I'VE ASKED MYSELF
TO WHAT EXTENT AM I
A REALIST ABOUT
SCIENTIFIC THEORIES
OTHER THAN QUANTUM MECHANICS.
FIRST OF ALL, I WOULD BE A
REALIST ABOUT QUANTUM MECHANICS
TOO, IF I KNEW HOW.
I MEAN, CERTAINLY DESCRIBING
SOMETHING THAT'S REALLY THERE,
BUT WHETHER WE CAN
FIGURE OUT WHAT
IT IS OR HAVE TO
IN THE END TO SAY,
HERE, WE'VE DISCOVERED
A FORMALISM WHICH
WORKS BETTER THAN WE KNOW WHY.
I DON'T KNOW, AND I
DON'T THINK WE CAN GUESS.
I DO THINK TWO THINGS.
ONE IS THAT, WITH RESPECT
TO SCIENTIFIC THEORIES
WE REALLY UNDERSTAND, I
AM A REALIST WITH RESPECT
TO THEM IN THE SAME SENSE THAT
I'M A COMMON SENSE REALISM.
SOMETIMES THEY HAVE
ALTERNATIVE FORMULATIONS
WHICH ARE EQUALLY TRUE.
CLASSICAL PHYSICS, WE
KNOW, CAN BE INTERPRETED
AS AN ACTION AT A
DISTANCE THEORY,
BUT IT CAN ALSO BE INTERPRETED
WITHOUT ACTION AT A DISTANCE.
AND THE DUALITY OF
FIELDS AND PARTICLES
WHICH IS FAMOUS IN CONNECTION
WITH QUANTUM MECHANICS
ACTUALLY EXISTED ALREADY IN
CLASSICAL ELECTRODYNAMICS,
A THEORY OF
ELECTROMAGNETIC FIELD.
IN FACT, A LOT OF THE
PHENOMENA OF QUANTUM MECHANICS
ARE ALREADY
ANTICIPATED, OR A LOT
OF THE PROBLEMS IN CONNECTION
WITH QUANTUM MECHANICS
ARE ALREADY ANTICIPATED
IN CONNECTION
WITH THE THEORY OF THE
ELECTROMAGNETIC FIELDS,
INCLUDING THE FACT THAT
YOU HAVE SOME TRADE OFF
AS TO WHETHER YOU CAN DESCRIBE
A PHENOMENON AS DUE TO MAGNETISM
OR DUE TO ELECTRICITY, WHICH
WAS SOMETHING THAT EINSTEIN WAS
IMPRESSED BY AND ONE OF THE
THINGS THAT LED EINSTEIN
TO INVENT A THEORY OF
SPECIAL RELATIVITY,
TO GIVE AN ACCOUNT
OF HOW THAT COULD BE.
I WOULD SAY THAT A LOT OF
PHILOSOPHIES OF SCIENCE, WHAT
I DO THINK IS THAT
IT'S FUTILE TO TRY
TO FIND ONE ACCOUNT
OF SCIENTIFIC METHOD
WHICH FITS ABSOLUTELY
ALL SCIENTIFIC THEORIES.
DIFFERENT SCIENTIFIC THEORIES
HAVE VERY DIFFERENT HISTORIES.
THERE'S VERY
DIFFERENT THINGS THAT
MAKE IT RATIONAL TO ACCEPT THEM.
I'VE HEARD, FOR EXAMPLE,
MOLECULAR BIOLOGISTS
SAY THAT, DEPENDING ON EXACTLY
WHICH CULTURE YOU STUDY,
YOU MAY BE DEALING
WITH PHENOMENA WHICH
ARE HIGHLY REPRODUCABLE
OR PHENOMENA WHICH
ARE ALMOST IMPOSSIBLE
TO REPRODUCE.
AND THAT'S TRUE EVEN
WITHIN ONE AREA.
EVEN WITHIN PHYSICS
ITSELF, THERE
ARE AREAS LIKE WHERE EVERYTHING
IS BOTH EXPERIMENTALLY
CHECKABLE AND THEORETICALLY
HIGHLY DESCRIBABLE,
AND THEN THERE ARE AREAS LIKE
THE THEORY OF TURBULENT FLUIDS,
A THEORY WHICH IS USED BOTH FOR
UNSCENTED AND LITERALLY FLUIDS,
LIKE WATER OR AIR, WHICH
I GUESS IS LITERALLY
FLUID FOR A PHYSICIST,
AND THEN ALSO
FOR THE INTERIOR OF THE SUN
OR THE INTERIOR OF STARS.
AND THERE I'VE HEARD ONE
OF THE GREAT AUTHORITIES
ON THE SUBJECT SAY,
TYPICALLY WE'RE
EXTRAPOLATING FOR PHENOMENA
10 ORDERS OF MAGNITUDE-- THAT
IS, ONE WITH 10
ZEROES AFTER IT--
BIGGER, OR LOUDER, OR STRONGER,
OR WEAKER THAN THE PHENOMENA
WE'RE APPLYING THIS WITH.
WITH RESPECT FOR
EXAMPLE, WHY A GIVEN HORN
WILL PRODUCE THE
PARTICULAR NOISE IT DOES.
THIS IS, IN GENERAL, SOMETHING
THAT YOU CANNOT PREDICT WITH
PAPER AND PENCIL CALCULATION.
SO, THERE ARE
ENORMOUS DIFFERENCES.
WHY DO I MENTION THIS?
WELL, BECAUSE THERE
ARE LITTLE MODELS
THAT WE'D LIKE TO GIVE KIDS,
SAY, IN THEIR FIRST SCIENCE
CLASS, OR THEIR FIRST
PHILOSOPHY OF SCIENCE CLASS,
LIKE, YOU HAVE A THEORY, AND
THE THEORY IMPLIES A PREDICTION.
YOU GO OUT AND LOOK IF
THE PREDICTION IS TRUE,
AND LO AND BEHOLD, IT'S TRUE.
AND THAT'S HOW YOU KNOW
THE THEORY IS RIGHT.
I WAS TALKING TO
PROFESSOR ARONS SAY,
AN ASTROPHYSICIST AT BERKELEY
LAST WEEK WHO SAID, YEAH,
IN MY FIELD IT RARELY HAPPENS.
IT'S ALMOST ALWAYS THAT
YOU STUMBLE OVER SOMETHING,
AND THEN YOU FIGURE OUT
WHAT YOU STUMBLED OVER.
POPPER WANTED TO
SAY, WELL, A THEORY
IS GOOD ONLY IF IT IMPLIES
A FALSIFIABLE PREDICTION.
AND HE SAID, AND THE
GREAT EXAMPLE OF THAT
WAS THE GENERAL
THEORY OF RELATIVITY.
LOOK AT THAT ECLIPSE EXPERIMENT,
WHERE THEY PREDICTED THAT LIGHT
WOULD BE DEFLECTED BY WHEN
IT PASSED CLOSE TO THE SUN,
AND THEY TOOK THESE PICTURES OF
STARS DURING A TOTAL ECLIPSE.
HAD TO BE DOING A TOTAL
ECLIPSE, BUT OTHERWISE YOU
WOULDN'T GET A
PICTURE OF THE STARS.
YOU NEEDED STARS THAT
ARE CLOSE TO THE SUN,
OR ITS APPARENT POSITION
IS CLOSE TO THE SUN.
SO THE LIGHT FROM THEM
PASSES CLOSE TO THE SUN,
BUT YOU HAVE TO BLOCK OUT THE
SUN, SO YOU SEE THE STARS.
SO THEY WAITED FOR
A TOTAL ECLIPSE,
AND THEY TOOK THESE
PHOTOS, AND AS POPPER TOLD
THE STORY, OF ALL OF US
BELIEVED IT FOR A LONG TIME.
EINSTEIN TURNED OUT TO BE RIGHT,
AND HE TOOK THIS BIG RISK,
BECAUSE IF HE HADN'T
BEEN RIGHT, HIS THEORY
WOULD HAVE BEEN FALSIFIED.
AND THEN I THINK JOHN
EARMAN WROTE THIS PAPER,
AND CLARK GLYMOUR
WROTE THIS PAPER
POINTING OUT THAT IT
WASN'T LIKE THAT AT ALL.
THERE WERE, I THINK, FOUR
SETS OF PLATES, AND ONE
SHOWED EINSTEINIAN
DEVIATION, AND ONE
SHOWED NEWTONIAN
DEVIATION, AND ONE
SHOWED DOUBLE
EINSTEINIAN DEVIATION.
AND THERE WERE SOME
BLURRED PLATES, AND SO ON.
AND IN FACT, IT WAS
NOT UNTIL THE '70S
THAT WE HAD GOOD, VERY
PRECISE, DETAILED, WONDERFUL,
EXPERIMENTAL PROOF OF
GENERAL RELATIVITY.
BUT THE THEORY WAS
WIDELY ACCEPTED LONG
BEFORE THAT BECAUSE OF ITS
PLAUSIBILITY, SIMPLICITY,
ELEGANCE.
AND SO ALL THE CONSIDERATIONS
THAT POPPER WOULD HAVE SAID
ARE IRRELEVANT.
EVOLUTIONARY THEORY IS
NOT FALSIFIABLE AT ALL,
WHICH IS WHY POPPER NEVER
CONSIDERED IT A SCIENCE.
BUT IT'S CRAZY NOT TO CONSIDER
EVOLUTIONARY THEORY A SCIENCE.
IT'S MARVELOUS FIT, FIRST
IN THE '30S WITH THE THEN
EVOLVING GENETICS, AND NOW
AGAIN, EVOLUTIONARY THEORIES
BEING TRANSFORMED AGAIN
BY INCORPORATING INTO IT
NEWER KNOWLEDGE OF
GENETIC MECHANISMS.
WHICH IS, AGAIN, RESHAPING
OUR UNDERSTANDING THE DETAILS.
IF YOU DON'T ALLOW THE FEATURES
LIKE INTEGRABILITY, THE ABILITY
TO BE HARMONIZED
AND PUT TOGETHER
WITH THE REST OF THE
SCIENCE THAT'S DEVELOPING,
THEN YOU CAN'T ACCOUNT FOR IT.
I WOULD SAY THAT QUANTUM
MECHANICS BEST FITS,
ACTUALLY, POPPER'S STORY.
WE ACCEPT IT NOT BECAUSE
WE UNDERSTAND IT,
BECAUSE WE DON'T, BUT BECAUSE
IT LEADS TO PREDICTIONS
TO MORE DECIMAL
PLACES THAN WE EVER
IMAGINED A SCIENTIFIC THEORY
COULD LEAD TO TRUE PREDICTIONS,
AND CONTINUES TO SURPRISE US
WITH HOW IMMENSELY ACCURATE
IT IS, EVEN THOUGH THEY
SAY WE UNDERSTAND IT ONLY
IN THE SENSE OF KNOWING HOW TO
MANIPULATE IT MATHEMATICALLY.
THERE'S A WHOLE RANGE OF CASES,
CASES WHERE PREDICTION COUNTS
MOST, CASES WHERE PLAUSIBILITY
AND COHERENCE COUNTS MOST.
CASES WHERE FIT WITH OTHER
SCIENTIFIC THEORIES COUNTS.
AS FAR AS I'M
CONCERNED, THE ATTEMPT
WHEN PHILOSOPHERS OF SCIENCE TRY
TO PRODUCE ONE MODEL AND SAY,
THIS IS THE MODEL FOR HOW YOU
ACCEPT A SCIENTIFIC THEORY,
THEY ALWAYS
EXAGGERATE ENORMOUSLY.
