https://www.rogersandall.com/science-and-consensus/ 2005
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Excerpt
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What happens when the consensus is wrong? Put most simply, work
continues until the mistake is corrected. In any case, as Steven Weinberg says
of physics in Facing Up: Science and its Cultural Adversaries (2001),
even when there are shaky elements in the generally-agreed-upon picture of
things, the consensus in the last hundred years
“has never been simply wrong.” No consensus in the physics community “has ever
been simply a mistake, in the way that in earlier centuries you might say, for
example, that the theory of caloric or phlogiston was a mistake.” The consensus
provides a good initial approximation; it is then adjusted to include necessary
corrections researchers had not properly understood before.
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http://www.ivorcatt.co.uk/x918spargo.htm
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Poetry
Two heads good, three heads better
Roger Sandall
One man’s experience is nothing if it stands alone.
C. S. Peirce
Steven Weinberg’s article discussing Einstein’s mistakes in last
month’s Physics Todaywas
characteristically measured and respectful. But to anyone interested in the
zig-zag progress of science—its diligent and unceasing course corrections—a
more dramatic and revealing article about Einstein had already appeared in the
same journal last September.
This was Daniel Kennefick’s account of
Einstein’s first experience of anonymous peer review. It was an ordeal he had
never been exposed to in Europe, and when he encountered it in America the
great man didn’t like it one bit.
The unprecedented situation arose in 1936 when Einstein sent a paper
to The Physical Review. Kennefick
explains that at that time the Review was rapidly becoming
“the world’s premier journal of physics”, and editor
John Tate took an austere view of his responsibilities. Nobody—not even the
most distinguished contributor—could expect to be favored
or indulged.
When a paper on gravitational waves arrived from Einstein, Tate invited
a reviewer to comment; the reviewer’s anonymous comments were damaging; and
Einstein, “in high dudgeon”, refused to publish in The Physical Review ever
again.
The paper and its details are here of little concern. Einstein shared
authorship with another physicist named Nathan Rosen, and together they
suggested that gravitational waves, which by the 1930s most scientists thought
must exist in principle, were an illusion. But Percy Robertson, the reviewer
invited to comment on their paper, was not convinced.
Well, this is a job! (wrote Robertson to the
editor.) If Einstein and Rosen can establish their case, this would constitute
a most important criticism of the general theory of relativity. But I have gone
over the whole thing with a fine-tooth comb (mainly for the good of my soul!),
and can’t for the life of me see that they have established it.
After explaining why this was so, Robertson went on to recommend that
his criticisms be submitted to the authors for their consideration.
Alternatively, he suggested that Tate might go ahead and publish it as it
stood, since the spin-off and general controversy might be beneficial anyway:
“Such a paper would be certain to give rise to a lot of work in this field of
gravitational waves, which might be a good thing—provided they didn’t flood you
out of house and home.”
In the event the editor decided not to publish, but to send Einstein and
Rosen the anonymous reviewer’s comments. Einstein angrily replied:
Dear Sir,
We (Mr Rosen and I) had sent you our manuscript for publication and had
not authorized you to show it to specialists before it is printed. I see no
reason to address the—in any case erroneous—comments of your anonymous expert.
On the basis of this incident I prefer to publish the paper elsewhere.
This he proceeded to do in 1937 in the Journal of the Franklin
Institute—but not before taking on board the reviewer’s “erroneous” corrections
(having been later persuaded that they were needed), and radically altering
both his argument and its conclusions.
The two heads of Einstein and Rosen may or may not have been better than
one in arriving at their original defective formulation. But three heads were
certainly better than two in establishing where Einstein and Rosen went wrong,
and the whole episode is a good example of the process of intellectual
winnowing, by other minds, through which scientific error is detected and truth
established—little by little, step by step, on the path to eventual consensus.
The new cynicism
Mistakes in science
bring howls of glee from its enemies—some of whom evidently see science as a
mistake in itself. A school of critics dubbed The New Cynics by Susan Haack
believe scientific work to be riddled with error, if not downright absurdity.
Their prophet was the famous Paul Feyerabend. From
his pad in Berkeley he promised to free us from “the tyranny of… such abstract
concepts as ‘truth’, ‘reality’, and ‘objectivity’’ and went so far as to claim
that scientists were little better than practitioners of voodoo.
Others like Bruno Latour argued that science
was mainly about academic egos, rivalry, and power. Now, writes Haack, “New
Cynics like Harry Collins assure us that ‘the natural world has a small or
non-existent role in the construction of scientific knowledge’”, while Kenneth Gergen maintains that the validity of theoretical
propositions in the sciences, “is in no way affected by factual evidence.” (In no way? There has to be something wrong
there.)
In Haack’s Defending Science Within
Reason (2003) this admirable philosopher of science administers a dose
of intellectual sanity and moderation, steering a course between The New Cynics
and The Old Deferentialists (always down on their
knees in awe before scientific achievements). She plainly feels it is time to
move on, and that the stormy 20th-century disputes about verification versus
falsification, or about induction versus deduction—along with the competing
extravagances of academic logicians on the one hand and politically driven
sociologists of science on the other—should be expeditiously relegated to the
archives.
Taking her stand as a “critical common-sensist”
Haack calls for compromise and pragmatism. Like John Dewey she is more fond of the notion of inquiry than of truth, and
although Dewey’s “warranted assertability” does not
make a direct appearance in the argument (or not that I noticed), she gives an
entire chapter to the concept of “warrant” itself. Common-sensism
also maintains that “scientific inquiry is continuous with the most ordinary of
everyday empirical inquiry”, and a range of opinion is
marshalled to support this view.
Back in the 19th century T. H. Huxley had said that science was little
more than trained and organized common sense, while Dewey wrote that
“scientific subject-matter and procedures grow out of the direct problems and
methods of common sense.” The Nobel-winning physicist Percy Bridgman argued
that “there is no scientific method as such… the most vital feature of the
scientist’s procedure has been merely to do his utmost with his mind.” For his
part Einstein himself made a contribution similar to Huxley’s: “the whole of
science is nothing more than a refinement of everyday thinking.”
In his usual distinguished style George Santayana wrote in Reason
in Science: “Science is common knowledge extended and refined. Its validity
is of the same order as that of ordinary perception, memory, and understanding.
Its test is found, like theirs, in actual imitation, which sometimes consists
in perception and sometimes in intent. The flight of science is merely longer
from perception to perception, and its deduction more
accurate from meaning to meaning and from purpose to purpose.”
* * *
All of which stands intriguingly at odds with the views of other
scientists (cited in Science and the Greeks last August) who
prefer to emphasize the discontinuity of science and common sense. In the
opening chapter of his 1992 book The Unnatural Nature of Science (a
chapter with the title “Unnatural Thoughts”) Lewis Wolpert
gave this point of view perhaps its most categorical expression: “Both the
ideas that science generates and the way in which science is carried out are
entirely counter-intuitive and against common sense — by which I mean that
scientific ideas cannot be acquired by simple inspection of phenomena and that
they are very often outside everyday experience. Science does not fit with our
natural expectations.”
…scientific thinking differs from everyday thinking not only in the
concepts used but in what constitutes a satisfactory explanation: common sense
thinking about motion, for example, is not concerned with the spelling-out in
detail of the relationships between terms such as force and velocity — each
involving strictly defined and quite difficult concepts — but can be satisfied
with vague statements.
A further difference is the purpose behind scientific thinking and the
thinking of everyday life. In everyday life one is primarily concerned with
usefulness, whereas science is concerned with a rather abstract understanding.
This is exemplified by Sherlock Holmes when he turns to Watson, who has
been castigating him for not knowing about Copernicus and the solar system, and
says, ‘What the deuce is it to me if you say we go round the sun. If we went
round the moon it would not make a pennyworth of difference to me or my work.’
In fact one of the strongest arguments for the distance between common
sense and science is that the whole of science is totally irrelevant to most
people’s day-to-day lives. One can live very well without knowledge of
Newtonian mechanics, cell theory and DNA, and other sciences…
Doing science (in contrast to doing cooking) requires one to remove
oneself from one’s personal experience and to try to understand phenomena not
directly affecting one’s day-to-day life, one’s personal constructs. In
everyday life one requires no construct as to why bodies fall when dropped or
why children may or may not resemble their parents; it is sufficient that they
do so. Common sense provides no more than some of the raw material required for
scientific thinking.
‘Demarcation’ (a light digression)
Regarding Wolpert’s use of Sherlock Holmes and
Doctor Watson, we might pause and note a curious feature of their altercation.
When Sherlock Holmes says irritably that “If we went round the moon it would
not make a pennyworth of difference to me or my work” it doesn’t take much
imagination to see that as it stands, this statement is clearly false. If the
earth were circling a cold and dead planetary object, and not the sun, it would
make an enormous difference in fact; Holmes would have to lay in firewood till the end of time.
What would not however make the smallest difference to Holmes and his
work is the mere belief that the earth and its inhabitants
revolve around the moon. For the consequences of men and
women having false beliefs are often negligible, whereas the consequences of
different factual conditions in the external world may be immense.
Numerous cultures have held numerous odd beliefs about terrestrial and
planetary motion, but except for awkward mavericks like Copernicus and Galileo
such notions have had no consequence in their lives whatever.
Indeed, people’s heads are full of so much inconsequential nonsense
(inconsequential in the strict sense that there are no practical effects in
daily life whether the ideas are true or false) that one has to work hard to
contrive a test situation in which a serious human penalty must be paid for
false belief. My own preferred crucial experiment involves trains. If Paul Feyerabend, for example, were to
remain sitting on a railway track before an advancing locomotive in the belief
that his friendly voodoo witch-doctor’s spiritual powers could bring the train
to a halt…
Need I say more? Even if we picture a thousand Feyerabendian
witchdoctors joining him sitting on the rails, confident of the outcome, all
zealously chanting together —
If you do voodoo
Like I do voodoo
We’ll stop that train
In its tracks
I find it hard to think the issue would be seriously in doubt. Despite
their most powerful spells, despite their most deeply held beliefs, the whole
bunch would be swept away in one mighty epistemological stroke.
Much weighty stuff has been written about the difficulties of drawing a
clear line between science and superstition, most of it written by
philosophers. For the most part, however, scientists themselves have no
difficulty telling what is and what isn’t science. In
Alan Cromer’s words in his book Uncommon Sense, “parity violation
is, but extrasensory perception is not. Cosmology is, but channelling is not.
Quantum mechanics is, but chiropractic is not.” Yet for some reason
philosophers of science find this distinction much harder to make.
The Train Test can be seen as a rough and ready contribution to solving
this “demarcation dispute.” Anyone can see that for Professor Feyerabend to save himself he would need to draw a clear
and decisive line between, on the one hand, the unempirical voodoo prophecy he
has publicly endorsed, and a scientific prediction on the other, fortified by
Newtonian mechanics, that dooms him to instant annihilation. How that clear and
decisive line should be defined may safely be left to philosophers. They enjoy
playing with words, grammar, and logical puzzles. Scientists themselves are
less interested in such things.
For millions of years variations of the Train Test eliminated cognitive
delusion among living things. The ant that thought ant-lions were friendly
didn’t last long. The calf that mistook an approaching tiger for a cow was
eaten. The herring that believed a shark was just a big herring like itself
ended up inside it. Only with the rise of the vast protective apparatus of
human culture has it been possible for one animal, homo
sapiens, to entertain entirely false ideas about its surroundings and not
be punished.
There is of course a lot of truth in Haack’s view that science and
ordinary inquiry share much in common, and that most day-to-day human thinking
seeks to correct error. But cultures also indulge and accommodate cognitive
nonsense by the ton—especially primitive cultures—and for the most part this
has no observable social effect. If you secretly believe the moon is made of
cheese and inhabited by little green men, no serious price need be paid. No
punishment is ordained for such ideas, nor will holding them shorten your life.
All over the world millions of people believe sillier things and survive.
Consensibility and consensuality
Scientists differ from the generality of mankind in that combating
cognitive nonsense is both their special interest and their skill. One aspect
of this Darwinian culling is anonymous peer review as conducted by scientific
journals—the process that caught Einstein and Rosen in a mistake.
But peer review is just part of an extensive formal and informal social
apparatus to spot mistakes, confirm hypotheses, and verify experimental
results. This apparatus exists to ensure that whatever the subject,
and however difficult the research, the largest possible number of men and
women studying it are able finally to agree. As the distinguished physicist and
science writer John Ziman says in his book Reliable
Knowledge, “the goal of science is a consensus of rational opinion over the
widest possible field.”
What happens when the consensus is wrong? Put most simply, work
continues until the mistake is corrected. In any case, as Steven Weinberg says
of physics in Facing Up: Science and its Cultural Adversaries (2001),
even when there are shaky elements in the generally-agreed-upon picture of
things, the consensus in the last hundred years “has never been simply wrong.”
No consensus in the physics community “has ever been simply a mistake, in the
way that in earlier centuries you might say, for example, that the theory of
caloric or phlogiston was a mistake.” The consensus provides a good initial
approximation; it is then adjusted to include necessary corrections researchers
had not properly understood before.
Postmodern critics who sociologize science as
“social construction” ludicrously exaggerate the role of hegemonic groups whose
sinister influence supposedly controls events. In fact, writes Weinberg, “the exact sciences show a remarkable measure of resilience
and resistance to any kind of hegemonic influence, perhaps more than any other
human enterprise.”
The working philosophy of most scientists is that there is an objective
reality and that, despite many social influences, the dominant influence in the
history of science is the approach to that objective reality…
I think we scientists need make no apologies. It seems to me that our
science is a good model for intellectual activity. We believe in an objective
truth that can be known, and at the same time we are always willing to
reconsider, as we may be forced to, what we have previously accepted. This
would not be a bad ideal for intellectual life of all sorts.
* * *
Error-correction along the path to consensus imposes certain
requirements on scientific communication. It must be what Ziman
calls “consensible”—in other words (and there are
echoes of Popper’s falsifiability criterion here) scientific propositions must
be sufficiently free of obscurity and ambiguity to enable researchers either to
agree with them, or to offer solid objections. Consensibility
denotes a potentiality; consensuality, on the other
hand, is an ideal outcome. “We may say that consensibility
is a necessary condition for any scientific communication, whereas only a small
proportion of the whole body of science is undeniably consensual at a given
moment.”
Like democratic politics, which in some ways it resembles, scientific
research is a social activity. This is essential. As Ziman
wrote in his 1968 book Public Knowledge:
The scientific enterprise is corporate… It is never one individual that goes
through all the steps in the logico-deductive chain;
it is a group of individuals, dividing their labour but continuously and
jealously checking each other’s contributions.
The cliché of scientific prose betrays itself: “Hence we arrive at the
conclusion that…” The audience to which scientific publications are addressed
is not passive; by its cheering or booing, its bouquets and brickbats,
it actively controls the substance of the communications that it receives.
* * *
Zircon crystals are currently under investigation, and in this case
researchers are being gratifyingly showered with bouquets. They have
collectively arrived at the conclusion that the age and composition of the
crystals can mean only one thing: that while the earth may just possibly have
been a fiery hell incompatible with life 4.5 billion years ago, there’s a good
chance that it was already rather cool and watery only 100 million years
later—much earlier than expected.
The report in October’s Scientific American tells how
the research has involved ground-level geology in Western Australia, fossicking
in the Jack Hills 800 miles north of the city of Perth. Tiny barely visible
grains are all there is to work with (though they come from bigger rocks that
are yet to be found), and the process by which these are dated is set out,
along with the Scientific American’s usual superb
illustrations, by principal investigator John W. Valley. Valley’s dating of the
crystals was made possible by earlier work by William Compston
at the Australian National University, whose group invented an instrument
called the Sensitive High-Resolution Ion Micro Probe. A one-time doctoral
student of Valley’s at Colgate University was also involved.
Visits to other researchers at the University of Edinburgh confirmed that
the zircon crystals (because of their high oxygen isotope ratios) must have
formed in an environment of liquid water and low temperatures, with a climate
“more like a sauna than a Hadean fireball.” More and
more men and women are working internationally on zircon-dating and related
matters, in Perth, Canberra, Beijing, Los Angeles, Edinburgh, Stockholm, and in
Nancy, France; tens of thousands of crystals have been fed into ion
microprobes; and as this growing army of investigators arrive at a consensus regarding
the age of these tiny bits of mineral, publishing refereed papers in journals
worldwide—“continuously and jealously checking each other’s contributions”, as Ziman says—the picture of our early world is changing.
Progress in science
Progress in science is difficult, mistakes are made, careers go up and
down and some are ruined. Pioneers like Wegener with his theory of continental
drift may face stiff opposition that takes decades to overcome. Yet the edifice
of science is something far grander and nobler than any New Cynic will ever
understand. It is also of central importance for a humane and reasonable
civilization. Science is one of those areas of human activity where
disagreement does not lead to bomb-throwing or blowing other people up. But since
the late John Ziman (who died in January 2005), a
notable physicist in his day and a Fellow of the Royal Society, has already
expressed these matters more eloquently and with rather more authority than
myself, I shall close by quoting from the chapter “Dissent and Selection” in
his book:
Experienced scientists know that real progress in research is slow and
painful, and that many experimental observations and plausible arguments will
not stand up for long under expert questioning. If science is to evolve, it
must continually purge itself of misconceptions, follies, and practical errors:
there must be preserved a central store of absolutely reliable knowledge, from
which to draw in evaluating novel ideas and on which, very slowly and
carefully, to build. In order that science may retain its reliability and
credibility, each scientist is expected to exercise critical vigilance over his
own work and the claims of his contemporaries…
The facts demonstrate that a healthy scientific community can
accommodate intellectual controversy without breaking down. Consider, for
example, the history of Wegener’s hypothesis of continental drift. Here was an
immense revolution of thought, grossly overdue despite the almost pathological
conservatism that had to be overcome by its advocates. Yet by the standards of
most human institutions, academic as well as overtly political, it was a very
gentlemanly affair, in which the evolution of scientific knowledge was not
disgraced by silenced voices or broken heads.
Although the majority of the leading geologists of the time were
unconvinced by Wegener’s theory, and no doubt cautioned their students against
it, it was not suppressed and forbidden as ‘heresy’. There were several
set-piece public debates and conferences on the subject, and books and papers
supporting Wegener’s interpretation continued to be published. It is likely
that some of the protagonists did not fare quite so well in their academic
careers as hindsight would now consider deserving; but when, eventually, new
evidence from rock magnetism vindicated Wegener’s bold and imaginative
hypothesis, the ‘old gang’ were not swept into scholarly oblivion by the
‘revolutionary’ supporters of the new orthodoxy of plate tectonics.
This truly remarkable and civilized behavior
amongst scientists we take for granted: these are the standards against which
occasional pathologies are judged. And if those who rule society—aristocrats or
democrats, capitalists or socialists, conservatives or radicals—want scientific
knowledge on which they can rely, they must not allow the inner tension of
science to slacken, break, or overbalance.
According to the narrow logic of bureaucratic planning, it is a
wasteful, irrational system that ought to be made efficient and economical. But
by encouraging innovation, yet conserving past achievement, by calling the
gambling competitive spirit from each of us, yet making us also the guardians
of truth and the judges of quality, it is remarkably successful as the source
of many wonders.
John Ziman, Reliable Knowledge
132-133