# Oc­cam’s Razor

TagLast edit: 4 Jan 2022 15:35 UTC by

Occam’s razor (more formally referred to as the principle of parsimony) is a principle commonly stated as “Entities must not be multiplied beyond necessity”. When several theories are able to explain the same observations, Occam’s razor suggests the simpler one is preferable. It must be noted that Occam’s razor is a requirement for the simplicity of theories, not for the size of the systems described by those theories. For example, the immensity of the Universe isn’t at odds with the principle of Occam’s razor.

Occam’s razor is necessitated by the conjunction rule of probability theory: the conjunction A and B is necessarily less (or equally, in the case of logical equivalence) probable than the A alone; every detail you tack onto your story drives the probability down.

Occam’s razor has been formalized as Minimum Description Length or Minimum Message Length, in which the total size of the theory is the length of the message required to describe the theory, plus the length of the message required to describe the evidence using the theory. Solomonoff induction is the ultimate case of minimum message length in which the code for messages can describe all computable hypotheses. This has jokingly been referred to as “Solomonoff’s lightsaber”.

# Solomonoff in­duc­tion still works if the uni­verse is un­com­putable, and its use­ful­ness doesn’t re­quire know­ing Oc­cam’s razor

18 Jun 2023 1:52 UTC
38 points

# Mes­sage Length

20 Oct 2020 5:52 UTC
134 points

# Belief in the Im­plied Invisible

8 Apr 2008 7:40 UTC
59 points

# Msg Len

12 Oct 2020 3:35 UTC
65 points

# Very Short In­tro­duc­tion to Bayesian Model Com­par­i­son

16 Jul 2019 19:48 UTC
32 points

# [Question] What is an “anti-Oc­camian prior”?

23 Oct 2023 2:26 UTC
35 points

# [Question] In­stru­men­tal Oc­cam?

31 Jan 2020 19:27 UTC
30 points

# Tak­ing Oc­cam Seriously

29 May 2009 17:31 UTC
32 points

# A Semitech­ni­cal In­tro­duc­tory Dialogue on Solomonoff Induction

4 Mar 2021 17:27 UTC
139 points

# Oc­cam’s Ra­zor and the Univer­sal Prior

3 Oct 2021 3:23 UTC
28 points

# Math­e­mat­ics as a lossy com­pres­sion al­gorithm gone wild

6 Jun 2014 23:53 UTC
53 points

# Bias to­wards sim­ple func­tions; ap­pli­ca­tion to al­ign­ment?

18 Aug 2022 16:15 UTC
3 points

# In­duc­tion; or, the rules and eti­quette of refer­ence class tennis

3 Mar 2013 23:27 UTC
11 points

# Oc­cam’s Razor

26 Sep 2007 6:36 UTC
118 points

# Notes on Simplicity

2 Dec 2020 23:14 UTC
9 points

# Dis­solv­ing the Prob­lem of Induction

27 Dec 2020 17:58 UTC
40 points

# A Proof of Oc­cam’s Razor

10 Aug 2010 14:20 UTC
0 points

# Prob­a­bil­ity the­ory im­plies Oc­cam’s razor

18 Dec 2020 7:48 UTC
8 points

# State, Art, Identity

25 Jan 2021 20:22 UTC
1 point

# [Question] What qual­ities does an AGI need to have to re­al­ize the risk of false vac­uum, with­out hard­cod­ing physics the­o­ries into it?

3 Feb 2023 16:00 UTC
1 point

# What kind of place is this?

25 Feb 2023 2:14 UTC
24 points

# Ex­pla­na­tions as Hard to Vary Assertions

24 Sep 2021 11:33 UTC
17 points

# Not us­ing a pri­ori in­for­ma­tion for Rus­sian propaganda

24 Apr 2023 1:14 UTC
−3 points

# Blunt Razor

24 Oct 2023 17:27 UTC
3 points

# The Strong Oc­cam’s Razor

11 Nov 2010 17:28 UTC
17 points

# Oc­cam’s Ra­zor May Be Suffi­cient to In­fer the Prefer­ences of Ir­ra­tional Agents: A re­ply to Arm­strong & Mindermann

7 Oct 2019 19:52 UTC
47 points

# Against Oc­cam’s Razor

5 Apr 2018 17:59 UTC
4 points

# If Many-Wor­lds Had Come First

10 May 2008 7:43 UTC
84 points

# Where Re­cur­sive Jus­tifi­ca­tion Hits Bottom

8 Jul 2008 10:16 UTC
119 points

# A Priori

8 Oct 2007 21:02 UTC
83 points

# De­co­her­ence is Simple

6 May 2008 7:44 UTC
67 points

# Kevin T. Kelly’s Ock­ham Effi­ciency Theorem

16 Aug 2010 4:46 UTC
43 points

# The prior of a hy­poth­e­sis does not de­pend on its complexity

26 Aug 2010 13:20 UTC
34 points

# How do low level hy­pothe­ses con­strain high level ones? The mys­tery of the dis­ap­pear­ing di­a­mond.

11 Jul 2023 19:27 UTC
17 points