
Our greatest shortcoming is our inability to understand the exponential function - itistoday
http://www.youtube.com/watch?v=F-QA2rkpBSY&feature=related
======
netcan
A lot to learn from this video about explaining things:

\- Know your stuff. It's obvious he's been over all of this hundreds of times.

\- Figure out great analogies and other aids. Part 3: 5:20 he makes an analogy
out of multiplying bacteria in a bottle that fill it in an hour to show us at
what point of the exponential function you notice your in one. It's got two
parts and is very effective. It allows him to say things like "5 minutes
before the bottle is full."

\- Introduce your aids gradually and keep using them. Make clever decisions
about your aids and make sure they accumulate to a powerful toolset. After
that analogy which all the time he introduces the analogy above he has:

    
    
      - A trick for calculating doubling time 70/annual growth in %
      - A graph
      - A table 
      - An example (Boulder) that he keeps running scenarios on. 
      - The bacteria analogy 
      

By the time he's 20-30 minutes into a lecture, this guy has a very powerful
vocabulary built up. He can take something like oil consumption and examine it
with you very quickly using these tools. The bacteria in a bottle analogy is a
great example of this. Once he's explained it (kind of hard) and practised it
once or twice, he can say _"What time is it?"_ and immediately have his
audience understand something relatively complex. .

------
mhartl
Before people freak out about exponential growth, please consider John
McCarthy's Slogan. (Yes, _that_ John McCarthy; Lisp isn't the only thing he's
done.)

    
    
      He who refuses to do arithmetic is doomed to talk nonsense.
    

<http://www-formal.stanford.edu/jmc/progress/index.html>

Based on reactions to this video (among other things), I'd add Hartl's
Counterpoint:

    
    
      Just because you're willing to do arithmetic doesn't 
      mean you're not talking nonsense.
    

In case you're wondering _why_ you shouldn't freak out, I offer you this:
<http://en.wikipedia.org/wiki/Logistic_function>

~~~
wazoox
Huh. This guy is simply making the very basic point that politicians,
economists and bankers selling us "growth" as a solution to unemployment,
debt, etc are plainly lying. Growth (population, GDP, energy availability,
etc) will stop at some point. An economy that relies entirely on growth to
merely function is doomed to fail spectacularly at some point in time.

~~~
dagw
I agree that population growth cannot go on forever (although I consider
doubling the current number quite likely). However I see no reason why energy
availability can't keep growing for many many centuries to come. We aren't
tapping the full potential of nuclear fission, to say nothing about fusion.
Things like solar energy in all its variations is also a source we basically
aren't using at all. Give us 50-100 years an we'll no doubt come up with some
new source of energy we haven't even considered yet.

~~~
wazoox
> However I see no reason why energy availability can't keep growing for many
> many centuries to come. We aren't tapping the full potential of nuclear
> fission, to say nothing about fusion.

Nuclear fission is currently on decline. We aren't even building enough power
plants to maintain its output, nor are we likely to do so in the next 20 to 30
years. Industrial nuclear fusion is decades away, probably a century.

From the 18th century onwards, we went from tapping ever better energy sources
(denser, lighter): animal power, coal, oil. There aren't any better energy
source than oil available now, or in the foreseeable future. At some point,
we'll have to do with /less/.

~~~
Daniel_Newby
"At some point, we'll have to do with /less/."

This part of the long business cycle always produces a lot of arguments for
austerity. So far they have always turned out to be spectacularly wrong.

"Nuclear fission is currently on decline."

Nuclear power, both fission and fusion, is currently in a renaissance and we
appear to be laying the groundwork for the next stage of advances: gas- and
metal-cooled reactors, superconductors, mechanical compression systems,
reliable mode-locked lasers, dielectric wall and wake field particle
accelerators, electronics that can do real-time gigahertz feedback, etc.

When the next long expansion gets into full swing, I predict that the nuclear
logjam will break loose.

"There aren't any better energy source than oil available now, or in the
foreseeable future."

There's a lot of solar power in space. _A lot_. And literal mountains of
metal, richer than the best terrestrial ores and pre-smelted too. At some
point technology will tip the profit margin positive on exploiting it.

~~~
wazoox
> So far they have always turned out to be spectacularly wrong.

So far, there weren't 7 billions humans neither.

> Nuclear power, both fission and fusion, is currently in a renaissance

Absolutely not. This is GE and AREVA PR, but doesn't reflect the truth. We
aren't building enough nuclear plants now to compensate for the future closing
of the old ones. The numbers aren't even ramping up fast enough. As time goes
by, there will be less and less active nuclear plants.

Fusion research is blooming, but it didn't make much progress, particularly
compared to the huge effort (see ITER).

> There's a lot of solar power in space. A lot. And literal mountains of
> metal, richer than the best terrestrial ores and pre-smelted too. At some
> point technology will tip the profit margin positive on exploiting it.

This is science-fiction. I'm pretty close to say this is complete BS. "Space
ore" simply can't happen unless you find the way to harvest the power from
some magic ponies yet to discover.

~~~
dagw
I totally agree that we aren't building enough nuclear power plants, but that
is purely for political reasons. The research is still happening and once
there is a change in the political climate we'll be able to ramp up nuclear
power over a few decades.

Also if we look back at the past 1000 (or even just 100) years of human
history, we've been pretty good at discovering and harvesting 'magic ponies'
of all shapes and sizes.

~~~
wazoox
> we'll be able to ramp up nuclear power over a few decades.

Maybe if thorium comes on the radar.

> we've been pretty good at discovering and harvesting 'magic ponies' of all
> shapes and sizes.

Well, not that much. By the end of the roman republic, most of what made the
industrial revolution possible was available, but it didn't happen until 18
centuries later.

~~~
mbreese
The ancient Greeks even had an initial stream engine, but never put it to
practical use, relegating it to parlor/temple game.

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

~~~
wazoox
That's what I mean : they had the ability to go to industrial age, they lacked
the will, the impulse.

~~~
joeyo
Also, they had slavery.

------
jluxenberg
Neat math trick from the video:

70 / x = number of years of constant growth required for a quantity to double
given that it grows at x percent

The example used in the video: if the price of lift tickets goes up by 7% per
year, in 10 years, that price will double.

(and actually, the constant 70 is an approximation, the actual constant is ln
(2) * 100)

~~~
chaosmachine
It's also a useful way to tell when your investments will double in value. 5%
interest: 70/5 = 14 years to double your money.

~~~
Luc
It also works for inflation or other yearly recurring charges. Those small
percentages add up quickly - at 3% inflation and 2% charges the value of your
investment in today's dollars/euros will halve in 14 years. Yikes!

~~~
eru
Yes, but why use it, when you can do a logarithm?

~~~
sesqu
Few people can do logarithms in their heads - and those that can, usually do
it using similar tricks. I realize that "doing math in your head" is well on
the decline, but it is pretty essential for speedy approximations, which are
what many decisions tend to be based on.

~~~
eru
Yes. I was more on the line of suggesting taking out your calculator, if you
want to know when your investment doubles.

------
jackowayed
I've thought about his point that lowering the death rate makes the problem of
population growth worse a lot, especially in the context of Africa and the
like.

"Oh they're starving because they get almost no rain, so that land really
shouldn't support anywhere near as many people as are there. Let's give them
food aid."

10 years elapse, and say they're getting 7% per year growth thanks to food aid
keeping them from starving, lack of contraception, etc.

"Oh, there's twice as many of them now, so they're starving despite our
current food aid. Double the food aid!"

Repeat until you realize that you can't double the food aid forever.

~~~
ihodes
The trick is realizing that the last 3 words of your third sentence are the
most important part of your slightly offensive post. That, and education.

Starving a people until they can eat off of the barren land they inhabit is
certainly one way of taking care of the problem. Educating them on the merits
of contraceptives, and teaching them how to use their land to greater effect
is another.

~~~
mistermann
Africa is not a barren land, much of Africa is perfect for farming. Much of
Africa is not "perfect" for farming, but well good enough. However, if you
have external nations bringing you food for free, why the hell would you go
through the trouble to grow a crop, it's seriously hard work!

And, if you're in the part of Africa where growing crops is not
feasible....move?

~~~
skybrian
You realize that this isn't about renting a U-haul, right? It's about
traveling, on foot or by public transportation, to somewhere where you don't
own any land, don't speak the language, and don't know anyone. In other words,
to become a refugee. There are plenty of people like that already, but they
tend to move to the cities.

------
prodigal_erik
I'm not usually a fan of long talking-head videos but this was absolutely
worthwhile. What's most chilling is the story of the bottle and the bacteria,
and the realization that somehow finding a whole new planet would only tide us
over for a couple more generations, after which we'd need two more....

~~~
zemaj
But it's all considered in a vacuum. Even though the majority of the
population don't understand the problem, this is ok. We have an economic
system that benefits those who predict impending needs and place themselves in
situations to provide for them.

Take a look at the green industry ramping up. In the not too distance future,
I think most of us here expect oil replacement to be highly profitable.

I disagree with these doomsday predictions from pure arithmetic. It seems to
me that the reverse is true - exponential "problems" provide the core drive
for our economy. What drives the entire start-up industry? I'd say it's
identifying profitable exponential growth scenarios and providing for them. To
me, this explains how primarily capitalist countries tend toward stability,
until them become strangled by ever increasing regulation (that's not to say
I'm against regulation in general, but I think we need to be as proactive
about removing it as we are about adding it [wow, I went off topic there]).

~~~
skybrian
Yes, many people are working on solutions, but I think the point is that for
green industry to succeed, growth in energy consumption has to actually stop,
and preferably reverse. It's good to be clear about about the goal.

~~~
ars
That's not a good goal. And besides not being good, it's also impossible if
you are trying to avoid mass catastrophe.

Economic development directly correlates with energy use. To reduce energy use
you would either need a massive depression, or for a lot of people to die.

But the news isn't all bad - nuclear power is both green, and sufficiently
available to allow us to continue energy growth. So I would make that the
goal.

~~~
skybrian
In the short term, sudden changes in energy consumption are very disruptive.
(For example, see gas prices and the auto industry last year.) But a longer-
term, gradual shift towards less energy usage need not be.

------
jackowayed
The best illustration of the concept, imo, is that with sustained 1.3%/year
world population growth, we'll reach a population density of 1 person per
square _meter_ of land in only 780 years.

~~~
redorb
give me some context; how many meters per a person are we at currently? / Then
give me some focus; what will it be at in my life span... 50 years?

~~~
kalid
Just for fun, I made a quick calc for you: <http://tinyurl.com/3xl32bx>

In 50 years at 1.3% growth we'll basically double our population, and go from
about 8000 m^2 per person to 4000 m^2 per person. After 780 years, the growth
starts adding up, you can play with the numbers.

~~~
jackowayed
Wow, instacalc is pretty awesome.

------
pmiller2
People don't understand exponentials very well because human perception is
scaled logarithmically. For example, both the apparent magnitude scale for
celestial objects and the loudness scale for sounds (measured in decibels) are
logarithmic.

~~~
raimondious
If our perception is scaled logarithmically, wouldn't that give us an
intuitive sense for exponentials?

------
aresant
Part of the problem is that the distant future to humans is never any further
out than ~70 years - eg our lifespans.

Exponential resource waste, population growth, etc doesn't become a non-
survivable event for a few more generations - at that point we may actually
start to see realistic change.

------
jwegan
Definitely worth watching the entire series, but for those looking to save
time: the first video covers the main point and the subsequent videos in the
series just reinforce its significance.

------
indrax
I think we actually do have a deep implicit understanding of the exponential
function, and THAT may be our greatest shortcoming. We don't understand it
precisely, and we don't intuitively relate to "4^x".

But we very intuitively get things like "really big changes will come from
small things" And we rate highly getting a seemingly small increase in
personal ability. This is why videos like this can capture our attention at
all. It seems like a basic ability to recognize and reason approximately about
exponential growth is required to do agriculture.

I think this is why we like RPG's and katamari damacy, and talking about peak
oil.

I think that this mental flag also makes us extremely sensitive of people
'from the wrong tribe' being in our area.

In short, I think that we were surrounded by exponential functions in our
ancestral environment, and developed an ability to recognize them and see them
as very important, with out really knowing what they are.

------
iamwil
I haven't gotten back into the habit of watching lectures in a while, but this
was one of the best ones I've watched in a long time. Thought it was super
cheesy at first, and didn't think I was going to keep watching, but it kept me
rapt the entire time.

------
ModelCitizen
A note on the rest of the series: He spends the remaining time outlining some
impending Malthusian catastrophe / peak oil scenario. For a counterpoint,
check out anything by Julian Simon.

~~~
skybrian
Actually, he doesn't think much of Julian Simon and says why.

~~~
ModelCitizen
Which is why I offer Simon as a counterpoint.

Simon believed that there is more than simple arithmetic (as Bartlett calls
it) when it comes to growth. You have to throw something like technology into
the mix, which is difficult to predict.

The Simon-Erlich bet is a good, real-world illustration of their
disagreements.

~~~
rsheridan6
Ehrlich was a jackass who made hysterical predictions. In the 70s, he was
predicting an imminent Malthusian disaster - like this -
[http://www.paleofuture.com/blog/2007/7/18/the-population-
bom...](http://www.paleofuture.com/blog/2007/7/18/the-population-bomb-
scenario-3-1970.html)

That's a long way from Bartlett.

Don't take Ehrlich as a spokesman for anybody who believes in limits to
growth.

------
madair
In part three he brilliantly draws a distinction between the objective
sciences and others and subtly, if I'm understanding correctly, critiques a
proponent of uncontrolled population grown by pointing out that the proponents
degree from the same university is not a degree in "mathematics, in science,
nor in engineering".

Feynman made explicit observations on this topic, quite critical ones, if I
remember right.

------
KingOfB
Anyone find any good graphs about population growth? I asked wolframalpha and
was pretty dissapointed, google found this article which I found interesting.
Second graph in particular. Seems at 1000 and 1400 there were some drastic
growth rate shifts.

<http://www.theoildrum.com/story/2005/12/18/1387/0641>

~~~
henrikschroder
From another comment:

[http://www.gapminder.org/videos/what-stops-population-
growth...](http://www.gapminder.org/videos/what-stops-population-growth/)

You can play with the data here:
[http://www.gapminder.org/world/#$majorMode=chart$is;shi=t;ly...](http://www.gapminder.org/world/#$majorMode=chart$is;shi=t;ly=2003;lb=f;il=t;fs=11;al=30;stl=t;st=t;nsl=t;se=t$wst;tts=C$ts;sp=6;ti=1950$zpv;v=0$inc_x;mmid=XCOORDS;iid=phAwcNAVuyj0TAlJeCEzcGQ;by=ind$inc_y;mmid=YCOORDS;iid=phAwcNAVuyj2tPLxKvvnNPA;by=ind$inc_s;uniValue=8.21;iid=phAwcNAVuyj0XOoBL_n5tAQ;by=ind$inc_c;uniValue=255;gid=CATID0;by=grp$map_x;scale=lin;dataMin=0.7454;dataMax=8.6$map_y;scale=lin;dataMin=22;dataMax=84$map_s;sma=49;smi=2.65$cd;bd=0$inds=;example=59)

------
Tycho
I've always had this idea in my mind that the 'legendary failure rate of IT
projects' is best explained in terms of an exponential increase in points of
failure (or even just points of activity) when you deal with computer systems.
Are there any famous papers that flesh out this idea? Anyone?

------
tibbon
I'm curious what the average price of gall bladder surgery is now. In it his
students project 25K by 2000, which we are obviously quite a way past. If
you're uninsured, this amount sounds about right likely these days.

Great video. I'm on part 2 and I'll finish the rest in the morning.

~~~
Empact
The HealthCare Blue Book tells an interesting story:

* $16,435 for traditional gall bladder removal, somewhat below the estimate [http://healthcarebluebook.com/page_Results.aspx?id=75&da...](http://healthcarebluebook.com/page_Results.aspx?id=75&dataset=MD)

* $6,934 for the modern minimally invasive equivalent, far below the estimate [http://healthcarebluebook.com/page_Results.aspx?id=74&da...](http://healthcarebluebook.com/page_Results.aspx?id=74&dataset=MD)

More evidence that projecting trends without considering technical progress is
bound to result the sort of overly pessimistic results that Malthus made
famous.

For example, Dr. Bartlett's two-column view on population assumes that people
will need some certain number of square feet of land. But why wouldn't we
build up, ala NYC? Or settle the ocean (<http://seasteading.org/>)? Or
colonize the stars? Or perhaps even transfer our consciousness to some more
efficient representation?

Yes, exponential growth presents problems, but exponential progress in
technology has the power to solve them. That's where we (and others like us)
come in.

~~~
chaosmachine
If you watch the video, you'll see why "find more land" isn't a sustainable
solution. Ultimately, population growth just needs to stabilize at 0% to solve
the running out of space problem (but not the running out of resources
problem, which is where technology is more likely to help).

------
chrischen2
Well one benefit of increasing population is that we increase the chances of
geniuses being born, and increase the diversity of the population.

~~~
JBiserkov
There's an old joke that says:

    
    
      The intellect of the planet is a constant, the population is increasing. 
    

genius != intelligence, but still :)

