# Func­tional De­ci­sion Theory

TagLast edit: 17 Nov 2022 5:31 UTC by

Functional Decision Theory is a decision theory described by Eliezer Yudkowsky and Nate Soares which says that agents should treat one’s decision as the output of a ﬁxed mathematical function that answers the question, “Which output of this very function would yield the best outcome?”. It is a replacement of Timeless Decision Theory, and it outperforms other decision theories such as Causal Decision Theory (CDT) and Evidential Decision Theory (EDT). For example, it does better than CDT on Newcomb’s Problem, better than EDT on the smoking lesion problem, and better than both in Parﬁt’s hitchhiker problem.

In Newcomb’s Problem, an FDT agent reasons that Omega must have used some kind of model of her decision procedure in order to make an accurate prediction of her behavior. Omega’s model and the agent are therefore both calculating the same function (the agent’s decision procedure): they are subjunctively dependent on that function. Given perfect prediction by Omega, there are therefore only two outcomes in Newcomb’s Problem: either the agent one-boxes and Omega predicted it (because its model also one-boxed), or the agent two-boxes and Omega predicted that. Because one-boxing then results in a million and two-boxing only in a thousand dollars, the FDT agent one-boxes.

# Is it jus­tifi­able for non-ex­perts to have strong opinions about Gaza?

8 Jan 2024 17:31 UTC
23 points

# The om­ni­zoid—Heighn FDT De­bate #5

18 Sep 2023 11:54 UTC
4 points

# The om­ni­zoid—Heighn FDT De­bate #3: Con­tra om­ni­zoid con­tra me con­tra om­ni­zoid con­tra FDT

14 Sep 2023 11:52 UTC
6 points

# De­ci­sion The­ory: A (Nor­ma­tive) Introduction

6 Sep 2023 8:22 UTC
−1 points
(paretooptimal.substack.com)

# The om­ni­zoid—Heighn FDT De­bate #1: Why FDT Isn’t Crazy

4 Sep 2023 12:57 UTC
24 points

# New­comb Variant

29 Aug 2023 7:02 UTC
25 points

# Any­one want to de­bate pub­li­cly about FDT?

29 Aug 2023 3:45 UTC
13 points

# Ex­plor­ing Func­tional De­ci­sion The­ory (FDT) and a mod­ified ver­sion (ModFDT)

5 Jul 2023 14:06 UTC
8 points

# An ex­pla­na­tion of de­ci­sion theories

1 Jun 2023 3:42 UTC
20 points

# Threat­en­ing to do the im­pos­si­ble: A solu­tion to spu­ri­ous coun­ter­fac­tu­als for func­tional de­ci­sion the­ory via proof theory

11 Feb 2023 7:57 UTC
5 points

# Quan­tum Suicide, De­ci­sion The­ory, and The Multiverse

22 Jan 2023 8:44 UTC
4 points
(voidgoddess.org)

# You’re Not One “You”—How De­ci­sion The­o­ries Are Talk­ing Past Each Other

9 Jan 2023 1:21 UTC
27 points

# FDT is not di­rectly com­pa­rable to CDT and EDT

29 Sep 2022 14:42 UTC
36 points

# FDT defects in a re­al­is­tic Twin Pri­son­ers’ Dilemma

15 Sep 2022 8:55 UTC
37 points

# New­comb­ness of the Din­ing Philoso­phers Problem

6 Aug 2022 21:58 UTC
10 points

# [Question] Al­gorith­mic for­mal­iza­tion of FDT?

8 May 2022 1:36 UTC
12 points

# [Question] What does Func­tional De­ci­sion The­ory say to do in im­perfect New­comb situ­a­tions?

7 May 2022 22:26 UTC
4 points

# No, EDT Did Not Get It Right All Along: Why the Coin Flip Creation Prob­lem Is Irrelevant

30 Mar 2022 18:41 UTC
6 points

# Alex Tabar­rok ad­vo­cates for crowd­fund­ing sys­tems with *Re­fund Bonuses*. I think this might be a nat­u­ral oc­cur­rence of a money pump against Causal De­ci­sion The­ory pledgers

14 Mar 2022 7:27 UTC
17 points
(marginalrevolution.com)

# An In­tu­itive In­tro­duc­tion to Func­tional De­ci­sion Theory

7 Mar 2022 16:07 UTC
19 points

# Defend­ing Func­tional De­ci­sion Theory

8 Feb 2022 14:58 UTC
4 points

# Cri­tiquing Scasper’s Defi­ni­tion of Sub­junc­tive Dependence

10 Jan 2022 16:22 UTC
1 point

# A Re­ac­tion to Wolf­gang Sch­warz’s “On Func­tional De­ci­sion The­ory”

5 Jan 2022 9:00 UTC
7 points

# A Defense of Func­tional De­ci­sion Theory

12 Nov 2021 20:59 UTC
21 points

# MIRI/​OP ex­change about de­ci­sion theory

25 Aug 2021 22:44 UTC
54 points

# Violent Un­rav­el­ing: Suici­dal Majoritarianism

29 Jul 2021 9:29 UTC
6 points

# AXRP Epi­sode 5 - In­fra-Bayesi­anism with Vanessa Kosoy

10 Mar 2021 4:30 UTC
35 points

# Dis­solv­ing Con­fu­sion around Func­tional De­ci­sion Theory

5 Jan 2020 6:38 UTC
32 points

# A Cri­tique of Func­tional De­ci­sion Theory

13 Sep 2019 19:23 UTC
86 points

# De­con­fus­ing Log­i­cal Counterfactuals

30 Jan 2019 15:13 UTC
27 points

# Let’s Dis­cuss Func­tional De­ci­sion Theory

23 Jul 2018 7:24 UTC
29 points