
Malthusianisms - gojomo
http://www.scottaaronson.com/blog/?p=418
======
scythe
Malthus introduced exponential growth rates, but not equilibria; he assumed a
runaway growth would lead to collapse. Logistic functions, which describe
equilibrium-finding, were introduced by Pierre Verhulst.

<http://en.wikipedia.org/wiki/Pierre_Fran%C3%A7ois_Verhulst>

John von Neumann and John Nash deserve some credit for founding game theory;
in particular the strategies described are minimax strategies, introduced by
von Neumann.

<http://en.wikipedia.org/wiki/Minimax>

~~~
SiVal
I agree that these aren't Malthusian, and some aren't even true. The ones that
are true seem to exemplify incentives and constraints. When you have an
incentive to do more, you do more until either the incentive (marginal_benefit
- marginal_cost) or your ability to do a little more fades to zero. When the
incentives or constraints change, the behavior adapts accordingly. A
Malthusian collapse is a special case that is not relevant to most situations
of incentives and constraints.

~~~
CWuestefeld
But the reason that Malthus' doom-mongering hasn't come to pass is because he
failed to consider that there was sufficient incentive for people to find
alternatives, such that they could skirt the constraints.

Malthus said that the carrying capacity of Earth is limited to X because of
finite arable land (and so on). But then humans came up with irrigation, and
crop rotation, and terracing, and selective breeding, and fertilizers and
insecticides, and powered machinery, etc., all of which allowed the Earth to
provide for ever-increasing numbers of people.

Malthus saw humanity as limited to subsistence dirt farming, but the people
saw the ability to prosper, have large families, etc., as sufficient incentive
to invent alternatives. The incentives didn't change, and the constraints only
changed so far as did the body of human knowledge.

~~~
slowpoke
It is true, though, that there is a limit to how much people this planet can
reasonably sustain, and I'd say we're billions over that mark - the only
reason the system still works (barely) is because a large part of the world's
population lives in poverty and hunger.

Optimization will only get you so far. We simply can't optimize away the fact
that there _is_ limited space on this planet and that we're pretty much out of
it already. We can't sustain 7 billion people, tendency growing. Not at a
humane average living standard.

~~~
kbolino
I don't think you deserve the downvotes; your point may be valid, even if
pessimistic. Just because we've managed to overcome what seemed to be
infeasible hurdles doesn't mean we will continue to do so. Of course, just
because the new hurdles seem even less feasible doesn't mean we won't overcome
them, either. The point being that you'll never know you're at the cusp until
you're well into the valley on the other side.

Malthus was wrong about the long-run behavior of populations, but I think it's
worthwhile to note that we can feed yesterday's population today. World hunger
could have been a solved problem with all the advances that were made. But who
has the right to tell you not to breed?

~~~
CWuestefeld
Well, the argument needed to be made because there are so many who subscribe
to it.

But the important point that this misses is that the availability of any given
resource isn't what's critical, since all throughout history it's been shown
that human ingenuity has been able to find alternatives.

The critical factor is that human ingenuity. And because that human factor --
the availability of someone who can figure out that alternative, and who has
the incentive to do so -- is growing with the growth of the population, are
horizons are only broadening!

Contrary to Malthus, an increasing population is, in the long run, _better_
for mankind's prospects.

~~~
_delirium
I'm not at all sure the last part is true. It's difficult to do experiments in
history, of course, but there are historical examples of quite fast-advancing
societies with smallish, stable populations, and of not-making-progress
societies with large and growing populations. Enough that I doubt any general
causal relationship between population growth and technological advances or
quality of life.

------
mcherm
Why does the quality of a news site like slashdot, digg, reddit, or Hacker
News deteriorate until it reaches annoying levels? Because if it didn't, then
more and more people would join, reducing the average quality of the
participant pool.

~~~
tokenizer
which is a good thing considering by the time that happens to reddit, kn0thing
will have made his impact, and will be able to do whatever else he wants, and
somebody else's site will be the new and popular one (until it is).

~~~
astrodust
Reddit crossed that event horizon a year ago. People inside just haven't
realized yet.

~~~
bgilroy26
That's true.

The only thing that Reddit has going for it is that has a way to build new
communities built in. /r/DepthHub, /r/math, and /r/askscience are doing just
fine.

~~~
baq
/r/askscience is nearly 600 _thousand_ subscribers, that's hardly 'only'.
subreddits are as good as their moderators and that's also true of HN.

~~~
astrodust
Perhaps an astrophysicist will one day explain why communities like Reddit
tend to implode.

Once the "pressure" of those in the core, which are the ones doing most of the
work to keep people in line and promote healthy community behavior, start to
fizzle out and aren't replaced, the core will implode and the whole thing will
go supernova.

Smaller communities, like smaller stars, seem to have much longer lifespans.

The good news is when a site like Digg or Reddit goes supernova it spreads a
lot of well-intentioned people around the greater internet to create their own
new communities and start the process all over again.

------
jamesaguilar
Not all of these are actually even the case, to say nothing of the responses
being correct. For example, wedding clothing isn't that expensive, and the
people I've wanted to date have for the most part never been cruel or aloof.
Just because an explanation sounds obvious doesn't mean it is correct.

~~~
TheSOB88
Eh, I think some of these are circumstantial. The dating one probably applies
to a very specific type of person. This is the one that does it for me:

Why are even some affluent parts of the world running out of fresh water?
Because if they weren’t, they’d keep watering their lawns until they were.

It's all about greed/constraints/pressures/incentives/desires. People want to
use water, but people don't have an incentive to keep water use down. Instead,
they put pressure on engineers to bring availability up. And when
availability, or supply, goes up, demand comes back in to seal the gap.

~~~
jamesaguilar
Economics was aware of overconsumption of underpriced resources before Thomas
Malthus. It's not really a Malthusian observation to say that if a good is
priced lower than the cost of acquiring it, it will be over-consumed.

------
scarmig
Why do positive feedback loops always end in a counterbalancing negative
feedback?

Because if they didn't, they'd continue until they hit one.

------
Estragon
Why are our personal reproductive choices so rarely informed by these
Malthusian dynamics, let alone by the enormous personal burden involved in
raising children? Because a nation/ethnicity/clan/family whose culture is
comfortable with honest consideration of such questions does not grow as fast
as one in which reproduction is seen as a crucial to identity and survival
(both that of the group and that of the individual), and in which critical
consideration of reproductive behaviors is rejected as perverse, judgmental or
selfish.

~~~
rfugger
This is well-stated by Garrett Hardin in his classic 1968 essay "The Tragedy
of the Commons":

<http://dieoff.org/page95.htm>

~~~
billswift
Hardin overstated his case, for much better and more nuanced treatments, go to
Google Scholar and search for "Elinor Ostrom" "Tragedy of the commons". She
won the 2009 Nobel in economics, largely for her work in how "the commons"
really are managed.

------
tocomment
Here's another one. There can never be too much traffic, because if there
were, people would stop driving.

~~~
sp332
I heard that for over 100 years the actual speed of traffic in London was 9
miles per hour. If traffic started moving faster, more people drove. If it got
slower people wouldn't bother driving. Not sure if it's true or not but it
sounds plausible :)

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guth
Same thing with matter/antimatter, and "white flight" demographics. Also, the
more energy-efficient we make our technology, the _more_ energy we will use in
total.

Any tension not in a buffered solution will collapse to dominance by one-side.

This one, though: > Why can’t everyone just agree to a family-friendly,
40-hour workweek?

You can choose to opt-out of the rat race, and still be happy.

Some other too. Yes, to a first approximation, there are no easy problems (or
free lunches), so only attack problems you'd love to solve.

------
kfk
The OP has seriously misunderstood Malthus. Malthus never got to understand
that resources are relative and prices too. That's the same problem with
people saying we are doomed because oil is finishing: there will be
alternatives, prices will go so high to incentive real research on alternative
energies.

And the examples are mere examples of economic incentive, not even that clear
if you ask me. But then, what do I know, I only studied this stuff.

------
zem
this one (from the comments) i'd truly never thought of before:

> Why are so many people having to get fertility treatment to have children?
> Because if they stayed fertile longer, they’d put off having children even
> more.

------
adavies42
why do people repost three-year-old articles? because it's easier than finding
new ones saying the same thing.

this is like anthropic reasoning--always true, rarely useful.

~~~
gojomo
Why would a 'new [article] saying the same thing' be any better?

Aaronson has a parallel post about Anthropicisms, which seems to share your
skepticism about their value:

<http://www.scottaaronson.com/blog/?p=101>

For the 'Malthusianisms', I'd agree the name isn't exactly right, and I could
quibble with his specific examples. But the observation that things are in
their current and often 'sucky' state because some balance between tensions
has been reached is often useful.

It can help us get past frustration or superficial ranting about a situation,
to investigating the real forces at work. And, while some could take from this
analysis fatalism, I think it instead highlights what's necessary to be
effective. Simply tugging a little in the direction of one of the existing
forces is rarely the best path to change. You've got to approach such
dynamically-balanced situations from an oblique angle, and apply other
forces/insights to jump it to a new equilibrium.

