Friday, January 18, 2008

Wagering on the Future

The French mathematician Blaise Pascal suggested in his Pensees that believing in God is a better "bet" than not believing. This is Pascal's Wager, which
. . . posits that it is a better "bet" to believe that God exists than not to believe, because the expected value of believing (which Pascal assessed as infinite) is always greater than the expected value of not believing. (Wikipedia)
Those who "bet" on God, Pascal argues, lose nothing if they are wrong, but gain boundless life now and in the next world if they are right. Those who "bet" against God lose nothing if they are right, but gain nothing—and may reap eternal punishment in hell for the fact of their unbelief—if they are wrong.

As an argument for religious belief, Pascal's Wager is not persuasive. Philosophers and theologians have presented many criticisms of it since Pascal's time, but the chief difficulty with it is simple: No one commits to religious belief or unbelief because of a bet. People do not manage their spiritual lives that way.

As a rough guide to risk management, however, the Wager (which is actually an example of decision theory) can be useful. It can clarify issues, and in using it we are forced to make at least approximate predictions about the consequences of our wagers.

Consider its application to climate change. The scientific consensus is that the climate is growing warmer, and that human-generated greenhouse gases—mainly from burning fossil fuels—are a major cause of the change. Those who accept this theory argue for policies that will reduce our production of greenhouse gases. A small number of skeptics argue that any observed warming is part of a natural cycle and not subject to change by human action or inaction.

In the original Wager, readers were asked to "bet" by choosing whether to live as if God is real. Applying this reasoning to climate change, we "bet" by choosing either to live as if human actions—our actions—can make a difference or choosing to live as if our actions make little or no difference.

If our actions can make a difference, then we would want to make some changes in our way of life. For example:

  • We might invest in public transit to encourage people to drive less, thereby using less oil;
  • We might invest in technologies, existing and new ones, not based on fossil fuels, to generate electricity; and
  • We might invest in technologies that use less energy (e.g., compact fluorescent light bulbs) in order to use less fuel of any kind.
These actions and others we might take have one thing in common: All of them have side benefits quite apart from their effect on climate change. If we burn less fossil fuel, we will be less dependent on oil from unstable parts of the world, and our air will be less polluted. If we improve public transit and drive less, our roads will be less full and travel will become easier even for those who must drive (e.g., ambulances, which will get to hospitals faster). If we invest in sustainable technologies, we can open up new possibilities for economic development and jobs. Thus, even if we have bet wrongly and the skeptics turn out to be right, our world will be a cleaner and better place to live.

If, on the other hand, we bet that the skeptics are right, we need not take any actions to reduce our use of fossil fuels. We might want to for strategic reasons (to protect our economy from disruptions in oil supplies) or because we think reducing pollution is a good thing in itself. But nothing in the skeptics' position compels us to change. We would probably reduce pollution and fossil fuel usage less than if we had bet against the skeptics. Thus, if the skeptics turned out to be right, we would very likely be quite a lot worse off. The planet would still be warming alarmingly, the air would be more polluted, and we would still suffer from traffic jams and oil dependency.

If it turns out that the skeptics are wrong, and we have lived as if they were right, we would face the prospect of greater and faster global warming than if we had bet against the skeptics—and the air would likely be more polluted, the roads more jammed, and our lives far more at risk.

It should be an easy bet to make.

1 comment:

Anonymous said...

Good post.

But if we take climate change seriously, we are actually called upon to do more than opt for a less polluted, etc life.

• We must pay for it, and this means less money available for the rest of life. There are scads of projects that will save us money (think efficient light bulbs), but if we are to tackle greenhouse gas mitigation at the level experts in science and policy recommend, we must adapt solutions that are much more expensive. For example, utilities that have coal plants will face the option of adding carbon capture and storage, at more than 3 cent/kWh, or replacing the coal plant with another (there are limits on how many other types of plants exist and how rapidly we can build them). Here in CA we get a sizable amount of electricity from natural gas, already expensive, CCS will add 1.5? more? cent/kWh. Essentially no one in policy thinks that we will have enough solutions without technology change much faster than business as usual, so we must invest in R&D.

• We need to make choices that limit our options, for example, restrict flying.

• We must wrestle publicly about issues that many just wish would disappear. Many object to nuclear power, coal with CCS, cellulosic biofuels (next generation). Many object to how power line siting is determined, but we need more power lines, especially if wind is to be an important resource. We object to windmill siting. We object to solutions that include greater costs or that limit our individual choices. Etc

Your point that many of the solutions have side benefits is an important one. But this will not be true of all solutions. In some cases, like nuclear power, the primary disadvantage is that many will have to change their mind (but I'm always right!!!) For others, there may be costs in land use, water use, resentment from one group or other that doesn't see why it should pay more or have its options limited.

I hope to see more public discussion of the conflicts.