Updatelessness explained

Introduction This post introduces updatelessness to readers who are familiar with evidential and causal decision theory (EDT and CDT). Roughly, an updateless agent follows the policy that she would have wanted to commit to before learning which situation she is in, even if a different action seems best after she updates on her observations. I start with examples in which an agent would like to commit in advance to a policy that she will later want to deviate from. I use these examples to introduce pseudo-updateless agents like son-of-EDT and son-of-CDT, which follow policies they previously committed to. Then I describe full updatelessness, which requires no prior commitment and so applies even to situations that the agent is born into. After that, I give an argument for updatelessness based on an example in which combining EDT with updating leads to a clearly wrong choice. Finally, I describe different ways of thinking about updatelessness philosophically, distinguish between action and policy updatelessness, and briefly comment on logical updatelessness. Motivating examples Consider the following two scenarios: Parfit's Hitchhiker (quoted from Parfit’s Reasons and Persons) Parfit