July 20, 2008 | Graham

Pascal’s wager and Sunday truths

One of the most commonplace arguments in support of action on global warming is a variant on Pascal’s wager. Pascal’s wager is the proposition that one ought to believe in God, because the detriment in not believing is so immeasurably larger than the cost of believing that one would be foolish not to take out insurance.
The adaptation of this to global warming is that the potential consequences of doing nothing are so horrendous that it makes sense to do something, just in case.
It is not one of Pascal’s better ideas, and one that most people would instinctively reject. Let’s do a thought experiment. How many of those advancing this as a reason for taking whatever their preferred action is on global warming actually believe in God? I’m not sure, but if they don’t believe in God, then you can discount their sincerity in advancing this argument. If it applies, it must apply in all comparable circumstances, and as this is the circumstance in which it was first advanced, it must be a comparable one.
But inconsistency is not the only argument against it. Pascal’s wager condenses all the possibilities down to a binary situation. There either is a God, or there is not, and there is only one God. As Don Aitken points out it is not that simple. As there are various claimants to the true God, then one would have to believe in all of them to have adequate protection, but a number of their truth claims are exclusive, so you can’t believe in all of them simultaneously without violating the basis on which some of them must exist.
The same problem exists with global warming where a number of claims of likley outcomes are made, only one of which can be true, and the identity of this outcome can only be assessed by us now on the basis of probabilities, which must include in the calculations the prospect that it is better to do nothing, and can’t proceed on a binary basis.
That’s not how the debate proceeds. Instead, proponents of action dream-up worst case scenarios and then demand action because of what might happen if action doesn’t occur, even though the probability of what they are advocating occurring is certainly lower than the probability of a real hell existing, and still lower than the business as usual situation delivering a superior outcome.
This is just another guise for the “precautionary principle” which works on the basis of trying to avoid one potentially bad outcome without anlaysing the prospects that other less bad outcomes will actually be more likely to occur.
It is also the basis for Ian Lowe’s bizarre proposition that we need a “sustainability science” where instead of the scientific method (which he brands as the “traditional” scientific method) which works on the basis of testing hypotheses via experimentation, we should assume a particular outcome and work backwards from that.
He dresses it up to sound respectable:

So we have to accept that our engagement with complex natural systems can’t be based on the old model for rational objective science. The traditional sequential steps will have to become parallel functions of social learning, and they’ll also have to incorporate the elements of action, adaptive management, and policy as experiment. Sustainability science needs to employ new methods, perhaps semi-quantitative modelling of qualitative data and case studies, or inverse approaches that work backwards from undesirable consequences to identify pathways that avoid those outcomes. Scientists and practitioners have to work together to produce trustworthy knowledge that combines scientific excellence with social relevance.

but it is in fact anything but science, and anything but respectable
In fact, it is the obverse of the coin-flip of Pascal’s wager. Just as Pascal’s wager dresses up religion in the language of probability, “sustainability” science dresses up religion in the language of science.

Posted by Graham at 10:26 pm | Comments (9) |
Filed under: Environment


  1. Well, I’m glad you mentioned the precautionary principle.
    That’s not voodoo, it is based on probabilities and above all, evidence.
    And all the evidence is that something very drastic is happening to our climate. Of course, this might be part of natural changes, which have happened previously and rapidly in the past. But all the evidence is that our species won’t be able to adapt quickly enough.
    And Ian Lowe’s argument isn’t dressing up science as religion. Rather, he is placing science in its proper social, economic and political context.
    Unless we can work out, with some semblance of democratic process, where we want to go (and it isn’t in the direction of Zimbabwe) then we have little chance of getting there.
    All the evidence points to a perfect storm of environmental disaster, and pointing out the obvious, that we need to direct our scientific efforts as clearly as we do our economic (but misguided) growth efforts, is hardly heretical.
    All this is fogged by the extremely high standards of living, food, etc that many of us enjoy. But on this planet, the Australian middle class is a privileged elite. We have achieved so much, but it has been hard fought and now the gap between classes is expanding. Ian is arguing for participation above all, and warning that complacency is the most dangerous stance of all.
    Maybe I need to be posting more evidence and less opinion in my blogspace.

    Comment by ronda jambe — July 21, 2008 @ 7:46 am

  2. There seems to be a strand running through all the AGW sceptic’s discourse at the moment that all proponents of AGW action are to be equated with religious zealots. This would appear to be a desperate ad hominem attack by a body largely bereft of any capacity for rational argument.

    Comment by Patrick B — July 21, 2008 @ 10:05 am

  3. Does no one see the irony of the Pope moving around in a bullet proof pope-mobile, surrounded by platoons of police and private body-guards? Surely this high-level representative of “the one true god” doesn’t need such protection. After all, shouldn’t his god’s might be enough to keep him from harm? And, if it isn’t, logically, wouldn’t that mean that his god had called him to heaven and wouldn’t that be welcome to him? – Clearly, the Pope neither welcomes a quick trip to heaven nor believes that his ‘maker’ can prevent it.
    If ever one needed convincing that religion is a fantasy for the feeble minded then this irony ought to be enough. What a tragedy that otherwise intelligent people still persist in promoting primitive superstition as though it had merit in today’s world.
    After all, if the Pope doesn’t believe it, why should any of you?

    Comment by Roger Hawcroft — July 21, 2008 @ 2:55 pm

  4. Ronda, I disagree that the precautionary principle is built on an assessment of risks, at least the way that it is used. For example, I’ve heard it used to justify opposition to nuclear energy, but when I’ve seen the risks analysed, nuclear is about as risky as coal-fired power.
    Seems to me that the precautionary principle is a bit of jargon used to justify avoiding a particular risk without any concern to properly analyse the risk of alternative courses of action.
    Patrick B, how can my comments on “Sustainability Science” be “ad hominem”? Are we not allowed to criticise anyone anymore? By jumping to conclusions and then acting on the basis that they may be right, and neglecting to test using rigorous logical methods, then you have moved outside of science and into some sort of realm of faith. This isn’t an AGW argument, it’s a methodoligical and epistemological one.

    Comment by Graham Young — July 22, 2008 @ 9:03 am

  5. Dr David Evans worked for the Dept of Climate Change from 1999 to 2005.Dr Evans used to believe that it was 90% certain that CO2 was the prime driver of perceived AGW.He now says that there is only a 20% probability that CO2 is the prime driver of temps or even that there is AGW actually happening at all.”When the facts change I change my mind.What do you do sir?”
    The computer models used by the IPCC are virtually useless.They cannot cope with the millions of variables which affect climate, nor are the people imputing the information aware of the subtle influences beyond the realm of their knowledge.
    Undisputed relevant facts;The ice cores have now revealed that CO2 levels rise behind temp increases by some 800 yrs.CO2 is a minor GW gas.Dr Evans suggests that the heating of the oceans release the CO2 thus the delay in atmospheric CO2.
    Temps across the planet in both the oceans and atmosphere have fallen since 1998 by 0.6 deg C while CO2 output has accelerated.
    See; http://www.lavoisier.com.au/papers/articles/DavidEvanswager.html
    “Why I bet against Global Warming”He explains it very simply.
    Would you insure against the non existence of God?

    Comment by Arjay — July 22, 2008 @ 7:59 pm

  6. The left have moved on from Communism to this new Greenism. They have seen communism fail as a way to bring everyone down to the same level around the world. So now they want us all to live like those in the third world, with small carbon footprints and not much affluence, as a way to stop us consuming and having an affluent lifestyle, all at the lowest common denominator.
    Rudd seems keen to help them do this, as do the media.
    Roger, regarding off topic on the Pope, he is a head of state so the Australian government would feel responsible to see that he is well protected. The position of the Pope is one of the few in the world that has actually had a nearly successful assassination attempt in the last 40 years, as well as at least two other attempts that were foiled. The Pope is also one of the few world leaders that makes himself seen by so many of his congregation. When did Rudd last appear in front of 500,000 people?
    If Catholics didn’t protect the Pope and he kept getting knocked off you would say we didn’t respect him and we should at least give him some security.
    The many Catholic maters over the years have shown that they are more than ready to die for their belief and meet their maker. Just read some of their stories. More Catholics were persecuted, tortured, and martyred last century than in any previous century, so they aren’t going away.

    Comment by Joe — July 25, 2008 @ 10:17 am

  7. Pascal’s wager is a shockingly baaaaaaaad analogy Graham.
    The flaw in Pascal’s wager is that there are many deities. Given you can only choose one, which one should you believe in? Jehovah, Allah, Zeus, or Thor?
    What if you choose wrong?
    We only have one climate. The precautionary principle is perfectly applicable. Do-nothing is not.

    Comment by JM — July 25, 2008 @ 11:36 pm

  8. Pascal’s wager is a shockingly baaaaaaaad analogy Graham.
    The flaw in Pascal’s wager is that there are many deities. Given you can only choose one, which one should you believe in? Jehovah, Allah, Zeus, or Thor?
    What if you choose wrong?
    However, unlike deities, we only have one climate. The precautionary principle is perfectly applicable. Do-nothing is not.

    Comment by JM — July 26, 2008 @ 2:48 am

  9. JM, I think I should return the compliment. That’s an appaling analysis of Pascal’s wager in terms of climate change. There isn’t an issue of belief in climate, but belief that the change will be cataclysmic, or is significantly caused by CO2. That’s a question to which there are a number of possible answers.

    Comment by Graham Young — July 26, 2008 @ 1:07 pm

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