“You must wager. It is not optional. You are embarked. Which will you choose then?… You have two things to loose, the true and the good; and two things to stake, your reason & will and your knowledge & happiness; and your nature has two things to shun, error and misery. Your reason is no more shocked in choosing one rather than the other, since you must of necessity choose. This is one point settled. But your happiness? Let us weigh again the loss in wagering that God is. Let us estimate these two chances. If you gain, you gain all; if you lose, you lose nothing. Wager, then, without hesitation, that He is.”
While this proposition of Pascal’s is clothed in obscure religious language and on a religious topic, it is a significant and early expression of decision theory. Stripped of all its particulars, it provides a simple and effective way to reason about contemporary problems like climate change.
We don’t need to be 100% sure that the worst fears of climate scientists are correct in order to act. All we need to think about are the consequence of being wrong.
Let’s assume for a moment that there is no human-caused climate change and the consequences are not dire and we’ve made bug investments to avert it. What’s the worst that happens? In order to deal with climate change:
1. We’ve made major investments in renewable energy.
2. We’ve invested in a potent new source of jobs.
3. We’ve reduced dependence on oil from hostile or unstable regions.
4. We’ve migrated enormous off-the-books economic losses from pollution.
5. We’ve renewed our industrial base, investing in new industries rather than propping up old ones.
By contrast, let’s assume climate skeptics are wrong. We face displacement of millions of people, droughts, floods, species loss, economic harm that makes us long for the good-old-days of the current financial industry meltdown.
On the one side, the worst outcome is that we’ve built a more robust economy. On the other side, the worst outcome really is Hell.
Pascal’s wager is not just for mathematicians, or for the religiously inclined. It is a useful tool for any thinking person.
- Tim O'Reilly
[Essay in This explains Everything: 150 Deep, Beautiful, and Elegant Theories of How the World Works (Edge Question Series)]