Bayesian Investor Blog

Book review: Good and Real: Demystifying Paradoxes from Physics to Ethics by Gary Drescher.

This book tries to derive ought from is. The more important steps explain why we should choose the one-box answer to Newcomb’s problem, then argue that the same reasoning should provide better support for Hofstadter’s idea of superrationality than has previously been demonstrated, and that superrationality can be generalized to provide morality. He comes close to the right approach to these problems, and I agree with the conclusions he reaches, but I don’t find his reasoning convincing.

He uses a concept which he calls a subjunctive relation, which is intermediate between a causal relation and a correlation, to explain why a choice that seems to happen after its goal has been achieved can be rational. That is the part of his argument that I find unconvincing. The subjunctive relation behaves a lot like a causal relation, and I can’t figure out why it should be treated as more than a correlation unless it’s equivalent to a causal relation.

I say that the one-box choice in Newcomb’s problem causes money to be placed in the box, and that superrationality and morality should be followed for similar reasons involving counterintuitive types of causality. It looks like Drescher is reluctant to accept this type of causality because he doesn’t think clearly enough about the concept of choice. It often appears that he is using something like a folk-psychology notion of choice that appears incompatible with the assumptions of Newcomb’s problem. I expect that with a sufficiently sophisticated concept of choice, Newcomb’s problem and similar situations cease to seem paradoxical. That concept should reflect a counterintuitive difference between the time at which a choice is made and the time at which it is introspectively observed as being irrevocable. When describing Kavka’s toxin problem, he talks more clearly about the concept of choice, and almost finds a better answer than subjunctive relations, but backs off without adequate analysis.

The book also has a long section explaining why the Everett interpretation of quantum mechanics is better than the Copenhagen interpretation. The beginning and end of this section are good, but there’s a rather dense section in the middle that takes much effort to follow without adding much.