More Reasons to Doubt Scientific Pronouncements

It’s unsettling to hear scientists say that long-held beliefs might be wrong, but that’s the nature of science.  Scientific “findings” are tentative, not absolute.  Some see this as a strength of science, but unless actual progress is demonstrated, that strength is called into question.  Recent news casts doubt on various beliefs that had been trusted for a long time.

1.  We were wrong about Neanderthal Man:  For well nigh a century or more, Neanderthals were thought too brutish to make art.  Not any more.  Cave paintings alleged to have been created by Neanderthals have been discovered in Spain, New Scientist reported.  Dating tests are still being done on the figures, which appear to be representations of seals.  The correctives are more serious, though.  The article also pointed out that dating of other cave art is uncertain.  Paul Pettitt from the University of Sheffield let that cat out of the bag: “Even some sites we think we understand very well such as the Grotte Chauvet in France are very problematic in terms of how old they are.”

2.  Rings around the tree dates:  What could be more reliable than tree ring dating?  Trees make annual rings; count them and you’ve got an absolute date.  Why, then, did PhysOrg report, “Tree rings may underestimate climate response to volcanic eruptions”?  A study re-evaluated some estimates, and found them overall quite good, with one “glaring error” – trees might not produce rings after a volcanic eruption strong enough to affect climate.  But if dates could be underestimated by factors not previously considered, could they be overestimated by other unknowns?  The article exposed some of the assumptions that go into the dating method:

The potential absence of rings in the first one to three years following eruption further degrades the temperature reconstruction. Because tree-ring information is averaged across many locations to obtain a representative estimate of northern hemisphere temperature, tree-ring records with and without missing rings for a given year are merged, leading to a smearing and reduced and delayed apparent cooling.

3.  Power Law, or lawless power?   One of science’s great strengths is the ability to describe nature mathematically.  But now, PhysOrg said, it’s time for a “frank discussion,”  about the use of power laws.  These are widely-used techniques to describe relationships between phenomena so as to show causation, instead of just correlation.  Causation is a vexed question in philosophy of science.  There’s nothing like a graph to give the appearance of objectivity.  Not so fast; Michael Stumpf [Imperial College London] and Mason Porter [Oxford], wrote in Science about “the inexact science of trying to apply the power law to situations in science where it’s not always easy to show a direct link between correlation and causation, a key problem they say, in much of the science that is conducted today.”  The original paper in Science began,¹

The ability to summarize observations using explanatory and predictive theories is the greatest strength of modern science. A theoretical framework is perceived as particularly successful if it can explain very disparate facts. The observation that some apparently complex phenomena can exhibit startling similarities to dynamics generated with simple mathematical models has led to empirical searches for fundamental laws by inspecting data for qualitative agreement with the behavior of such models. A striking feature that has attracted considerable attention is the apparent ubiquity of power-law relationships in empirical data. However, although power laws have been reported in areas ranging from finance and molecular biology to geophysics and the Internet, the data are typically insufficient and the mechanistic insights are almost always too limited for the identification of power-law behavior to be scientifically useful …. Indeed, even most statistically “successful” calculations of power laws offer little more than anecdotal value.

Sure enough; Nature last month reported a rethinking about power-law extrapolation in geology.² “Multi-scale modelling of the deformation of magnesium oxide reveals the need for a re-examination of the way in which laboratory data are used to estimate the strength of Earth’s lower mantle,” Andrew M. Walker said.  “….The results suggest that the usual power-law extrapolation is not reliable over the wide range of strain rates that must be considered, potentially changing our view of the way in which the deep mantle deforms.”  Note: “anecdotal value” is indistinguishable from “educated guesswork.”

4.  Rethinking evolution:  Since the discovery of DNA’s structure and function as the carrier of genetic information in the 1950s, most evolutionary work has concerned mutations and natural selection on DNA alone.   A major new monkey wrench has come into focus in the last decade: Epigenetics – heritable information and processes that lie beyond DNA (see new book by Woodward and Gills, The Mysterious Epigenome).  One of the few papers to rewrite evolutionary history with epigenetics in mind is a paper in Current Biology,³ “Epigenetics: What News for Evolution?”   The news is that there is little news – yet.  They don’t even know the questions, let alone the answers.  The authors wrote, “Having a formal body of evolutionary theory that incorporates epigenetics, as well as developing a clearer quantification of the connection between epigenetic variation and phenotypes will allow us to more rigorously ask whether or how epigenetics plays an important role in adaptive evolution.”

References:

_{1. Stumpf and Porter, “Mathematics: Critical Truths about Power Laws.”  Science 10 February 2012: Vol. 335 no. 6069 pp. 665-666, doi:10.1126/science.1216142.}

_{2. Andrew M. Walker, “Earth Science: Limits of the power law,” Nature 481, (12 January 2012), pp. 153–154, doi:10.1038/481153a.}

_{3. Ben Hunter, Jesse D. Hollister, Kirsten Bomblies, “Epigenetic Inheritance: What News for Evolution?”  Current Biology, Volume 22, Issue 2, R54-R56, 24 January 2012, doi:10.1016/j.cub.2011.11.054.}

There is no question that scientists provide a wealth of knowledge in the form of data and observations of the natural world.  Whether they understand what they are looking at (particularly in questions of origins), and can explain it with rigor above that of anecdote, are entirely different questions.  Healthy skepticism is a virtue when approaching scientific claims – especially about non-reproducible phenomena, like origins.  Would that the skeptics, who are usually skeptical of creationism and naive about evolutionism, would develop some healthy skepticism about the nature and targets of their own skepticism.