This multiplicative difficulty leading to the need for greater and greater
precision in assumptions can be illustrated with the following simple exercise
concerning the prediction of the movements of billiard balls on a
table. I use the example as computed by the mathematician Michael Berry.
If you know a set of basic parameters concerning the ball at rest, can compute
the resistance of the table (quite elementary), and can gauge the
strength of the impact, then it is rather easy to predict what would happen
at the first hit. The second impact becomes more complicated, but possible;
you need to be more careful about your knowledge of the initial
states, and more precision is called for. The problem is that to correctly
compute the ninth impact, you need to take into account the gravitational
pull of someone standing next to the table (modestly, Berry's computations
use a weight of less than 150 pounds). And to compute the fifty-sixth
impact, every single elementary particle of the universe needs to be present
in your assumptions! An electron at the edge of the universe, separated
from us by 10 billion light-years, must figure in the calculations, since it
exerts a meaningful effect on the outcome. Now, consider the additional
burden of having to incorporate predictions about where these variables
will be in the future. Forecasting the motion of a billiard ball on a pool
table requires knowledge of the dynamics of the entire universe, down to
every single atom! We can easily predict the movements of large objects
like planets (though not too far into the future), but the smaller entities
can be difficult to figure out—and there are so many more of them.
Note that this billiard-ball story assumes a plain and simple world; it
does not even take into account these crazy social matters possibly endowed
with free will. Billiard balls do not have a mind of their own.
Nor does our example take into account relativity and quantum effects.
Nor did we use the notion (often invoked by phonies) called the "uncertainty
principle." We are not concerned with the limitations of the precision
in measurements done at the subatomic level. We are just dealing
with billiard balls!
In a dynamical system, where you are considering more than a ball on
its own, where trajectories in a way depend on one another, the ability to
project into the future is not just reduced, but is subjected to a fundamental
limitation. Poincaré proposed that we can only work with qualitative
HOW TO LOOK FOR B I R D POOP 1 79
matters—some property of systems can be discussed, but not computed.
You can think rigorously, but you cannot use numbers. Poincaré even invented
a field for this, analysis in situ, now part of topology. Prediction
and forecasting are a more complicated business than is commonly accepted,
but it takes someone who knows mathematics to understand that.
To accept it takes both understanding and courage.
In the 1960s the MIT meteorologist Edward Lorenz rediscovered Poincaré's
results on his own—once again, by accident. He was producing a
computer model of weather dynamics, and he ran a simulation that projected
a weather system a few days ahead. Later he tried to repeat the same
simulation with the exact same model and what he thought were the
same input parameters, but he got wildly different results. He initially attributed
these differences to a computer bug or a calculation error. Computers
then were heavier and slower machines that bore no resemblance to
what we have today, so users were severely constrained by time. Lorenz
subsequently realized that the consequential divergence in his results arose
not from error, but from a small rounding in the input parameters. This
became known as the butterfly effect, since a butterfly moving its wings in
India could cause a hurricane in New York, two years later. Lorenz's findings
generated interest in the field of chaos theory.
Naturally researchers found predecessors to Lorenz's discovery, not
only in the work of Poincaré, but also in that of the insightful and intuitive
Jacques Hadamard, who thought of the same point around 1898, and
then went on to live for almost seven more decades—he died at the age
of ninety-eight.*
They Still Ignore Hayek
Popper and Poincaré's findings limit our ability to see into the future, making
it a very complicated reflection of the past—if it is a reflection of the
past at all. A potent application in the social world comes from a friend of
Sir Karl, the intuitive economist Friedrich Hayek. Hayek is one of the rare
celebrated members of his "profession" (along with J . M. Keynes and
G.L.S. Shackle) to focus on true uncertainty, on the limitations of knowledge,
on the unread books in Eco's library.
In 1974 he received the Bank of Sweden Prize in Economic Sciences in
* There are more limits I haven't even attempted to discuss here. I am not even bringing
up the class of incomputability people call NP completeness.
1 8 0 WE J U S T C A N ' T P R E D I CT
Memory of Alfred Nobel, but if you read his acceptance speech you will
be in for a bit of a surprise. It was eloquently called "The Pretense of
Knowledge," and he mostly railed about other economists and about the
idea of the planner. He argued against the use of the tools of hard science
in the social ones, and depressingly, right before the big boom for these
methods in economics. Subsequently, the prevalent use of complicated
equations made the environment for true empirical thinkers worse than it
was before Hayek wrote his speech. Every year a paper or a book appears,
bemoaning the fate of economics and complaining about its attempts to
ape physics. The latest I've seen is about how economists should shoot for
the role of lowly philosophers rather than that of high priests. Yet, in one
ear and out the other.
For Hayek, a true forecast is done organically by a system, not by fiat.
One single institution, say, the central planner, cannot aggregate knowledge;
many important pieces of information will be missing. But society as
a whole will be able to integrate into its functioning these multiple pieces
of information. Society as a whole thinks outside the box. Hayek attacked
socialism and managed economies as a product of what I have called nerd
knowledge, or Platonicity—owing to the growth of scientific knowledge,
we overestimate our ability to understand the subtle changes that constitute
the world, and what weight needs to be imparted to each such change.
He aptly called this "scientism."
This disease is severely ingrained in our institutions. It is why I fear governments
and large corporations—it is hard to distinguish between them.
Governments make forecasts; companies produce projections; every year
various forecasters project the level of mortgage rates and the stock market
at the end of the following year. Corporations survive not because they
have made good forecasts, but because, like the CEOs visiting Wharton I
mentioned earlier, they may have been the lucky ones. And, like a restaurant
owner, they may be hurting themselves, not us—perhaps helping us
and subsidizing our consumption by giving us goods in the process, like
cheap telephone calls to the rest of the world funded by the overinvestment
during the dotcom era. We consumers can let them forecast all they want
if that's what is necessary for them to get into business. Let them go hang
themselves if they wish.
As a matter of fact, as I mentioned in Chapter 8, we New Yorkers are
all benefiting from the quixotic overconfidence of corporations and
restaurant entrepreneurs. This is the benefit of capitalism that people discuss
the least.
HOW TO LOOK FOR B I R D POOP 1 81
But corporations can go bust as often as they like, thus subsidizing us
consumers by transferring their wealth into our pockets—the more bankruptcies,
the better it is for us. Government is a more serious business and
we need to make sure we do not pay the price for its folly. As individuals
we should love free markets because operators in them can be as incompetent
as they wish.
The only criticism one might have of Hayek is that he makes a hard and
qualitative distinction between social sciences and physics. He shows that
the methods of physics do not translate to its social science siblings, and he
blames the engineering-oriented mentality for this. But he was writing at a
time when physics, the queen of science, seemed to zoom in our world. It
turns out that even the natural sciences are far more complicated than that.
He was right about the social sciences, he is certainly right in trusting hard
scientists more than social theorizers, but what he said about the weaknesses
of social knowledge applies to all knowledge. All knowledge.
Why? Because of the confirmation problem, one can argue that we
know very little about our natural world; we advertise the read books and
forget about the unread ones. Physics has been successful, but it is a narrow
field of hard science in which we have been successful, and people
tend to generalize that success to all science. It would be preferable if we
were better at understanding cancer or the (highly nonlinear) weather
than the origin of the universe.
How Not to Bo a Nerd
Let us dig deeper into the problem of knowledge and continue the comparison
of Fat Tony and Dr. John in Chapter 9. Do nerds tunnel, meaning,
do they focus on crisp categories and miss sources of uncertainty? Remember
from the Prologue my presentation of Platonification as a top-down
focus on a world composed of these crisp categories. *
Think of a bookworm picking up a new language. He will learn, say,
Serbo-Croatian or !Kung by reading a grammar book cover to cover, and
memorizing the rules. He will have the impression that some higher grammatical
authority set the linguistic regulations so that nonlearned ordinary
people could subsequently speak the language. In reality, languages grow
* This idea pops up here and there in history, under different names. Alfred North
Whitehead called it the "fallacy of misplaced concreteness," e.g., the mistake of
confusing a model with the physical entity that it means to describe.
1 8 2 WE J U S T C A N ' T PREDICT
organically; grammar is something people without anything more exciting
to do in their lives codify into a book. While the scholastic-minded will
memorize declensions, the a-Platonic nonnerd will acquire, say, Serbo-
Croatian by picking up potential girlfriends in bars on the outskirts of
Sarajevo, or talking to cabdrivers, then fitting (if needed) grammatical
rules to the knowledge he already possesses.
Consider again the central planner. As with language, there is no grammatical
authority codifying social and economic events; but try to convince
a bureaucrat or social scientist that the world might not want to
follow his "scientific" equations. In fact, thinkers of the Austrian school,
to which Hayek belonged, used the designations tacit or implicit precisely
for that part of knowledge that cannot be written down, but that we
should avoid repressing. They made the distinction we saw earlier between
"know-how" and "know-what"—the latter being more elusive and
more prone to nerdification.
To clarify, Platonic is top-down, formulaic, closed-minded, self-serving,
and commoditized; a-Platonic is bottom-up, open-minded, skeptical, and
empirical.
The reason for my singling out the great Plato becomes apparent with
the following example of the master's thinking: Plato believed that we
should use both hands with equal dexterity. It would not "make sense"
otherwise. He considered favoring one limb over the other a deformation
caused by the "folly of mothers and nurses." Asymmetry bothered him,
and he projected his ideas of elegance onto reality. We had to wait until
Louis Pasteur to figure out that chemical molecules were either left- or
right-handed and that this mattered considerably.
One can find similar ideas among several disconnected branches
of thinking. The earliest were (as usual) the empirics, whose bottom-up,
theory-free, "evidence-based" medical approach was mostly associated
with Philnus of Cos, Serapion of Alexandria, and Glaucias of Tarentum,
later made skeptical by Menodotus of Nicomedia, and currently wellknown
by its vocal practitioner, our friend the great skeptical philosopher
Sextus Empiricus. Sextus who, we saw earlier, was perhaps the first to discuss
the Black Swan. The empirics practiced the "medical art" without relying
on reasoning; they wanted to benefit from chance observations by
making guesses, and experimented and tinkered until they found something
that worked. They did minimal theorizing.
Their methods are being revived today as evidence-based medicine,
after two millennia of persuasion. Consider that before we knew of bacteHOW
TO LOOK FOR B I R D POOP 1 83
ria, and their role in diseases, doctors rejected the practice of hand washing
because it made no sense to them, despite the evidence of a meaningful decrease
in hospital deaths. Ignaz Semmelweis, the mid-nineteenth-century
doctor who promoted the idea of hand washing, wasn't vindicated until
decades after his death. Similarly it may not "make sense" that acupuncture
works, but if pushing a needle in someone's toe systematically produces
relief from pain (in properly conducted empirical tests), then it
could be that there are functions too complicated for us to understand, so
let's go with it for now while keeping our minds open.
Academic Libertarianism
To borrow from Warren Buffett, don't ask the barber if you need a
haircut—and don't ask an academic if what he does is relevant. So I'll end
this discussion of Hayek's libertarianism with the following observation.
As I've said, the problem with organized knowledge is that there is an occasional
divergence of interests between academic guilds and knowledge
itself. So I cannot for the life of me understand why today's libertarians do
