It's finally official. Today the online
version of the journal Nature (an authoritative source for
scientists) has an article headlined “Gravitational Waves Discovery
Now Officially Dead.”
In March 2014 the BICEP2 study was
released, and it claimed to have found evidence for gravitational
waves from the beginning of time. It was a result that would have
confirmed the theory of cosmic inflation, a theory about what went on
during the universe's first second. In March of that year,
cosmologists around the world started crowing about how the discovery
of the decade (or even the century) had been made. It was claimed
that “smoking gun” evidence for the cosmic inflation theory had
been found. For months many scientists and “household name” news
sources described the inflated claims of the BICEP2 study as
scientific fact.
But now the roof has caved in on this
claimed breakthrough. Further analysis by the very large team of
Planck scientists has found that the results of the BICEP2 team can
plausibly be explained as being the result of ordinary dust and
something called gravitational lensing, without imagining that the
observations are caused by anything having to do with gravitational
waves, the Big Bang, or cosmic inflation.
From the beginning there were lots of
reason for suspecting that the BICEP2 study was on very shaky ground.
The day after the study was released I released a very skeptical
blog post entitled “BICEP2 Study Has Not Confirmed Cosmic
Inflation,” pointing out some reasons for doubt. I followed this up
in the next month with several other very skeptical blog posts on
BICEP2. The reasons I discussed were out there in April 2014, but
seemed to be ignored by most cosmologists at that time, who got busy
writing lots of scientific papers about the implications of the
supposedly historical BICEP2 study.
Now some cosmologists will point their
fingers at the scientists of the BICEP2 team, and say, “Their
error.” But the blame goes surprisingly wide and deep in this
matter. We must also attach blame to the many other cosmologists who
jumped the gun, and wrote scientific papers based on the BICEP2
claims, treating them as if they were all-but-proven. You can use
this link to find the names of 125 scientific papers that have
“BICEP2” in their titles. A great deal of these papers had titles
such as “The Blah Blah Blah Theory in Light of BICEP2” or “Blah
Blah Blah After BICEP2.” It seems that very many theoretical
physicists took a good deal of time to write up papers
discussing the profound implications of the BICEP2 study, the main
results of which have now been declared “officially dead.”
How can we explain this embarrassing
goof? It couldn't have been because our cosmologists are stupid. After
all, they write these papers with lots of very hard math. Could it
be this snafu occurred because no one warned them that the BICEP2
findings were preliminary, and needed to be confirmed by the Planck
team? No, there were plenty of such warnings, and it was clear from
the beginning the BICEP2 claims were in conflict with some of the
Planck results.
In order to explain this gigantic goof,
one needs to consider sociological factors. The group of scientists
with one particular specialty is a small subculture subject to bandwagon effects, peer pressure, groupthink, group norms, group
taboos, and other sociological influences. Given a proclamation by
enough scientists within a field that a particular result is a
“stunning breakthrough,” acceptance of that result becomes a
group norm. Similarly, once a particular effect or result has been
denounced by enough scientists within a field, then a taboo has been
established, and rejection of that result becomes a group norm. Once
a group norm or group taboo has been established in such a small
subculture, it is rather like a buffalo stampede. Running with the
herd is very easy, and running against the herd is very difficult.
Every subculture imposes punishing sanctions on those within it who
defy the group norms and group taboos.
Peer pressure
For several months, acceptance of the
BICEP2 claims was a group norm within the community of cosmologists,
and so cosmologists fell in line, and followed the herd. A gigantic
bandwagon effect was created. Using many dollars of taxpayers and
universities, they wrote up lots of scientific papers that were based
on the now-defunct group norm.
What lesson can we learn from this
misadventure? One important lesson: make a judgment on the truth of
something based on the facts and the evidence, not based merely on
whether some consensus has been reached by a small subculture of
scientists. That's because such a consensus may be heavily
influenced by sociological factors and economic factors within the
subculture: herd effects, groupthink, group norms, group taboos,
bandwagon effects, and vested interests. Like politicians and judges,
scientists like to imagine themselves as impartial judges of truth,
judging only on the facts. But scientists are subject to sociological
influences just like other people, influences that can decisively
affect their pronouncements.
No comments:
Post a Comment