60 THE SCIENTIST | the-scientist.com
READING FRAMESS
cience seems under assault. Attacks
come from many directions, ranging
from the political realm to groups and
individuals masquerading as scientific enti-
ties. There is even a real risk that scientific
fact will eventually be reduced to just another
opinion, even when those facts describe natu-
ral phenomena—the very purpose for which
science was developed. Hastening this erosion
are hyperbolic claims of “truth” that science is
often perceived to make and that practicing
researchers may themselves project, whether
intentionally or not.
I’m a researcher, and I get it. It seems
difficult to explain the persistent success of
scientific theories at describing nature, not
to mention the constant march of techno-
logical advancement, without assigning at
least some special epistemic status to those
theories. I explore this challenge in my
book, What Science Is and How It Really
Works. If the history of science teaches us
anything, it is that the ability of a theory to
predict unobserved phenomena and lead
to amazing new technologies is no proof
that said theory is “true.”
For example, in addition to explaining
the dynamics of the known solar system,
Isaac Newton’s mechanics enabled stun-
ningly accurate predictions of other astro-
nomical phenomena, such as Halley’s comet
arriving later than normal in 1759 due to the
gravitational effects of passing close to Jupi-
ter. Even more impressive, in the early 1800s
when astronomers determined that the orbit
of Uranus deviated from Newtonian predic-
tions, they concluded that Newton’s theory
was not wrong; rather, the existence of a
previously unobserved planet was posited
and was later found exactly where it was
expected to be (and named Neptune).
Such successes of the scientific revolu-
tion were so impressive that philosophers
developed whole new theories of knowledge
to try to explain how scientists appeared tohave used observation and reason to discover
fundamental truths. In doing so, both sci-
entists and epistemologists attempted to
dismiss what logicians have known since
antiquity: that no amount of correctly
predicted effects can prove a hypothesized
cause. Attempts to do so commit the fal-
lacy of “affirming the consequent”—in
other words, scientific theories are always
underdetermined by the available data.
But isn’t this just ivory-tower semantics?
Logicians can raise their eyebrows and wag
their fingers, but scientists are busy making
progress in the real world. Don’t the suc-
cesses of Newtonian mechanics prove that
the laws Newton posited must really be true?
Otherwise how could the theory have picked a
single spot in the vast expanse of the cosmos
and found exactly where Neptune was?
Affirming the consequent, affirming the
schmonsequent!
Things do not always work out this w ay,
however. In 1859, astronomers determined
that the orbit of Mercury was not behav-
ing, over time, as Newtonian mechanics
predicted. So another new planet (named
Vulcan) was posited and its probable posi-
tion calculated. Unlike the prediction of
Neptune’s existence, this supposition did
not pan out; rather, Newtonian mechanics
was an incorrect theory in this context. Its
conceptions of time, space, and simultaneity
were simply wrong. A different scientific
theory—Einstein’s theory of relativity—was
required to later explain Mercury’s abnor-
mal perihelion precession.
Examples of such later-overturned hy-
potheses litter scientific history across many
fields: the spontaneous generation of life,
bad air and the imbalance of four essential
humors causing disease, embryos arising
from homunculi, Pasteur’s theory of how
vaccines work, Mesmer’s imponderable fluid
that regulated human health, and so on.
So, what really strains credulity more?To insist that we know that electrons, atoms,
black holes, and dark matter are real because
of how many observations we can explain
and predictions we can make by positing
their existence? Or to simply admit that
science cannot support a claim of absolute
truth regarding the abstract, unobserved
scientific objects and laws that are posited to
govern this world?
One could argue that we live in a time
of sound bites and simplicity that cannot
tolerate nuanced thinking. If scientists
don’t bang the gong of “truth,” then it may
only hasten the dismissal of science as just
another opinion. However, I would argue
that this position does not give the intended
audience enough credit, and that claiming
absolute truth ultimately does more harm
than good, not only for the interface of sci-
ence with the public, but for the practice of
science. If data are sacrosanct to the sciences,
then let us embrace the historical data on
science itself.gJames Zimring is an immunologist at the
University of Virginia School of Medicine.
Read an excerpt of What Science Is and How
It Really Works at the-scientist.com.Cambridge University Press, July 2019Studying the history of science’s successes and failures can give us
much-needed perspective on the pursuit of knowledge.BY JAMES C. ZIMRINGThe Pragmatic Truth of Scientific Claims