Saturday, October 21, 2017

Pascal's Wager

I enjoyed this recent conversation between Julia Galef and Amanda Askell on the nuances of Pascal's wager. According to wikipedia:
Pascal argues that a rational person should live as though God exists and seek to believe in God. If God does actually exist, such a person will have only a finite loss (some pleasures, luxury, etc.), whereas they stand to receive infinite gains (as represented by eternity in Heaven) and avoid infinite losses (eternity in Hell).
I always thought this was something of a tongue-in-cheek argument because "of course" the argument fails the smell test. However, if we take it seriously, we find that it resists simple attempts at tearing it down. This blog post ("Common objections to Pascal's wager") outlines some of the rebuttals. It makes for interesting reading.

One of the things from the podcast that stuck with me was a comment about whether belief in climate change maps neatly onto Pascal's wager. Simplistically, let C be the claim that climate change is true, and ~C be the opposite claim. Let A denote action (taken to avert C), and ~A denote inaction (business as usual).

Then, we have the following four possibilities, A|C (action given climate change), A|~C, ~A|C, and ~A|~C.

A|C = mildly painful

An analogy might be something like an appendectomy. There is a problem (inflamed appendix or climate change), and appropriate corrective action is applied (surgical removal, CO2 reduction).

A|~C = mildly painful

An analogy would be unused insurance. You buy home insurance for a year, and nothing happens. You had to fork over premiums (which is mildly painful), but you accept that as reasonable risk against catastrophe.

~A|C = catastrophe

Piggybacking on the previous analogy, here your house is in flames and you realize you skimped on fire insurance. The external "shock" is bad (climate change or house catching fire), but your "penny-wise but pound-foolish" behavior made a bad situation much much worse.

~A|~C = mildly pleasurable

An analogy (which strikes close to home) might be skipping the annual dental checkup, and finding out nothing is wrong with your teeth. As someone once remarked to me, sometimes "pleasure is simply the absence of pain."

Note that the catastrophic outcome 3 (~A|C), with its "infinities", crowds out the others.

Hence, Pascal might argue that we should believe in both, God and climate change.

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