The Nonlinear Library EA - Summary: The scope of longtermism by Global Priorities Institute
Dec 18, 2023
07:45
Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Summary: The scope of longtermism, published by Global Priorities Institute on December 18, 2023 on The Effective Altruism Forum.
This is a summary of the GPI Working Paper "The scope of longtermism" by David Thorstad. The summary was written by Riley Harris.
Recent work argues for longtermism - the position that often our morally best options will be those with the best long-term consequences.[1] Proponents of longtermism sometimes suggest that in most decisions expected long-term benefits outweigh all short-term effects. In 'The scope of longtermism', David Thorstad argues that most of our decisions do not have this character. He identifies three features of our decisions that suggest long-term effects are only relevant in special cases: rapid diminution - our actions may not have persistent effects, washing out - we might not be able to predict persistent effects, and option unawareness - we may struggle to recognise those options that are best in the long term even when we have them.
Rapid diminution
We cannot know the details of the future. Picture the effects of your actions rippling out in time - at closer times, the possibilities are clearer. As our prediction journeys further, the details become obscured. Although the probability of desired effects becomes ever lower, the effects might grow larger. In the long run, we could perhaps improve many billions or trillions of lives.
When we weight value by probability, the value of our actions will depend on a race between diminishing probabilities and growing possible impact. If the value increases faster than probabilities fall, the expected values of the action might be vast. Alternatively, if the chance we have such large effects falls dramatically compared to the increase in value, the expected value of improving the future might be quite modest.
Thorstad suggests that the latter of these effects dominates, so we should believe we have little chance of making an enormous difference. Consider a huge event that would be likely to change the lives of people in your city - perhaps, your city being blown up. Surprisingly, even this might not have large long-run impacts. Studies indicate that just half a century after cities in Japan and Vietnam were bombed, there was no longer any detectable effect on population size, poverty rates and consumption patterns.[2] To be fair, some studies indicate that some events have long-term effects,[3] but Thorstad thinks '...the persistence literature may not provide strong support' to longtermism.
Washing out
Thorstad's second concern with longtermism relates to our ability to predict the future. If our actions can affect the future in a huge way, these effects could be wonderful or terrible. They will also be very difficult to predict. The possibility that our acts will be enormously
beneficial does not make our acts particularly appealing when they might be equally terrible. If our ability to forecast long-term outcomes is limited, the potential positive and negative values would wash out in expectation.
Thorstad identifies three reasons to doubt our ability to forecast the long term. First, we have no track record of making predictions at the timescale of centuries or millennia. Our ability to predict only 20-30 years into the future is not great - and things get more difficult when we try to glimpse the further future.
Second, economists, risk analysts and forecasting practitioners doubt our ability to make long-term predictions, and often refuse to make them.[5] Third, we want to forecast how valuable our actions are over the long run. But value is a particularly difficult target - it includes many variables such as the number of people alive, their health, longevity, education and social inclusion.
That said, we sometimes have some evidence, and this evidence might point t...
This is a summary of the GPI Working Paper "The scope of longtermism" by David Thorstad. The summary was written by Riley Harris.
Recent work argues for longtermism - the position that often our morally best options will be those with the best long-term consequences.[1] Proponents of longtermism sometimes suggest that in most decisions expected long-term benefits outweigh all short-term effects. In 'The scope of longtermism', David Thorstad argues that most of our decisions do not have this character. He identifies three features of our decisions that suggest long-term effects are only relevant in special cases: rapid diminution - our actions may not have persistent effects, washing out - we might not be able to predict persistent effects, and option unawareness - we may struggle to recognise those options that are best in the long term even when we have them.
Rapid diminution
We cannot know the details of the future. Picture the effects of your actions rippling out in time - at closer times, the possibilities are clearer. As our prediction journeys further, the details become obscured. Although the probability of desired effects becomes ever lower, the effects might grow larger. In the long run, we could perhaps improve many billions or trillions of lives.
When we weight value by probability, the value of our actions will depend on a race between diminishing probabilities and growing possible impact. If the value increases faster than probabilities fall, the expected values of the action might be vast. Alternatively, if the chance we have such large effects falls dramatically compared to the increase in value, the expected value of improving the future might be quite modest.
Thorstad suggests that the latter of these effects dominates, so we should believe we have little chance of making an enormous difference. Consider a huge event that would be likely to change the lives of people in your city - perhaps, your city being blown up. Surprisingly, even this might not have large long-run impacts. Studies indicate that just half a century after cities in Japan and Vietnam were bombed, there was no longer any detectable effect on population size, poverty rates and consumption patterns.[2] To be fair, some studies indicate that some events have long-term effects,[3] but Thorstad thinks '...the persistence literature may not provide strong support' to longtermism.
Washing out
Thorstad's second concern with longtermism relates to our ability to predict the future. If our actions can affect the future in a huge way, these effects could be wonderful or terrible. They will also be very difficult to predict. The possibility that our acts will be enormously
beneficial does not make our acts particularly appealing when they might be equally terrible. If our ability to forecast long-term outcomes is limited, the potential positive and negative values would wash out in expectation.
Thorstad identifies three reasons to doubt our ability to forecast the long term. First, we have no track record of making predictions at the timescale of centuries or millennia. Our ability to predict only 20-30 years into the future is not great - and things get more difficult when we try to glimpse the further future.
Second, economists, risk analysts and forecasting practitioners doubt our ability to make long-term predictions, and often refuse to make them.[5] Third, we want to forecast how valuable our actions are over the long run. But value is a particularly difficult target - it includes many variables such as the number of people alive, their health, longevity, education and social inclusion.
That said, we sometimes have some evidence, and this evidence might point t...