Many people argue that the effects of our actions are so diverse and unpredictable, that it’s impossible to know whether they’re ultimately good or bad.

The pop version of the criticism is when people point out that if you save a life, that person might become the next Hitler, so your well-intentioned action might have actually resulted in the deaths of millions.

This version of the criticism is silly, but it’s pointing at something real.

Every action we take causes ripple effects that extend indefinitely into the future, which have some probability of having enormously good or bad consequences over thousands of years, and we don’t know what they’ll be.

One implication is that ultimately there are no ‘evidence-based’ ways to do good. At best, we can measure the short-term effects of a course of action, but there are only a tiny minority of all of the consequences.

The interesting question is what this means in practice.

A strong response is the cancelling out argument. If we know that an action has some positive effects, but also many unknown effects, then if the unknown effects are just as likely to be good as to be bad, so [in expectation] they’re zero. In practice, we can (probably) ignore them.

However, not everyone thinks this response works. They have proposed a more advanced version of the puzzle, which has been called the ‘complex’ problem of cluelessness. This response tries to cast into doubt the idea that we can be confident the effects indeed cancel out.

If this argument is correct, it might lead us to a radically skeptical position – we can’t know whether the effects of any actions are ultimately good or bad from an impartial perspective.

We don’t accept this conclusion. We think the right response is to be extremely humble about what we can ever know, but then do our best to work out which kinds of actions have the best (non-cancelling out) long term effects, and to focus on those.

If you’d like to learn more, we’d recommend this great talk by Hilary Greaves:
Evidence, Cluelessness and the Long Term.

Further reading

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