Can someone briefly explain to me the difference between functional and updateless decision theory / where FDT performs better? That would be much appreciated. I have not yet read FDT because it does not mention UDT (I checked) and I want to understand why UDT needs “fixing” before I invest the time.
“UDT” is ambiguous and has been used to refer to a number of different approaches; “FDT” is a new name for the central cluster of UDT-ish theories (excluding some similar theories like TDT), intended to be less ambiguous and easier to explain (especially to working decision theorists).
In part it’s easier to explain because it’s formulated in a more CDT-like fashion (whereas Wei Dai’s formulations are more EDT-like), and in part it’s easier to explain because it builds in less content: accepting FDT doesn’t necessarily require a commitment to some of the philosophical ideas associated with updatelessness and logical prior probability that MIRI, Wei Dai, or other FDT proponents happen to accept. In particular, some of Nate’s claims in the linked post are stronger than is strictly required for FDT.
My impression (based in part on this humorous piece) is that FDT is primarily a better formulation than UDT & TDT, but doesn’t necessarily make better decisions.
Functional decision theory has been developed in many parts through (largely unpublished) dialogue between a number of collaborators. FDT is a generalization of Dai’s (2009) “updateless decision theory” and a successor to the “timeless decision theory” of Yudkowsky (2010).
Can someone briefly explain to me the difference between functional and updateless decision theory / where FDT performs better? That would be much appreciated. I have not yet read FDT because it does not mention UDT (I checked) and I want to understand why UDT needs “fixing” before I invest the time.
“UDT” is ambiguous and has been used to refer to a number of different approaches; “FDT” is a new name for the central cluster of UDT-ish theories (excluding some similar theories like TDT), intended to be less ambiguous and easier to explain (especially to working decision theorists).
In part it’s easier to explain because it’s formulated in a more CDT-like fashion (whereas Wei Dai’s formulations are more EDT-like), and in part it’s easier to explain because it builds in less content: accepting FDT doesn’t necessarily require a commitment to some of the philosophical ideas associated with updatelessness and logical prior probability that MIRI, Wei Dai, or other FDT proponents happen to accept. In particular, some of Nate’s claims in the linked post are stronger than is strictly required for FDT.
Thanks! So UDT is integrated. That’s good to hear.
My impression (based in part on this humorous piece) is that FDT is primarily a better formulation than UDT & TDT, but doesn’t necessarily make better decisions.
Ah. And the paper says (emphasis mine)