Moral uncertainty

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Moral uncertainty (or normative uncertainty) is uncertainty about how to act given the diversity of moral doctrines. It includes a level of uncertainty above the more usual uncertainty of what to do given incomplete information, since it deals also with uncertainty about which moral theory is right. Even with complete information about the world this kind of uncertainty would still remain [1] In lower levels of uncertainty, one can have doubts on how to act because all the relevant empirical information isn’t available, for example choosing whether to implement or not a new technology (e.g.: AGI, Biological Cognitive Enhancement,Mind Uploading) not fully knowing about its consequences and nature. But even if we ideally get to know each and every consequences of a new technology, we would still need to know which is the right ethical perspective for analyzing these consequences. For example, if we known for certain that a new technology would enable more humans to live in another planet with slight less welfare than on Earth Wikipedia:Terraforming. An average utilitarian would consider these consequences as bad, while a total utilitarian would endorse such technology. If we are uncertain about which of these two theories are right, what should we do? One approach is to follow only the most probable theory. This has its own problems. For example, what if the most probable theory points only weakly in one way, and other theories point strongly the other way? A better approach is to “perform the action with the highest expected moral value. We get the expected moral value of an action by multiplying the subjective probability that some theory is true by the value of that action if it is true, doing the same for all of the other theories, and adding up the results.” [2] However, we would still need method of comparing value intertheories, a utilon in one theory may not be the same with a utilon in another theory. Outside consequentialism there many ethical theories that doesn’t use utilions or any quantifiable values. This is still a open problem.

Nick Bostrom and Toby Ord have proposed a parliamentary model. In this model, each theory sends a number of delegates to a parliament in proportion to its probability. The theories then bargain for support as if the probability of each action were proportional to its votes. However, the actual output is always the action with the most votes. Bostrom and Ord's proposal lets probable theories determine most actions, but still gives less probable theories influence on issues they consider unusually important.

Blog posts

External links


  1. Crouch, William. (2010) “Moral Uncertainty and Intertheoretic Comparisons of Value” BPhil Thesis, 2010. p. 6. Available at:
  2. Sepielli, Andrew. (2008) “Moral Uncertainty and the Principle of Equity among Moral Theories". ISUS-X, Tenth Conference of the International Society for Utilitarian Studies, Kadish Center for Morality, Law and Public Affairs, UC Berkeley. Available at:

See also