CONFIRMATION SHMONFIRMATION!

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CONFIRMATION SHMONFIRMATION!
I
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50
UMBERTO
ECO'S
ANflLlBllARY
Now, there are other themes arising from our blindness to the Blaek
Swan:
a. We foeus on preseleeted segments of the seen and generalize from
it to the unseen: thc error of confirmation.
b. We fool ourselves with stories that cater to our Platonic thirst for
distinct patterns: the narrative fallacy.
e. We behave as if the Blaek Swan does not exist: human nature is not
Cha
pIe
r Flve
CONFIRMATION
SHMONFIRMATION!
programmed for Blaek Swans.
d. What we see is not neeessarily al! that is there. History hides Black
Swans from us and gives us a mistaken idea about the odds of thcse
events: this is the distortion of silent evidenee.
e. We "tunnel": that is, we foeus on a few well-defined sources of uncertainty, on too specifie a list of Blaek Swans (at the expense of the
others that do not easily come to mind).
I have so much evidence-Can
1 will diseuss eaeh of the points in the next five ehapters. Then, in the
eonclusion of Part One, 1will show how, in effeet, they are the sarne topic.
Zoogles be (sometimes) Boogles?-
Corroboration shmorroboration-Popper's
idea
As much as it is ingrained in our habits and conventional wisdom, confirmation can be a dangerous error.
Assume 1 told you that 1 had evidence that the football player O. J.
Simpson (who was accused of killing his wife in the 1990s) was not a
criminal. Look, the other day 1 had breakfast with him and he didn't kill
, _r¡ybody. 1am serious, 1did not see him kill a single persono Wouldn't that
;' eonfirm his innocenee? If 1 said such a thing you. would certainly call a
',hrink, an ambulance, or perhaps even the police, sinee you might think
.. ~.hat 1 spent too much time in trading rooms or in cafés thinking about this
lack Swan topic, and that my logic may represent such an immediate
,e
dllnger
to society that 1 myself need to be loeked up immediately.
~
;('i
You would have the same reaction if 1 told you that 1 took a nap the
Othcr day on [he railroad trae k in New Rochelle, New York, and was not
klllcd. Hey, look at me, 1 am alive, 1 would say, and that is evidence that
lylng on train tracks is risk-free. Yet eonsider the following. Look again at
t'.l~llre 1 in Chapter 4; someone who observed the turkey's first thousand
~.IYs(but not the shock of the thousand and first) would tell you, and
[j,lllhtly so, that there is no evidence of the possibility of large events, i.e.,
---
52
UMBERTO
ECO'S
ANTlLlBRAIIY
Black Swans. You are likely to confuso
rhat staterncnr,
lady if you do not pay close atrention,
evidence of no possible Black Swans. Even though
logical distanee
mind,
berween the two assertions
now, if you manage
to remember
the seeond,
Black Suians. I call rhis eonfusion
menrs are not intercbangeable.
Such confusion
(but crucial),
rors, nor are professors
plicated
equations
!
I
, I
,I
I
I
I
I
I
I
¡,
all Moslems
is true, that 99 pereent
thousand.
overestimate
to trivial,
immune
Assume
mistake
lege. Yet another
elevator, This inability
simplify the
from the same confusion:
it.
are Moslems"
mean that
since there are more
"I never meanr
terrorists,
one in a
Moslem
Mili once complained.
round-trip
person
fallacy
the unfairness
of
areas in the Unired States have suffered
people are generally
is chronic:
of the object
with
our
bur they still
and sophisti-
,
1
depend on
what evolutionary
psycholo-
rhe evento The c1assroom
John Stuart
if you tell people that the
Logieal
problems
differently
ap-
in daily
even when it is exact, does not often lead to appropriate
if we do not pay attention,
plied professors
of statistics
t tistical questions,
even when we are experts.
tend to leave their brains
engage in the mosr trivial inferential
i
it, and how
surrounds
system.
is a do-
not on its
acrions beca use we tend to forget what we know, or forget how ro process
:1
"'.
.
is a quite
By domain-specific
our intuitions,
proached one way in the c1assroom might be treated
l¡fe. Indeed rhey are treated differently in daily life.
, " Itreets. In 1971, the psychologisrs
stupid.
OI
social-emotional
.~ cians, ir has been shown,
know better.
Conservative,"
our mode of thinking,
in which the matrer is presented,
registers
-:~ It properly
come frorn rheir ethnic
are not criminals,
by people who should
This problem
knowledge
logical merit, bur on rhe basis of which framework
ir
by close to fifty
to say that the Conserva ti ves are generally
meant to say that stupid
si de of town steps into the
transfer
main; real life is another, We reacr to a piece of information
you (unconsciously)
individual
even if rnost criminals
suffer from díscrimination
from the wrong
to autornarically
I mean thar our reactions,
gisrs cal! the "domain"
makes
drawn
most of rheir ethnic subgroup
on their SAT test might not make ir to eol-
cation from one situation to another, or from theory to practiee,
disturbing attribute of human nature.
Knowledge,
in urban
have
person can get very high scores on the SATs and still feel
a chill of fear when someone
This would
times!
subgroup,
swering this kind of question
the context
thousand
stereotypes-minorities
mtuinons
can make a big differ-
Are Nof AI/ 800g195
that the firsr staternent
the age of, say, fifteen and fifty) being a terrorist
see in this
Our staristical
Let us call it the domain speci{icity of our reactions.
(between
might
mconsequenrial,
in which these subtleties
Al! zoogles are boogles. You saw a boogle. 1s it a zoogle? Not necessarily,
since not al! boogles are zoogles, adolescents who make a mistake in an-
to them (com-
all rerrorists
are terrorists,
the odds of a randomly
The reader
Zoogle5
logical er-
our knowing
and only, say, ten thousand
So the logical
almost
110
wirh clarity of mind).
are Moslems.
of Moslems
than one billion Moslems
hundred
in your
oí a trivial, very trivial
happily
"almost
are terrorists."
15
not evolved for a habitat
ence.
here.
of terrorists
.001 percent
only about
partakes
do so without
Many people confuse the statement
with "alrnost
I
ar all, you will be
very hard, we are likely to unwitringly
It is worth a deeper examination
error here, but it
I
fallacy, since these sta te-
particularly
beca use our minds routinely
53
killers are toild animals and most wtld animals are killers. There is an
faet vast, the
there is proof of
we are not immune
do not tend to cohabit
Unless we concentrate
problem
the round-trip
and thinkers
r
SHMONFIRMATIONI
for the other, Ten days from
version-that
of the two statements
logical error-but
it isin
the firsr statement
inaccurate
particu-
that there is
will seem very narrow
so that one can be easily substituted
likely to retain
however,
with the staternent
CONFIRMAIION
errors
Danny
with statistical
Statisti-
in the classroom
and
once they are Iet out on the
Kahneman
quesrions
One was similar to the following
and Amos Tversky
not phrased
(changing
as sta-
the example
fur c1arity): Assume that you live in a town with two hospítals-one
large,
key to success is not always skills, they think that you are telling them that
thc orher smal!. On a given day 60 percent of those born in one of the two
it is never ski lis, always luck.
hospitals
Our inferential
machinery,
that which we use in daily life, is not made
for a complicated
environment
when its wording
is slightly
ronment
in which
modified.
there is no consequential
a statement
Consider
difference
changes
markedly
that in a primitive
between
the starernents
envi-
most
are boys. Which
mude the equivalent
of the mistake
choosing the larger hospital,
i- large
hospital
is it likely to be? Many
(during
a casual
50 percent
conversarion)
when in fact the very basis of statistics
samples are more stable and should f!uctuate
IIVt'rage-here,
statisticians
of
is that
less from the long-term
for each of the sexes-rhan
smaller
sampies.
54
UMBERTO
ECO'S
These statisticians
would have flunkcd their own exams. During
as a quant I counted
staristicians
,,:,
fr
l-
ANTlLlBRARY
hundreds
of such severe inferemial
my days
mistakes
rnade by
~:'
fui components
.
illustration
City, and look at the number
Reebok
Sports
doma in-
of people who, after riding the escalator
specificity
ways: sorne problems
textbooks;
practical
others
problcm.
we can understand
but srruggle when it is presenred
situations:
works
for
breast-fed
as an abstract
lacks a central
"useless"
cornputcr
situa-
doctors examining
patients
detection.
is a misnorner;
kill al! the cancerous
to multiply
technology,
it simply means thar the treatment
cells and that these undetected
out of contro!.)
to examine
malignant
every single one oí the patient's
thern are nonrnalignant,
so the doctor takes a sample by scanning
as possible.
"Why?"
cancer
1 asked.
"Stop
He replied,
"Thc sean is negative."
used in the medical
No Evidence of Disease.
Yer he went
even those who publish
round-trip
Doctors
discussing
is NED, which
stands
rhis matter
for
of No
with plenty of doctors,
papers on their results, is that many slip into the
fallacy during conversation.
milk as something
hy their laboratories-not
rhroughout
doctors
The
in the
has caused plenry of
should
and his school seemed to be advocating
medicine that avoided
',.
deney to look for instances
mechanisrn
con-
not have beliefs, only that
cJoscd beliefs need to be avoided-rhis
Evidence
I
of its ne-
of sugars in the blood and scrapes the
cells. lndecd medicine
many kinds of knowledge
By a mental
generation.
history, owing to this simple kind of inferential
t
','
anything
theorizing.
is what
with their brand
Medicine
of
has gotten
have 110t.
1 call naive empiricism,
that confirrn
we have a natural
ten-
our story and our vision of the
arrogance
primitive,
reaJizing that mothers'
of the 1960s
looked
as if it could be replicated
milk mighr indude
use-
can be easy to find. You take past instances
your theories and you treat thern as euidence. For instance,
show you his "accomplishrnenrs,"
eians will try to convince
pointing
in the midst of the scientific
down at mothers'
thar this
, world+-these instances are always easy to find. Alas, with tools, and fools,
literature
There is no such thing as END, Evidenee
Disease. Yet my experience
1
).
was the reply, "How do
a malnourished
traet of precancerous
better-bur
4;
of cure."
never suspccred
Fiber, ir turns out,
Menodotus
told me after
we have evidence
doctors
evidenee
skeptical-empirical
about
calling himself doctor!
An acronym
I
worrying,
is evidcnce of no cancer"
1 asked. "There
you know?"
around
eheckup,
of ronsils may lead to a higher inci-
1 am not saying here that doctors
the body
that
were also
in rhe risk of breast cáncer,
cancer, but for decades
some kinds of definitive,
state of
certain types
nutrienrs
1960s found it useless beca use they saw no immediate
did not
Then she makes an assurnption
what she did nor see. 1 was once taken aback when a doctor
a routine
(In
cells to see if al! of
with as much precision
of developing
milk some necessary
of
cessity, and so they created
damage
fusiono
cells have
It is not feasible, in the present
risk of a colJection
tissue might actually have a use that escaped their detection.
intestinal
a patient for signs of cancer; tests are typically done on
use bottles).
benefits to rnorhers who breast-feed
acts to slow down the absorption
Take
who want ro know if they are cured or if there is "recurrencc."
fact, recurrence
started
is best visible in cancer
milk
as "it
those who were not
sarne with the dierary fiber found in fruits and vegerables:
a logical mistake in realtty but not in
And as I've said, we can commit
we could simply
a higher likelihood
such as a reduction
dence of throat
rions.
the classroom, This asymrnetry
when
Likewise with tonsils: the removal
logical
that starts with logical rules and applies them equally to all possible
including
had to be in mothers'
neglected,
in
modules-
all-purpose
health problerns,
of cancer-there
undersranding=-a
case of Platonicity
as infants turned out to he ar an increased
still elude us. Furthermore,
than in the
solve a problem
menral machinery=-so-called
our brain
both
but not in
in the textbook
People can manage ro effortlessly
We tend to use different
in different
and reactions
in their applications
we are better at capturing
application.
a social situation
l'
I
of our inferences
to breasr-feed
55
of the benefirs of mothers'
Many people paid the price for rhis naive inference:
a couple of floors, head direcrly to the StairMasters.
This domain
of absence of eutdence
did not make sense"
Club in Ncw York
SHMONFIRMATION!
their scientific
with evidence of absence of the benefirs (another
oí the way we can be ludicrously
specific in daily life, go to the luxury
that could have eluded
simple confusion
who forgot that rhey were sratisticians,
For another
CONFIRMATION
out instances
thar corroborate
a diplomat
will
not what he failed to do. Mathemati-
you that their science is useful ro society
where ir pro ved helpful,
waste of time, or, worse, those numerous
by
nor those where ir was a
rnarhernarical
applications
inflicted asevere cosr on society owing to the highly unernpirical
clegant marhernatical
rheories.
that
nature of
··!..,
56
UMBERTO
ECO'S
AN1ILlBRARY
Even in testing a hypothesis, we tend to look for instances where the
hypothesis proved true. Of course we can easily find confirmation; al! we
have to do is look, or have a researcher do it for US, 1 can find confirmation for just about anything, the way a skilled London cabbie can find
traffic to increase the fare, even on a holiday,
Sorne people go further and give me exarnples of events that we have
been able to foresee with some success-indeed there are a few, like landing aman on the moon and the economic growth of the twenty-first century. One can find plenty of "counrerevidence" to the points in this book,
the best being that newspapers are excellent at predicting movie and theater schedules. Look, 1 predicted yesterday that the sun would rise today,
and it did!
NEGATIVE EMPIRICISM
;i
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The good news is that there is a way around this naive empiricism. 1 am
saying that a series of corroborative facts is not necessarily evidence. Seeing white swans does not confirm the nonexistence of black swans. There
is an exception, however: 1know what staternent is wrong, bur not necessarily what starernenr is correcto If 1 see a black swan 1 can certify that all
swans are not white! If 1 see someone kill, then 1can be practically certain
rhat he is a criminal. If I don't see him kill, 1cannot be certain that he is innocent. The sarne applies to cancer detection: the finding ot a single malignant tumor proves that you have cancer, but the absence of such a finding
cannot allow you to say with certainty that you are cancer-free.
We can get closer to the truth by negative instances, not by verification!
Ir is misleading to build a general rule from observed facts. Contrary to
conventional wisdorn, our body of knowledge does not increase from a series of confirmatory observations, like the turkey's, But there are some
things 1 can rema in skeptical about, and others 1 can safely consider certain. This makes the consequences of observations one-sided. It is not
much more difficult than that,
This asymmetry is immensely practica]. It te lis us that we do not have to
be complete skeptics, just semiskeptics. The subtlety of real life over the
books is that, in your decision making, you need be interested only in one
side of the story: if you seek certainty about whether the patient has cancer, not certainty about whether he is healthy, then you might be satisfied
with negative inference, since it wil! supply you the certainty you seek. So
r
CONFII<MATION
':"
we can
1",,, a lo, frorn d",-b" no'
as much as
SHMONFIRMATION!
w, expcct.
57
Sometimes a
lot of data can be meaningless; ar other times one single piece of informarion can be very meaningful. Ir is true rhat a thousand days cannot prove
you right, but one day can prove you to be wrong,
The person who is credited with the promotion of tbis idea of one-sided
semiskepticism is Sir Doktor Professor Karl Raimund Popper, who may be
the only philosopher of science who is actually read and discussed by actors
in the real world (though not as enrhusiastically by professional philosophers). As 1am wriring these lines, a black-and-white picture of him is hanging on the wal! of my srudy, It was a gift 1 got in Munich from the essayist
Jochen Wegner, who, like me, considers Popper to be about al! "we've got"
among modern thinkers=-well, almost. He writes to us, not to other
philosophers. "We" are the empirical decision makers who hold that uncertainty is our discipline, and that understanding how to act under conditions
of incomplete information is the highest and most urgent human pursuit.
Popper generated a large-scale theory around this asyrnmetry, based
on a technique called "falsification" (ro falsify is ro pro ve wrong) meant
to distinguish between science and nonscience, and people immediarely
started splitting hairs about its technicalities, even though it is not the
most interesting, or the rnost original, of Popper's ideas. This idea about
the asyrnrnetry of knowledge is so Iiked by practitioners, because it is obvious to thern; it is the way they run their business, The pbilosopher maudit
Charles Sanders Peirce, who, like an artist, got only posthumous respect, also came up with a version of tbis Black Swan solution wben Popper was wearing diapers-some
people even callecl it the Peirce-Popper
approach. Popper's far more powerful and original idea is the "open " society, one that relies on skepticism as a modus operandi, refusing and resisting definitive truths. He accused Plato of closing our minds, according
to the argumenrs 1 described in rhe Prologue. But Popper's biggest idea
was his insight concerning the fundamental, severe, and incurable unpredictability of the world, and that 1willleave for the chapter on prediction. ,.
Of course, it is nor so easy ro "falsify," i.e., to state that something is
wrong with ful! certainty, Imperfections in your testing method may yield
a mistaken "no," The doctor discovering cancel' cells might have faulty
• Neirher Peirce nor
philosopher Vicror
1878, as if ir were
business-ancients
prises.
Popper was the first to come up wirh this asyrnmerry. The
Brochard mentioned the importance of negarive empiricism in
a matter held by the ernpiricists to be the sound way to do
undersrood
it irnplicitly, Out-of-prinr
books deliver many sur-
':-1
,-
i.;:"!"i~¡·¡j¡¡¡·¡i¡¡- ••••••••••••••••••
58
UMBERTO
ECO'S
ANTILlBRARY
equal in importance.
Popper introduced the mechanism of conjectures and refutations,
which works as follows: you formulate a (bold) conjecture and you start
looking for the observation that would preve you wrong. This is the alternative to our search for confirmatory instances. If you think the task is
easy, you wil! be disappointed-few
humans have a natural ability to do
this. 1confess that 1 am not one of them; it does not eome naturally to me. *
Counting
to ttvee
I
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1
I1
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Cognitive scientists have studied our natural tendency to look only for
corroboration; they caJ\ this vulnerability to the corroboration error the
confirmatían bias. There are some experiments showing that people focus
only on the books read in Umberto Eco's library. You can test a given rule
either directly, by looking at instances where it works, or indirectly, by focusing on where it does not work. As we saw earlier, disconfirming instances are far more powerful in establishing truth. Yet we tend to not be
aware of this property.
The first experiment 1 know of concerning this phenomenon was done
by the psychologist P. C. Wason. He presented subjects with the threenumber sequence 2, 4, 6, and asked them to try to guess the rule generating it. Their method of guessing was to produce other three-number
sequences, to which the experimenter would respond "yes" or "no" depending on whether the new sequences were consistent with the rule.
Once confident with their answers, the subjeets would formulate the
rule. (Note the similarity of this experiment to the diseussion in Chapter 1
of the way history presents irself to us: assuming history is generated according to some logic, we see only the events, never the rules, but need to
guess how it works.) The correet rule was "numbers in ascending order,"
nothing more. Very few subjects discovered it beca use in order to do so
they had to oHer a series in descending order (that the experimenter would
say "no" ro). Wason noticed that the subjects had a rule in mind, but gave
• As 1 said in the Prologue, the likely nor happening
firming the likely is equivalent
to confirming
is also a Black Swan. So discon-
the unlikely.
SHMONFlliMATIONI
59
him exarnples aimed at confirming it instead of trying to supply series that
were inconsistcnr with their hypothesis. Subjects tenaciously kept trying to
confirm the rules that they had made up.
This experiment inspired a collection of similar tests, of which another
example: Subjects were asked which questions tu ask to find out whether
a person was extroverted or not, purportedly for another type of experimento It was established that subjects supplied mostly questions for which
a "yes" answer would support the hypothesis.
But there are exceptions. Among them figure chess grand masters,
who, ir has been shown, actually do focus on where a speculative move
might be weak; rookies, by cornparison, look for confirmatory instances
instead of falsifying ones. But don't play chess to practiee skepticism. Scientists believe that it is the search for their own wcaknesses that makcs
thern good chess players, not the pracrice of chess that turns thern inro
skeptics. Similarly, the speculator George Soros, when making a financial
bet, kecps looking for instances that would prove his initia I theory wrong.
This, perhaps, is true self-confidenee: the ability tu look at the world without the need to find signs that srroke one's ego."
Sadly, the notion of corroboration is rooted in our intellecrual habits
and discourse. Consider this comrnent by rhe writer and critic John Updike: "Wben Julian Jaynes ... speculates that until late in the second millenniurn B.C. rnen had no consciousness but were automatically obeying
the voices of gods, we are astounded but compelled to follow this rernarkable thesis through al! the corroborative evidence." Jaynes's thesis may be
right, but, Mr. Updike, the central problem of knowledge (and the point
of this chapter) is that thcre is no such animal as corroboratiue evidence.
equipment causing optical illusions; or he could be a bell-curve-using
economist disguised as a doctor. An eyewitness to a crime might be drunk.
But it remains the case that you know what is iorong with a lot more confidence than you knaw what is right. AII pieces of information are not
I
CONFIRMATION
.1
Saw Anofher
r:,.
Red Mini!
The following point further illustrates the absurdity of confirmation. If
you believe that witnessing an additional white swan will bring confirmation that there are no blaek swans, then you should also accept the sta te-
{
.0:-
,
,~
,
,j
.~.
ti
• This confirmation
problem pervades our rnodern liíe, since most conflicts have at
their root the following mental bias: when Ara bs and lsraelis watch news reports
rhey see different stories in the sarne succession of events, Likcwise, Democrats and
Republicans look ar different parts of rhe sarne data and never converge to [he
same opinions. Once your mind is inhabired with a cerrain view of the wor1d, you
will tend to only consider instances proving you to be right. Paradoxical1y,
the
more inforrnation you have, rhe more justified you will feel in your views,
~!~~.
60 UMBERTO ECO'S
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ANTILIBRARY
ment, on pure\y logical grounds,
that the sighting
lent to "all nonwhite
objects are not swans."
would infer that the sighting of a nonwhite
object that is not a swan should
do x, was rediscovered
This argument,
known
as Hempe!'s
by my friend the (thinking)
Dupire during one of our intense meditating
intense walk-discussions,
instincts
"Look, Nassim, lookl No Black Swan!"
dominated
by rare-very
thousands
and thousands
biologically
Not Everyfhing
plague us everywhere.
But such smart pockets of inductive
to involve events that we have encountered
matters
in our natural
n company
tend
charlaran,
environmenr,
member
when children
are presented
with the picture
of a group and are asked to guess the properties
members,
they are capable of selecring which attributes
a child a photograph
of someone
overweight,
weighr-challenged.
But she would respond
differently
t
wil! not attack
of known
in-
judgment
miles tall,
It rakes a lot more
security
wild animals,
Black Swans) remains
environment
new enemies,
enough
rather
analysr
is not a
past, hurnans
have multiplied
they
were
and abrupt
rather
weather
quickly, and to
of sources of uncertainty,
ingrained
be-
Iimited
for us to have built an in-
to make inferences
(i.e., focus on a smal! number
will not
is "our ally,"
and quickly.
of Black Swans today
In the primitive
a marker
a country
uso In the distant
far more accurately
the sources
measurability.'
"tunnel"
is
3, it is impossible-
several hundred
a project is hopeless,
nate fear of them. This instinct
oí the tribe are
volving skin color. If you show her people of dark complexion
run into ahuman
changes, These events were repeatable
she will (mos
to generalizations
being Extremistan,
Ir can deliver a Black Swan after
will nor go bust, a brokerage-house
to newly encountered
Show
tell her that he is a member
that all the members
than we (and our insti-
world,
days to accept that a writer is ungifred,
or a neighbor
Furthermore,
yond
1.-
of other unseen
to generalize.
of a tribe, and ask her to describe the rest of the population:
likely) not jump to rhe conclusion
of a single
'.
in-
rule these events out. But the sales of a book or the mag-
could make inferenees
from which we have learned to avoid foolish generalizaríon.
For instance,
rare-events.
crash, a war will nor happen,
does not
skepticism
The modern
post-alphabet,
environment.
of white ones, so we need to withhold
impossibJe-to
than a thousand
we have never seen him die, or that sorneone is innocent of murder beca use
of na'ive generalization
complex
in the
hail from, but these
to the present,
nitude of social events do not follow such srrictures.
beca use
61
speculate
for survival
for longer than we are inclined to. As 1 said in Chaprer
so our intuitions
we have never seen him kil!. The problem
adequate
is a bit more complex
rurions) seem to realize. How?
of those
We are not naíve enough to believe that someone will be immortal
and statistically
r
from our ancestors.
the instincts
not well adapted
Indeed our environment
Bruno
intense to the point of our not noticing the rain. He
pointed to a red Mini and shouted,
are certainly
tcnsely informational,
rayen para-
walks in London-one
things wrong
inherited
Enst African Great Lakes region where we presumably
bent
mathematician
SHMONFIRMATION!
Medlo","'o'
here that we probably
What confirms the latter statea mind with a confirmation
lo
And we may have learned
is equiva-
ment should confirm the former. Therefore,
bring such confirmation.
'oek
of a red Mini Cooper
should confirm that there are no black swans.
Why? Jusr consider that the statement "al\ swans are white"
CONFIRMATlON
or causes
in uso This instinct,
in a
word, is our predicamento
and ask her
to describe their co-tribesmen, she will assume that they toO have dark skin.
So it seems that we are endowed with speciflc and e1aborate inductive instincts showing us the way. Contrary
to the opinion held by rhe great David
that helief arises from custhat we learn generalizations
solely from experience
Hurne, and that of the British empiricist tradirion,
tom, as they assumed
and empirical
observations,
that we come equipped
generalize
learning
with mental machinery
from experiences
in so me domains
ir was shown from studies of infant behavior
(i.e., to selectively
but rernain skeptical
from a me re thousand
from the learning
that causes us to selectively
acquire
in others).
days, bur benefiting,
of our ancestors-which
inductive
learning
By doing so, we are not
thanks
to evolution,
found its wa)' into our biology.
c,~ •
¡
"
\~
...
.~
i
¡
i:'
f,
";t'
Clearly, wearher-related
and geodesic events (such as tornadoes and earthquakes)
have not changed much over the past millennium,
but what have changed are the
socioeconomic
consequences
of such occurrences. Today, an earthquake
or hurricane cornmands more and more severe economic consequences
than it did in the
past beca use of the interlocking
relationships
between economic enrities and the
intensification
of the "network effects" that we wil! discuss in Pan Three. Matters
that used to ha ve mi Id effects now command a high impacto Tokyo's 1923 earthquake caused a drop of about a third in japan's GNP. Extrapolating
from the
tragedy of Kobe in 1994, we can easily infer thar the consequences of another such
earrhquake in Tokyo would be far costlier than that of its predecessor,