
Kenneth Arrow Has Died - msabalau
https://www.nytimes.com/2017/02/21/business/economy/kenneth-arrow-dead-nobel-laureate-in-economics.html?_r=1
======
dnautics
This is possibly one of the slickest arrows theorem videos, made by the
exploratorium last year.

[https://youtu.be/tJag3vuG834](https://youtu.be/tJag3vuG834)

~~~
StreakyCobra
Related: For hackers, a well know example of community using a method other
than the simple majority rule is Debian. They use the Condorcet method [1] for
the election of their project leader [2]. It's a ranking method «that elects
the candidate that would win by majority rule, in all pairings, against the
other candidates».

[1]
[https://en.wikipedia.org/wiki/Condorcet_method](https://en.wikipedia.org/wiki/Condorcet_method)
[2] [https://www.debian.org/vote/](https://www.debian.org/vote/)

~~~
twic
It's a bit more precise to say that they use _a_ Condorcet method. There are
lots of different vote-counting systems that are Condorcet methods; the one
they use is particularly refined:

[https://en.wikipedia.org/wiki/Schulze_method](https://en.wikipedia.org/wiki/Schulze_method)

~~~
StreakyCobra
Didn't knew that, thanks!

------
oli5679
Two of his interesting contribution were his Arrow-Pratt measure of risk
aversion, which is invariant to affine transformations (so consistent with
revealed preference) and his Arrow-Debreu general equilibrium proof. Both are
quite intuitive:

[https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http:...](https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://public.econ.duke.edu/~rek8/econ604/lecturenotes/topic2notesparttwo.pdf&ved=0ahUKEwjuxNylqaPSAhXID8AKHToQCFIQFgg1MAI&usg=AFQjCNEzeiLw4Jt9C5gYimbpGR_s-M5RZg&sig2=vSej8BiN2OjTXt4SbpSPQA)
[https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http:...](https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://wwwf.imperial.ac.uk/~mdavis/docs/ArrowDebreuPrices.pdf&ved=0ahUKEwiNx57xqaPSAhXMDcAKHcX6BmUQFghYMAY&usg=AFQjCNGAnRtVKRk2wtJyd6kxkvi6lJknvQ&sig2=ZvF5qLcUgnJn9s1KzygWjg)

------
ClayShentrup
Here's a picture of me hanging out with him at his home in Palo Alto a couple
years ago.

[https://www.flickr.com/photos/brokenladder/9002915694/in/alb...](https://www.flickr.com/photos/brokenladder/9002915694/in/album-72157634035627773/)

He was a really nice guy. He signed some of his books for me.

------
kriro
He did so many things. I personally think the most interesting/stimulating
contribution was his paper "The Economic Implications of Learning by Doing"
from 1962.

~~~
dpfu
You have made me curios, so I'm going to read the paper. It lives under this
DOI
[10.2307/2295952]([https://doi.org/10.2307/2295952](https://doi.org/10.2307/2295952))
(paywalled).

~~~
curioustom
I am having a hard time understanding the paper. Would one of you be able to
summarize the implications of the paper?

I found this part interesting: "I advance the hypothesis here that technical
change in general can be ascribed to experience, that it is the very activity
of production which gives rise to problems for which favorable responses are
selected over time."

~~~
taylorwc
There is actually a little blurb in the linked NYT article on this topic:

 _Take “learning by doing,” a notion that Professor Arrow examined in the
early 1960s. The basic idea is straightforward: The more that a company
produces, the smarter it gets. Decades later, economists incorporated this
idea into sophisticated theories of “endogenous growth,” which have a
country’s rate of economic growth depending on internal policies that promote
innovation and education — the very forces that Professor Arrow’s writings
anticipated. "_

edit: I always forget which markdown pieces HN uses/doesn't use. Italicized
rather than failed attempt at blockquote

------
dj-wonk
Studying Arrow's work encouraged me to think about the complexities of
aggregating preferences. I look forward to reading more of his other work.
With economics there is more than meets the eye.

~~~
sevensor
Reading Arrow is one of the things that warmed me up to the European School
(Roy et al). Try to avoid policies that create big losers, instead of trying
to optimize a national utility function. It's also really interesting that in
the 1970s the Soviets were trying to do the latter -- it's one of the things
they wanted to do with their crazy mirror-universe arpanet.

------
dang
The story at the end is really good.

~~~
tzs
OT: speaking of whales, that reminds me of something I've wondered about.

I recall reading an article a few years ago about some species of whale that
lives in the Atlantic and spends the winter in warmer southern waters, and
then migrates north to their breeding grounds.

The article talked about how researchers had put trackers on some of the
whales, and found that the whales followed much straighter paths than the
researches expected. The expectation had been that there would be a lot of
east/west variation along the paths of individual whales, because all of the
geographic inputs to navigation the whales are thought to use (magnetic sense,
position of sun, maybe polarization of light from the sky, visible landmarks,
and so on) have a fair amount of uncertainty.

I did a bit of Googling, and found that there were tens of thousands of these
whales. The article didn't say how many whales had trackers attached, but I
would assume that it is only a very tiny fraction of the total population. I
also found that the migration is spread out, not all at once. Some whales will
leave, then a little later more will go, and so on, so that at the height of
the migration whales are all along the general route.

So what I've wondering is if the overly straight routes of the tracked whales
could be explained by most of the whales listening for the calls of the whales
further along in the migration and swimming in the direction of the calls, and
giving that priority over following geographic navigation clues. Since they
only track a small fraction of the whales, I could see them easily only having
data only from whales that are not near the leading edge of the migration.

The reason I think following would lead to straighter routes is that if B is
following A, with a gap of several kilometers (which should be easily doable,
because whale sounds can be heard quite far away under water), then if A
deviates side to side by a certain amount, B will also deviate, but B's
deviation will be smaller. The farther back B is, the smaller B's deviation
will be.

Now if there is a C following B a few kilometers back, C's deviations will be
even smaller than B's.

With a spread out migration, these chains should be long, and those whales
back a few steps in the chain should be going quite straight. If you only have
data on the whales that are a few steps back or more, it would look like the
whales have some super accurate navigation system.

