophe must put a
dollar value on human life. Some will object to this in principle, but
unless we can agree on a figure, it will be impossible to decide what
expenditure is worth incurring, to build safer roads, say, or to keep
minute quantities of toxic chemicals out of our drinking water. Economists
working in this area usually investigate how much people are willing to
pay to reduce the risk of death -- for example, by buying safety devices
for their homes, or preferring to work in a safer occupation for a lower
wage than they could get in a high-risk occupation. The reduction in risk
is then multiplied by the sum the average person is willing to pay for it
to arrive at the value people implicitly place on their lives. Currently,
most government departments use a figure of around $5 million, give or
take a million or two.

One problem with this approach is that most of us assess large risks
differently from small ones. We may pay a steep price to reduce a risk of
one in a thousand to one in ten thousand, but we are not much concerned
about reducing a risk of one in a million to one in a billion. Yet a
rational person who is interested in continuing to live should be willing
to pay something for this reduction in risk. Clearly, these data show that
while people appear to be moderately competent at assessing large risks,
they are not very good at thinking about small risks. Posner, however,
mostly takes the data on their face, and suggests that the value of a
human life actually varies in accordance with the degree of risk we are
considering -- so that the loss of each human life in a highly improbable
catastrophe should be valued only at $50,000 instead of the $5 million
that it would be valued at if we were considering a more likely disaster.
This is bizarre. The real worth of our lives has nothing to do with the
probability of a particular cause of death.

IN short, Posner really has a much stronger case for saying we should
spend more to avert small risks of catastrophe than his own calculations
indicate. And the case gets stronger still if we take into account some of
the larger ethical issues he rapidly brushes aside, especially the
question of how we should view the fact that the extinction of our species
would prevent the existence of all future generations of human beings.
Barring catastrophe, our species may continue to exist for millions of
years, gradually overcoming our problems and achieving a level of
happiness, fulfillment and moral virtue -- including concern for the
well-being of other species -- that far exceeds anything we have yet
known. Arguably, this makes a catastrophe that causes our extinction a
much greater tragedy than the ''mere'' death of six billion people.

Posner's practical recommendations seem calculated to parcel out
irritation to everyone. Physicists will not like the doubts he casts on
particle accelerators. Liberals will be alarmed by his support for greater
police powers to counteract bioterrorism, including censorship of
scientific publications that could help terrorists devise new biological
weapons. Conservatives will dislike his support for taxes on carbon
dioxide emissions, and will be apoplectic at his proposal that we hand
over some of the nation's sovereign powers to an international
environmental protection agency to enforce an improved version of the
Kyoto Protocol on global warming.

As for ordinary readers, they will most likely be annoyed by the book's
frequent repetitiveness, particularly in the concluding chapter, and may
wonder what the two pages urging severe punishment for computer hackers
are doing in a book about catastrophes. (Did Posner lose part of his
manuscript to a computer virus?) Still, we would be well advised to set
aside such minor discontents and take the message of this book seriously.
We ignore it at (a small risk of) our (very great) peril.

Peter Singer is a professor of bioethics at Princeton University. His
recent books include ''One World'' and ''The President of Good and Evil:
The Ethics of George W. Bush.''

-- 
http://ai.eecs.umich.edu/people/dreeves  - -  google://"Daniel Reeves"