(note: this is a copy of my LW post. I'm gathering all my stuff in one place)
There are two insights from Bayesianism which occurred to me and which I hadn't seen anywhere else before.
I like lists in the two posts linked above, so for the sake of completeness, I'm going to add my two cents to a public domain. This post is about the second penny, the first one is here.
(followup to What Bayesianism has taught me? and Bayesianism for Humans, relevant to Boring Advice Repository )
There are two insights from Bayesianism which occurred to me and which I hadn't seen anywhere else before.
I like lists in the two posts linked above, so for the sake of completeness, I'm going to add my two cents to a public domain. This post is about the second penny, the first one is here.
Prosaic Priors
The second insight can be formulated as «the dull explanations are more likely to be correct because they tend to have high prior probability.»
Why is that?
1) Almost by definition! Some property X is 'banal' if X applies to a lot of people in an disappointingly mundane way, not having any redeeming features which would make it more rare (and, hence, interesting).
In the other words, X is banal iff base rate of X is high. Or, you can say, prior probability of X is high.
1.5) Because of Occam's Razor and burdensome details.
One way to make something boring more exciting is to add interesting
details: some special features which will make sure that this
explanation is about you as opposed to 'about almost anybody'.
This
could work the other way around: sometimes the explanation feels
unsatisfying exactly because it was shaved of any unnecessary and
(ultimately) burdensome details.
2)
Often, the alternative of a mundane explanation is something unique and
custom made to fit the case you are interested in. And anybody familiar
with overfitting and conjunction fallacy (and the fact that people tend to love coherent stories with blinding passion1)
should be very suspicious about such things. So, there could be a
strong bias against stale explanations, which should be countered.
* * *
I
fully grokked this when being in process of CBT-induced soul-searching;
usage in this context still looks the most natural to me, but I believe
that the area of application of this heuristic is wider.
Examples
1)
I'm fairly confident that I'm an introvert. Still, sometimes I can
behave like an extrovert. I was interested in the causes of this
"extroversion activation", as I called it2. I suspected that I
really had two modes of functioning (with "introversion" being the
default one), and some events — for example, mutual interest (when I am
interested in a person I was talking to, and xe is interested in me) or
feeling high-status — made me switch between them.
Or,
you know, it could be just reduction in a social anxiety, which makes
people more communicative. Increased anxiety levels wasn't a new element
to be postulated; I already knew I had it, yet I was tempted to make up
new mental entities, and prosaic explanation about anxiety managed to
avoid me for a while.
2)
I find it hard to do something I consider worthwhile while on a spring
break, despite having lots of a free time. I tend to make grandiose
plans — I should meet new people! I should be more involved in sports! I
should start using Anki! I should learn Lojban! I should practice
meditation! I should read these textbooks including doing most of
exercises! — and then fail to do almost anything. Yet I manage to do
some impressive stuff during academic term, despite having less time and
more commitments.
This paradoxical situation calls for explanation.
The
first hypothesis that came to my mind was about activation energy. It
takes effort to go from "procrastinating" to "doing something";
speaking more generally, you can say that it takes effort to go from
"lazy day" to "productive day". During the academic term, I am forced to
make most of my days productive: I have to attend classes, do homework,
etc. And, already having done something good, I can do something else
as well. During spring break, I am deprived of that natural structure,
and, hence I am on my own in terms of starting doing something I find
worthwhile.
The
alternative explanation: I was tired. Because, you know, vacation comes
right after midterms, and I tend to go all out while preparing for
midterms. I am exhausted, my energy and willpower are scarce, so it's no
wonder I am having trouble utilizing it.
(I
don't really believe in the latter explanation (I think that my
situation is caused by several factors, including two outlined above),
so it is also an example of descriptive "probable enough" hypothesis)
3) This example comes from Slate Star Codex.
Nerds tend to find aversive many group bonding activities usual people
supposedly enjoy, such as patriotism, prayer, team sports, and pep
rallies. Supposedly, they should feel (with a tear-jerking passion of
thousand exploding suns) the great unity with their fellow citizens,
church-goers, teammates or pupils respectively, but instead they feel
nothing.
Might
it be that nerds are unable to enjoy these activities because something
is broken inside their brains? One could be tempted to construct an
elaborate argument involving autism spectrum and a mild case of schizoid
personality disorder. In other words, this calls for postulating a rare
form of autism which affects only some types of social behaviour
(perception of group activities), leaving other types unchanged.
Or,
you know, maybe nerds just don't like the group they are supposed to
root for. Maybe nerds don't feel unity and relationship to The Great
Whole because they don't feel like they truly belong here.
As
Scott put it, "It’s not that we lack the ability to lose ourselves in
an in-group, it’s that all the groups people expected us to lose
ourselves in weren’t ones we could imagine as our in-group by any
stretch of the imagination"3.
4) This example comes from this short comic titled "Sherlock Holmes in real life".
5) Scott Aaronson uses something similar to the Hanlon's Razor to explain that the lack of practical expertise of CS theorists aren't caused by arrogance or something like that:
"If theorists don’t have
as much experience building robots as they should have, don’t know as
much about large software projects as they should know, etc., then
those are all defects to add to the long list of their other, unrelated
defects. But it would be a mistake to assume that they failed to
acquire this knowledge because of disdain for practical people, rather than for mundane reasons like busyness or laziness."
6) (NEW) An answer seen in an Quora thread titled "Why aren't there a lot of old programmers at software companies?". I feel like an answer by Zach Brook is worth quoting (almost) in its entirety:
Demographics. There weren't very many programmers 40 years ago, so therefore there aren't many programmers with 40 years of experience. Ditto 30 and 20.
Note that this explanation is straightforward and does not require:
- Mass stereotyping of older developers
- Conspiracy theories involving hiring managers at thousands of companies colluding
- Characterization of modern companies as no longer solving interesting or hard technical problems
- Blaming 20-something-year-olds (a.k.a "kids these days")
- Suspension of disbelief in the free market
* * *
...and
after this the word "prosaic" quickly turned into an awesome
compliment. Like, "so, this hypothesis explains my behaviour well; but is it boring enough?", or "your claim is refreshingly dull; I like it!".
1. If you had read Thinking: Fast and Slow, you probably know what I mean. If you hadn't, you can look at narrative fallacy in order to get a general idea.
2. Which was, as I now realize, an excellent way to deceive myself via using word with a lot of hidden assumptions. Taboo your words, folks!
3. As a side note, my friend proposed an alternative explanation: the thing is, often nerds are defined
as "sort of people who dislike pep rallies". So, naturally, we have
"usual people" who like pep rallies and "nerds" who avoid them. And then
"nerds dislike pep rallies" is tautology rather than something to be
explained.
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