TEDGlobal 2009
David Deutsch: A new way to explain explanation
En ny måde at forklare forklaring på
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1,268,796 views
Gennem titusinder af år forstod vore forfædre verden gennem fortællinger og ændringer skete langsomt. Med den videnskabelige tankegang blev vores verdensbillede ændret på kun et par århundreder. Hvorfor? Fysiskeren David Deutsch giver et tankevækkende svar.
David Deutsch - Quantum physicist
David Deutsch's 1997 book "The Fabric of Reality" laid the groundwork for an all-encompassing Theory of Everything, and galvanized interest in the idea of a quantum computer, which could solve problems of hitherto unimaginable complexity. Full bio
David Deutsch's 1997 book "The Fabric of Reality" laid the groundwork for an all-encompassing Theory of Everything, and galvanized interest in the idea of a quantum computer, which could solve problems of hitherto unimaginable complexity. Full bio
Double-click the English transcript below to play the video.
00:18
I'm sure that, throughout the hundred-thousand-odd years
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Jeg er sikker på, at gennem de hundrede tusinder af år
00:23
of our species' existence,
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vores art har eksisteret,
00:26
and even before,
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og endda før det,
00:29
our ancestors looked up at the night sky,
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kiggede vore forfædre op på nattehimlen
00:31
and wondered what stars are.
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og spekulerede på, hvad stjernerne er for noget.
00:34
Wondering, therefore,
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Spekulerede på,
00:36
how to explain what they saw
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hvordan de skulle forklare det, de så
00:40
in terms of things unseen.
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med begreber, der ikke fandtes.
00:45
Okay, so, most people
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Okay, de fleste mennesker
00:49
only wondered that occasionally, like today,
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spekulerede kun over det en gang imellem, ligesom i dag,
00:52
in breaks from whatever
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ind imellem alt det,
00:54
normally preoccupied them.
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som normalt optog dem.
00:56
But what normally preoccupied them
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Men det, der normalt optog dem,
01:00
also involved yearning to know.
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indebar også en længsel efter viden.
01:03
They wished they knew
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De ønskede, at de vidste,
01:06
how to prevent their food supply
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hvordan de skulle undgå, at adgangen til mad
01:08
from sometimes failing,
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en gang imellem forsvandt,
01:10
and how they could rest when they were tired
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og hvordan de kunne slappe af, når de var trætte
01:13
without risking starvation,
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uden at risikere sult,
01:17
be warmer, cooler, safer,
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holde sig varmere, koldere, uden for fare,
01:21
in less pain.
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med færre smerter.
01:23
I bet those prehistoric cave artists
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Jeg vil vædde på, at de forhistoriske hulemalere
01:26
would have loved to know
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ville have elsket at vide,
01:28
how to draw better.
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hvordan man tegner bedre.
01:30
In every aspect of their lives,
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I alle dele af deres liv
01:35
they wished for progress, just as we do.
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ønskede de fremskridt, ligesom vi gør.
01:40
But they failed, almost completely, to make any.
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Men de mislykkedes, næsten totalt, i at gøre nogle.
01:46
They didn't know how to.
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De vidste ikke hvordan, man gjorde.
01:49
Discoveries like fire
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Opdagelser, som ilden,
01:53
happened so rarely, that from an individual's point of view,
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sker så sjældent, at verden, set fra det enkelte menneskes synspunkt,
01:57
the world never improved.
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aldrig blev forbedret.
02:00
Nothing new was learned.
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Man lærte intet nyt.
02:04
The first clue to the origin of starlight
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Den første leddetråd til stjernelysets oprindelse
02:07
happened as recently as 1899: radioactivity.
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skete så sent som 1899: Radioaktivitet.
02:14
Within 40 years,
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Inden for 40 år
02:16
physicists discovered the whole explanation,
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opdagede fysikere hele forklaringen,
02:20
expressed, as usual, in elegant symbols.
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udtrykt, som altid, i elegante symboler.
02:25
But never mind the symbols.
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Men symbolerne er ikke det vigtige.
02:27
Think how many discoveries
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Tænk på, hvor mange opdagelser
02:31
they represent.
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symbolerne repræsenterer.
02:33
Nuclei and nuclear reactions, of course.
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Atomkerner og kernereaktioner, selvfølgelig.
02:36
But isotopes, particles of electricity,
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Men også isotoper, elektriske partikler
02:43
antimatter,
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antistof,
02:47
neutrinos,
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neutrinoer,
02:49
the conversion of mass to energy -- that's E=mc^2 --
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omskrivelsen af masse til energi - altså E=mc^2
02:53
gamma rays,
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gammastråler,
02:55
transmutation.
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transmutation.
02:59
That ancient dream that had always eluded the alchemists
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Den ældgamle drøm, som alkymisterne aldrig fik opfyldt,
03:04
was achieved through these same theories
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blev opnået gennem disse selvsamme teorier,
03:06
that explained starlight
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som forklarede stjernelys
03:08
and other ancient mysteries,
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og andre oldgamle mysterier,
03:11
and new, unexpected phenomena.
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og nye uventede fænomener.
03:14
That all that, discovered in 40 years,
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Det, at alle disse opdagelser gjort på 40 år,
03:18
had not been in the previous hundred thousand,
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ikke var blevet gjort i de foregående hundrede tusinder år
03:21
was not for lack of thinking
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var ikke fordi der ikke blev tænkt
03:25
about stars, and all those other urgent problems they had.
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over stjerner og alle de andre presserende problemer, de havde.
03:29
They even arrived at answers,
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De kom endda frem til forklaringer,
03:32
such as myths,
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såsom myter,
03:34
that dominated their lives,
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som dominerede deres liv,
03:36
yet bore almost no resemblance
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men som næsten ikke havde noget
03:40
to the truth.
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med virkeligheden at gøre.
03:42
The tragedy of that protracted stagnation
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Det tragiske ved denne langtrukne stagnation
03:47
isn't sufficiently recognized, I think.
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er ikke tilstrækkeligt anerkendt, mener jeg.
03:49
These were people with brains of
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De var mennesker med hjerner
03:51
essentially the same design
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af næsten samme udformning
03:54
that eventually did discover all those things.
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som de, der senere opdagede alle disse ting.
03:59
But that ability to make progress
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Men evnen til at gøre fremskridt
04:03
remained almost unused,
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forblev næsten ubrugt
04:06
until the event that
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indtil den hændelse, som
04:09
revolutionized the human condition
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revolutionerede de menneskelige vilkår
04:11
and changed the universe.
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og ændrede universet.
04:13
Or so we should hope.
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Eller, det håber vi.
04:15
Because that event was the
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For den hændelse var
04:17
Scientific Revolution,
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den videnskabelige revolution,
04:19
ever since which our knowledge
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siden hvilken, vores viden
04:21
of the physical world,
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om den fysiske verden
04:23
and of how to adapt it to our wishes,
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og om hvordan vi kan tilpasse den efter vores ønsker,
04:27
has been growing relentlessly.
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har været støt stigende.
04:29
Now, what had changed?
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Men hvori bestod forandringen?
04:32
What were people now doing for the first time
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Hvad var det, folk nu gjorde for første gang
04:34
that made that difference
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og som bevirkede ændringen
04:36
between stagnation
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fra stagnation
04:38
and rapid, open-ended discovery?
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til hastige og ubegrænsede opdagelser?
04:42
How to make that difference
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Hvordan man laver dette skift
04:44
is surely the most important universal truth
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er absolut den vigtigste universale sandhed
04:48
that it is possible to know.
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vi kan kende.
04:50
Worryingly, there is no consensus about what it is.
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Bekymrende nok, er der ikke konsensus om, hvad det er.
04:55
So, I'll tell you.
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Så det vil jeg fortælle jer.
04:57
But I'll have to backtrack a little first.
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Men først må jeg kigge lidt bagud.
05:01
Before the Scientific Revolution,
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Før den videnskabelige revolution
05:04
they believed that everything important, knowable,
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troede man på, at al vigtig viden,
05:07
was already known,
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kendte man allerede,
05:09
enshrined in ancient writings, institutions,
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gemt i gamle skrifter og institutioner
05:12
and in some genuinely useful rules of thumb --
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og i en række praktiske tommelfingerregler,
05:15
which were, however, entrenched as dogmas,
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der dog blev ophøjede til læresætninger
05:19
along with many falsehoods.
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sammen med en hel del falsummer.
05:21
So they believed that knowledge came from authorities
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De mente, at viden kom fra autoriteterne,
05:25
that actually knew very little.
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der dog faktisk vidste meget lidt.
05:28
And therefore progress
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Og derfor var fremskridt
05:31
depended on learning how to reject
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afhængig af en afvisning af
05:34
the authority of learned men,
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de lærdes autoritet -
05:37
priests, traditions and rulers.
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præsterne, traditionerne og magthaverne.
05:41
Which is why the Scientific Revolution
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Det er derfor, den videnskabelige revolution
05:44
had to have a wider context.
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måtte have en bredere sammenhæng:
05:46
The Enlightenment, a revolution in how
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Oplysningstiden - en revolution af den måde
05:50
people sought knowledge,
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folk søger viden
05:53
trying not to rely on authority.
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uden kun at tro på autoriteter.
05:56
"Take no one's word for it."
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"Tro ikke på alt, hvad du hører".
05:58
But that can't be what made the difference.
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Men det kan ikke være det, der gjorde forskellen.
06:02
Authorities had been rejected before, many times.
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Autoriteter er før blevet afvist - mange gange.
06:04
And that rarely, if ever,
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Og det medførte sjældent, om nogensinde,
06:06
caused anything like the Scientific Revolution.
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noget, der kunne minde om den videnskabelige revolution.
06:10
At the time, what they thought
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De mente på den tid,
06:12
distinguished science
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at det, der kendetegnede videnskab,
06:14
was a radical idea about things unseen,
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var en radikal idé om de usete ting,
06:18
known as empiricism.
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kendt som emperisme.
06:21
All knowledge derives from the senses.
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Al viden stammer fra sanserne.
06:26
Well, we've seen that that can't be true.
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Vi ved, at dette ikke kan være rigtigt.
06:29
It did help by promoting
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Det satte dog fart
06:33
observation and experiment.
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i observationer og eksperimenter.
06:35
But, from the outset, it was obvious
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Men fra starten var det tydeligt
06:37
that there was something horribly wrong with it.
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at der var noget helt forkert ved det.
06:40
Knowledge comes from the senses.
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Viden kommer fra sanserne.
06:42
In what language? Certainly not the language of mathematics,
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På hvilket sprog? Sandelig ikke på matematiksprog,
06:45
in which, Galileo rightly said,
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som Galileo så rigtigt sagde,
06:48
the book of nature is written.
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er sproget i naturens bog.
06:51
Look at the world. You don't see equations
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Se på verden. Du ser ikke formler
06:54
carved on to the mountainsides.
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hugget ind i bjergsider.
06:57
If you did, it would be because people
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Hvis du gjorde var det fordi mennesker
06:59
had carved them.
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havde hugget dem ud.
07:01
By the way, why don't we do that?
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Forresten, hvorfor gør vi ikke det?
07:04
What's wrong with us?
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Hvad er der i vejen med os?
07:06
(Laughter)
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(Latter)
07:07
Empiricism is inadequate
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Emperisme er utilstrækkelig
07:09
because, well,
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fordi, tja,
07:11
scientific theories explain the seen in terms of the unseen.
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videnskabelige teorier forklarer det sete med det usete.
07:16
And the unseen, you have to admit,
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Og det usete, må man indrømme,
07:18
doesn't come to us through the senses.
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kommer ikke til os gennem sanserne.
07:20
We don't see those nuclear reactions in stars.
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Vi ser ikke de der kernereaktioner i stjernerne.
07:24
We don't see the origin of species.
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Vi ser ikke arternes oprindelse.
07:27
We don't see the curvature of space-time,
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Vi ser ikke rumtidens kurvatur
07:31
and other universes.
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og andre universer.
07:33
But we know about those things.
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Men vi kender til disse ting.
07:36
How?
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Hvordan?
07:38
Well, the classic empiricist answer is induction.
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Ja, det klassiske empiristiske svar er induktion.
07:43
The unseen resembles the seen.
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Det usete ligner det sete.
07:47
But it doesn't.
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Men det gør det ikke.
07:49
You know what the clinching evidence was
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I ved, hvad det fældende bevis var,
07:51
that space-time is curved?
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på at rumtiden er krum.
07:54
It was a photograph, not of space-time,
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Det var et foto, ikke af rumtiden,
07:57
but of an eclipse, with a dot there rather than there.
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men af en solformørkelse, med en prik her, i stedet for der.
08:01
And the evidence for evolution?
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Og beviset på evolution?
08:03
Some rocks and some finches.
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Nogle klipper og nogle finker.
08:06
And parallel universes? Again: dots there,
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Og parallelle universer? Igen: Prikker der
08:09
rather than there, on a screen.
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i stedet for her, på en skærm.
08:11
What we see, in all these cases,
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Det vi ser, i alle disse tilfælde,
08:14
bears no resemblance to the reality
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har ikke nogen lighed med den virkelighed
08:18
that we conclude is responsible --
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som vi konkluderer ligger bagved -
08:20
only a long chain of theoretical reasoning
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kun en lang række af teoretiske argumentationer
08:24
and interpretation connects them.
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og fortolkninger kan forbinde dem.
08:26
"Ah!" say creationists.
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"Aha!", siger kreationistener
08:29
"So you admit it's all interpretation.
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"Så du indrømmer, at det hele er fortolkninger.
08:31
No one has ever seen evolution.
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Ingen har nogensinde set evolutionen.
08:34
We see rocks.
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Vi ser klipper.
08:36
You have your interpretation. We have ours.
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I har jeres fortolkninger. Vi har vores.
08:39
Yours comes from guesswork,
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Jeres stammer fra gætværk;
08:41
ours from the Bible."
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vores, fra Biblen"
08:43
But what creationist and empiricists both ignore
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Men det som både kreationisten og empirister ignorerer
08:49
is that, in that sense,
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er, at på sin vis
08:51
no one has ever seen a bible either,
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har ingen nogensinde set en bibel heller,
08:54
that the eye only detects light, which we don't perceive.
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for øjnene opfanger blot lys, hvilket vi ikke opfatter.
08:58
Brains only detect nerve impulses.
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Hjerner detekterer blot nerveimpulser.
09:01
And they don't perceive even those as what they really are,
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Og de opfatter ikke engang nerveimpulser, som de i virkeligheden er
09:04
namely electrical crackles.
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nemlig som elektrisk knitren
09:06
So we perceive nothing as what it really is.
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Så vi opfatter ingenting, som det er i virkeligheden.
09:11
Our connection to reality
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Vores forbindelse til virkeligheden
09:14
is never just perception.
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er aldrig kun perception.
09:16
It's always, as Karl Popper put it,
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Det er altid, som Karl Popper formulerede det,
09:20
theory-laden.
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teori-ladet.
09:23
Scientific knowledge isn't derived from anything.
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Videnskabelig indsigt kommer ikke af ingenting
09:26
It's like all knowledge. It's conjectural, guesswork,
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Det er som al viden. Det er antagelser, gætværk
09:31
tested by observation,
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efterprøvede med observationer
09:33
not derived from it.
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ikke udledt af dem.
09:37
So, were testable conjectures
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Så var efterprøvede antagelser
09:40
the great innovation that opened the intellectual prison gates?
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den store innovation, der åbnede de tankemæssige fængselsporte?
09:44
No. Contrary to what's usually said,
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Nej. I modsætning til hvad der normalt siges,
09:47
testability is common,
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så er efterprøvning hyppig
09:49
in myths and all sorts of other irrational modes of thinking.
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i myter og alle andre slags irrationelle tænkemåder.
09:53
Any crank claiming the sun will go out next Tuesday
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Enhver særling, der påstår, at solen slukkes næste tirsdag,
09:57
has got a testable prediction.
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har givet en forudsigelse, der kan efterprøves.
10:00
Consider the ancient Greek myth
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Tænk på den gamle græske myte,
10:03
explaining seasons.
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der forklarer årstiderne.
10:06
Hades, God of the Underworld,
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Hades, underverdenens gud
10:08
kidnaps Persephone, the Goddess of Spring,
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kidnapper Persefone, forårets gudinde
10:11
and negotiates a forced marriage contract,
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og indgår en tvunget ægteskabskontrakt,
10:14
requiring her to return regularly, and lets her go.
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som påbyder hende at vende tilbage med jævne mellemrum, og lader hende gå.
10:18
And each year,
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Og hvert år
10:20
she is magically compelled to return.
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er hun på magisk vis tvunget til at komme tilbage.
10:23
And her mother, Demeter,
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Og hender mor, Demeter,
10:25
Goddess of the Earth,
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agerbrugets gudinde
10:27
is sad, and makes it cold and barren.
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er ked af det, og gør jorden kold og gold.
10:32
That myth is testable.
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Den myte kan efterprøves.
10:35
If winter is caused by Demeter's sadness,
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Hvis vinteren er forårsaget af Demeters sorg
10:39
then it must happen everywhere on Earth simultaneously.
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må den forekomme på samme tid over alt på jorden.
10:43
So if the ancient Greeks had only known that Australia
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Så hvis de gamle grækere blot havde vidst, at Australien
10:46
is at its warmest when Demeter is at her saddest,
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er varmest, når Demeter er mest ked af det
10:50
they'd have known that their theory is false.
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ville de have vidst, at deres teori er forkert.
10:53
So what was wrong with that myth,
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Så hvad er forkert med den myte,
10:56
and with all pre-scientific thinking,
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og med al før-videnskabelig tænkning,
10:59
and what, then, made that momentous difference?
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og hvad var det så, der medførte den betydningsfulde ændring?
11:04
I think there is one thing you have to care about.
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Jeg mener, der er en ting, man må lægge mærke til.
11:08
And that implies
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Og det indbefatter
11:10
testability, the scientific method,
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om det kan afprøves, den videnskabelige metode,
11:13
the Enlightenment, and everything.
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oplysningstiden og alt det der.
11:15
And here is the crucial thing.
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Og her er den altafgørende faktor.
11:17
There is such a thing as a defect in a story.
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Sådan noget, som en fejl i en historie, findes.
11:20
I don't just mean a logical defect. I mean a bad explanation.
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Jeg mener ikke en logisk fejl. Jeg mener en dårlig forklaring.
11:25
What does that mean? Well, explanation
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Hvad betyder det? Ja, forklaring
11:28
is an assertion about what's there, unseen,
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er en påstand om det, der ikke kan ses,
11:31
that accounts for what's seen.
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og som er et udtryk for det, der kan ses.
11:34
Because the explanatory role
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Fordi den forklarende rolle,
11:37
of Persephone's marriage contract
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som Persefones ægteskabskontrakt har,
11:39
could be played equally well
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kunne være spillet lige så godt
11:41
by infinitely many other
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af uendeligt mange andre
11:43
ad hoc entities.
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passende rolleindehavere.
11:45
Why a marriage contract and not any other reason
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Hvorfor en ægteskabskontrakt og ikke en anden årsag
11:48
for regular annual action?
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til sæsonhændelser?
11:52
Here is one. Persephone wasn't released.
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Her er en. Persefone blev ikke ladt fri.
11:55
She escaped, and returns every spring
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Hun undslap, og vender tilbage hvert forår
11:59
to take revenge on Hades,
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for at hævne sig på Hades
12:01
with her Spring powers.
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med sine forårskræfter.
12:03
She cools his domain with Spring air,
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Hun køler hans domæne med forårsluft
12:08
venting heat up to the surface, creating summer.
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leder varme op til jordoverfladen og skaber sommeren.
12:12
That accounts for the same phenomena as the original myth.
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De er et udtryk for det samme fænomen, som den oprindelige myte.
12:16
It's equally testable.
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Den kan lige såvel afprøves.
12:19
Yet what it asserts about reality
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Men, hvad den hævder om virkeligheden
12:22
is, in many ways, the opposite.
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er, på mange måder, det modsatte.
12:24
And that is possible because
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Og det er muligt fordi,
12:26
the details of the original myth
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detaljerne i den oprindelige myte
12:29
are unrelated to seasons,
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ikke har relation til årstiderne,
12:31
except via the myth itself.
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bortset fra via myten selv.
12:35
This easy variability
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At den er så nem at variere,
12:38
is the sign of a bad explanation,
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er et tegn på en dårlig forklaring.
12:42
because, without a functional reason to prefer
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Fordi uden en god grund til at foretrække
12:46
one of countless variants,
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en ud af talrige varianter,
12:51
advocating one of them, in preference to the others,
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så er et forsvar for en af dem, frem for andre,
12:53
is irrational.
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irrationel.
12:55
So, for the essence of what
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Så kernen af, hvad
12:57
makes the difference to enable progress,
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der gør forskellen, så fremskridt muliggøres,
13:00
seek good explanations,
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er at søge gode forklaringer,
13:02
the ones that can't be easily varied,
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dem der ikke let kan varieres,
13:05
while still explaining the phenomena.
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men stadig forklarer fænomenet.
13:10
Now, our current explanation of seasons
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Den nuværende forklaring på årstiderne
13:13
is that the Earth's axis is tilted like that,
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er, at jordens akse hælder,
13:17
so each hemisphere tilts toward the sun for half the year,
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så hver hemisfære hælder mod solen halvdelen af året,
13:20
and away for the other half.
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og væk fra solen den anden halvdel.
13:23
Better put that up.
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Det må jeg hellere vise på skærmen.
13:25
(Laughter)
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(Latter)
13:26
That's a good explanation: hard to vary,
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Det er en god forklaring; svær at variere
13:31
because every detail plays a functional role.
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fordi hver en detalje spiller en funktionel rolle.
13:34
For instance, we know, independently of seasons,
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F.eks. ved vi, uafhængigt af sæsonerne,
13:37
that surfaces tilted away
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at overflader, som hælder væk
13:39
from radiant heat are heated less,
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fra varmestråling opvarmes mindre,
13:42
and that a spinning sphere, in space,
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og at en roterende sfære, i rummet,
13:45
points in a constant direction.
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konstant peger i samme retning.
13:48
And the tilt also explains
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Og hældningen forklarer også
13:51
the sun's angle of elevation at different times of year,
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solens højde over horisonten hen over året,
13:55
and predicts that the seasons
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og forudsiger, at årstiderne
13:57
will be out of phase in the two hemispheres.
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vil være ude af fase på de to hemisfærer.
14:00
If they'd been observed in phase,
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Hvis de havde været observeret som værende i fase
14:02
the theory would have been refuted.
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måtte teorien bortkastes.
14:04
But now, the fact that it's also a good explanation,
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Det faktum, at det også er en god forklaring,
14:09
hard to vary, makes the crucial difference.
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svær at variere, er det, som gør den afgørende forskel.
14:14
If the ancient Greeks had found out
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Hvis de gamle grækere havde vidst noget
14:16
about seasons in Australia,
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om årstider i Australien,
14:19
they could have easily varied their myth
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kunne de nemt have ændret sin myte
14:21
to predict that.
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så den kunne forudsige dette.
14:23
For instance, when Demeter is upset,
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For eksempel at når Demeter er ophidset,
14:25
she banishes heat from her vicinity,
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så bandlyser hun varme fra sin nærhed
14:28
into the other hemisphere, where it makes summer.
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til den anden hemisfære, hvor den giver sommer.
14:31
So, being proved wrong by observation,
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Så selv om deres observationer viste sig forkerte
14:34
and changing their theory accordingly,
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og de ændrede deres forklaring
14:36
still wouldn't have got the ancient Greeks
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så ville de gamle grækere stadig ikke
14:39
one jot closer to understanding seasons,
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være kommet et eneste skridt nærmere en forståelse af årstiderne,
14:42
because their explanation was bad: easy to vary.
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fordi deres forklaring var dårlig: Nem at variere.
14:45
And it's only when an explanation is good
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Og det er kun, når en forklaring er god,
14:48
that it even matters whether it's testable.
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at det overhovedet betyder noget, om den kan afprøves.
14:50
If the axis-tilt theory had been refuted,
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Hvis teorien om den hældende akse var blevet tilbagevist,
14:53
its defenders would have had nowhere to go.
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ville dens tilhængere ikke have haft nogle udveje.
14:55
No easily implemented change
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Ingen nem ændring
14:58
could make that tilt
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kunne få, den hældning til at
15:00
cause the same seasons in both hemispheres.
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forårsage ens årstider på begge hemisfærer.
15:05
The search for hard-to-vary explanations
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Søgen efter forklaringer, som er svære at ændre
15:08
is the origin of all progress.
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er alle fremskridts oprindelse.
15:11
It's the basic regulating principle
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Det er det regulerende grundprincip
15:14
of the Enlightenment.
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for Oplysningstiden.
15:16
So, in science, two false approaches blight progress.
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Så, i videnskab er der to fejlagtige tilgange, som hæmmer fremskridt.
15:20
One is well known: untestable theories.
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Den ene er velkendt: Ikke-testbare terorier.
15:23
But the more important one is explanationless theories.
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Men den vigtigere er forklaringsløse teorier.
15:27
Whenever you're told that some existing statistical trend will continue,
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Når som helst du får fortalt, at en statistisk tendens vil fortsætte,
15:31
but you aren't given a hard-to-vary account
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men du ikke gives en "svært-at-variere" forklaring på,
15:34
of what causes that trend,
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hvad der forårsager den tendens,
15:37
you're being told a wizard did it.
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så får du fortalt, at en troldmand gjorde det.
15:39
When you are told that carrots have human rights
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Når du bliver fortalt, at gulerødder har menneskerettigheder,
15:42
because they share half our genes --
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fordi de deler halvdelen af vores gener,
15:44
but not how gene percentages confer rights -- wizard.
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men ikke hvordan gen-procenter giver rettigheder - troldmanden!
15:50
When someone announces that the nature-nurture debate
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Når nogen proklamerer, at debatten om arv og miljø
15:54
has been settled because there is evidence
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er bilagt, fordi det er bevist,
15:56
that a given percentage of our
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at en given procentdel af vores
15:58
political opinions are genetically inherited,
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politiske holdninger er genetisk nedarvet,
16:02
but they don't explain how genes cause opinions,
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men de forklarer ikke, hvordan gener skaber holdninger,
16:06
they've settled nothing. They are saying that our
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så har de ikke bilagt noget. De siger, at vore
16:08
opinions are caused by wizards,
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holdninger er forårsaget af troldmænd
16:10
and presumably so are their own.
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og det er deres egne formentlig også.
16:13
That the truth consists of
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At sandhed består af
16:16
hard to vary assertions about reality
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"svært-at-variere" påstande om virkeligheden,
16:20
is the most important fact
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er det vigtigste faktum
16:23
about the physical world.
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om den fysiske verden.
16:25
It's a fact that is, itself, unseen,
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Dette er i sig selv et faktum, noget uset,
16:28
yet impossible to vary. Thank you.
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og alligevel umulig at variere. Tak.
16:32
(Applause)
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Applaus
ABOUT THE SPEAKER
David Deutsch - Quantum physicistDavid Deutsch's 1997 book "The Fabric of Reality" laid the groundwork for an all-encompassing Theory of Everything, and galvanized interest in the idea of a quantum computer, which could solve problems of hitherto unimaginable complexity.
Why you should listen
David Deutsch will force you to reconsider your place in the world. This legendary Oxford physicist is the leading proponent of the multiverse (or "many worlds") interpretation of quantum theory -- the idea that our universe is constantly spawning countless numbers of parallel worlds.
In his own words: "Everything in our universe -- including you and me, every atom and every galaxy -- has counterparts in these other universes." If that doesn't alter your consciousness, then the other implications he's derived from his study of subatomic physics -- including the possibility of time travel -- just might.
In The Fabric of Reality, Deutsch tied together quantum mechanics, evolution, a rationalist approach to knowledge, and a theory of computation based on the work of Alan Turing. "Our best theories are not only truer than common sense, they make more sense than common sense,"Deutsch wrote, and he continues to explore the most mind-bending aspects of particle physics.
In 2008, he became a member of the Royal Society of London.
David Deutsch | Speaker | TED.com