Posted on 2018-12-09.

My main interest in this book was the question of voting - I wanted to see his response to the argument that since your vote is extremely unlikely to change the outcome of the election, and voting carries some cost (in time, money, whatever), it’s not rational to vote. As I understood it, the response is that:

1. Your vote does have a high chance of being part of the set of votes that cause the outcome (e.g., if the candidate needs 51% of the vote to win, and actually receives 60%, then if you think of the ballots as being counted in some order, there’s a good chance that your ballot is part of the 51% that were necessary rather than the 9% that were superfluous).
2. Each vote in that set should be thought of as fully causing the outcome.
3. It can be rational to want to cause an outcome even though the outcome would still have occurred even if you had not.

I don’t find this fully satisfying, but it is interesting food for thought. The book also contains an illuminating discussion of the similarities, differences, and relationships between various types of problems related to collective action, and a fascinating recounting of the history of such problems.