[Paleopsych] Robin Hanson: The Next Really Big Enormous Thing
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Sat Oct 9 23:48:24 UTC 2004
Robin Hanson: The Next Really Big Enormous Thing
Assistant Professor of Economics, George Mason University
(read his bio)
A postcard summary of life, the universe and everything might go as
follows. The universe appeared and started expanding. Life appeared
somewhere and then on Earth began making larger and smarter animals.
Humans appeared and became smarter and more numerous, by inventing
language, farming, industry, and computers.
The events in this summary are not evenly distributed over the history
of the universe. The first events are relatively evenly distributed:
the universe started fourteen billion years ago, life appeared by four
billion years ago, and on Earth animals started growing larger and
smarter about half a billion years ago. But the other events are very
recent: our species appeared two million years ago, farming started
ten thousand years ago, industry started two hundred years ago, and
computers started a few decades ago.
Do we over-emphasize these recent events relative to their fundamental
importance, because they are about our species and us? Are these
events just arbitrary markers, chosen from thousands in a long history
of relatively continuous change?
I think not, and here is why: most of these events separate a chain of
distinct exponential growth modes. (Exponential growth is where a
quantity doubles after some time duration, then continues to double
again and again after similar durations.) The growth rates of these
modes have varied enormously.
The slowest growth mode started first. Our fourteen billion year old
universe is expanding, and that expansion is becoming exponential due
to a mysterious "dark energy." The distance between the galaxies is
predicted to double every ten billion years.
We don't know enough about the history of non-animal life in the
universe to identify its growth rates, but we can see that for the
last half billion years the size of animals on Earth has grown
exponentially. While the size of the typical animal is largely
unchanged, the variation among animal size has greatly increased.
Because of this, the mass of the largest animal has doubled about
every seventy million years, and the mass of the largest brain has
doubled about three times every hundred million years. So the largest
brains have doubled about three hundred times faster than the distance
Humans (really "our human-like ancestors") began with some of the
largest brains around, and then tripled their size. Those brains, and
the innovations they embodied, seem to have enabled a huge growth in
the human niche - it supported about ten thousand humans two million
years ago, but about four million humans ten thousand years ago.
While data is scarce, this growth seems exponential, doubling about
every two hundred and twenty five thousand years, or one hundred and
fifty times faster than animal brains grew. (This growth rate for the
human niche is consistent with faster growth for our ancestors -
groups might kill off other groups to take over the niche.)
About ten thousand years ago, those four million humans began to
settle and farm, instead of migrating to hunt and gather. The human
population on Earth then began to double about every nine hundred
years, or about two hundred and fifty times faster than hunting humans
Since the industrial revolution began a few hundred years ago, the
human population has grown even faster. Before the industrial
revolution total human wealth grew so slowly that population quickly
caught up, keeping wealth per person at a near subsistence level. But
in the last century or so wealth has grown faster than population,
allowing for great increases in wealth per person.
Economists' best estimates of total world product (average wealth per
person times the number of people) show it to have been growing
exponentially over the last century, doubling about every fifteen
years, or about sixty times faster than under farming. And a model of
the whole time series as a transition from a farming exponential mode
to an industry exponential mode suggests that the transition is not
over yet - we are slowly approaching a real industry doubling time of
about six years, or one hundred and fifty times the farming growth
A revised postcard summary of life, the universe, and everything,
therefore, is that an exponentially growing universe gave life to a
sequence of faster and faster exponential growth modes, first among
the largest animal brains, then for the wealth of human hunters, then
farmers, and then industry. It seems that each new growth mode starts
when the previous mode reaches a certain enabling scale. That is,
humans may not grow via culture until animal brains are large enough,
farming may not be feasible until hunters are dense enough, and
industry may not be possible until there are enough farmers.
Notice how many "important events" are left out of this postcard
summary. Language, fire, writing, cities, sailing, printing presses,
steam engines, electricity, assembly lines, radio, and hundreds of
other "key" innovations are not listed separately here. You see, most
big changes are just a part of some growth mode, and do not cause an
increase in the growth rate. While we do not know what exactly has
made growth rates change, we do see that the number of such causes so
far can be counted on the fingers of one hand.
While growth rates have varied widely, growth rate changes have been
remarkably consistent -- each mode grew from one hundred and fifty to
three hundred times faster than its predecessor. Also, the recent
modes have made a similar number of doublings. While the universe has
barely completed one doubling time, and the largest animals grew
through sixteen doublings, hunting grew through nine doublings,
farming grew through seven and a half doublings, and industry has so
far done a bit over nine doublings.
This pattern explains event clustering - transitions between faster
growth modes that double a similar number of times must cluster closer
and closer in time. But looking at this pattern, I cannot help but
wonder: are we in the last mode, or will there be more?
If a new growth transition were to be similar to the last few, in
terms of the number of doublings and the increase in the growth rate,
then the remarkable consistency in the previous transitions allows a
remarkably precise prediction. A new growth mode should arise sometime
within about the next seven industry mode doublings (i.e., the next
seventy years) and give a new wealth doubling time of between seven
and sixteen days. Such a new mode would surely count as "the next
really big enormous thing."
The suggestion that the world economy will soon double every week or
two seems so far from ordinary experience as to be, well, "crazy." Of
course similar predictions made before the previous transitions would
have seemed similarly crazy. Nevertheless, it is hard to take this
seriously without at least some account of how it could be possible.
Now we cannot expect to get a very detailed account. After all, most
economics has been designed to explain the actual social worlds that
we have seen so far, and not all the possible social worlds that might
exist. Even then we are still pretty ignorant about the causes of the
previous transitions. But we do want at least a sketchy account.
It turns out to be hard to create such an account using things like
space colonization or new energy sources, mainly because we now pay
only a small fraction of our budget on things like land and energy.
But we pay seventy percent of world income for human labor, so
anything that can lower this cost can have a huge impact. I am thus
drawn to consider scenarios involving robotics or artificial
While machines have sometimes displaced human workers, they have much
more often helped humans be more productive at tasks that machines
cannot do. Machines have thus on net raised the value, and hence the
cost, of human labor. And because people are essential, the limited
rate of human population growth has limited the economic growth rate.
Once we have machines that can do almost all the tasks that people can
do, however, this picture changes dramatically. Since the number of
machines can grow as fast as the economy needs them, human population
growth no longer limits economic growth. In fact, simple growth models
which assume no other changes can easily allow a new doubling time of
a month, a week, or even less.
Now admittedly, progress in robotics and artificial intelligence has
been slow over the decades, primarily because it is so hard to write
the software. And at these rates it could be centuries before we have
software that can do almost all tasks that people do. The "upload"
approach, however, of scanning human brains then simulating them in
detail in computers, seems likely to succeed within the next half
century or so.
The transition from farming to industry seems to have been more
gradual than the transition from hunting to farming. Even such a
"gradual" transition, however, would be very dramatic. Assume that a
new transition was as gradual as the one to industry, and that the
world economic growth rate was six percent in both 2039 and 2040, plus
or minus a typical yearly fluctuation of half a percent.
If so, then in 2041, the increase in the growth rate might be the size
of a typical fluctuation, and then in 2042 the growth rate would be a
noticeably different eight percent. Growth would then be 14% in 2043,
50% in 2044, 150% in 2045, and 500% in 2046. Within five years the
change would go from barely noticeable to overwhelming.
This is disturbing because human wages should fall quickly with the
falling price of machines. So while humans who owned shares in the
firms that made machines would get very rich, those whose only source
of income was their labor could die of starvation. And if people wait
to see the transition happen before they believe it is real, they
might not have time to arrange for other sources of income.
If we stand back from all the big events and innovations we have seen
in the last century and look at the overall world economic growth
rate, it seems surprisingly steady. All those events and innovations
contribute to growth, but have not much changed the overall growth
rate. From this, one might expect such steady growth to continue for a
Looking further back in time, however, we see that once in a while
something has changed the growth rate by enormous factors in a
relatively short time. We might do well to not ignore such a speeding
freight train until it actually hits us.
For more information see my papers:
Long-Term Growth As A Sequence of Exponential Modes
Economic Growth Given Machine Intelligence
If Uploads Come First
This essay is original and was specifically prepared for publication
at Future Brief. A brief biography of Dr. Hanson can be found at our
main Commentary page. Other essays written by Dr. Hanson can be
found at his web site. Other websites are welcome to link to this
essay, with proper credit given to Future Brief and Dr. Hanson. This
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