The Problem of Surrogate Samples

Carl Sagan, who was a rather wise fellow.......

In science, scientists should only have 100% faith in the samples they have themselves collected.  When you depend on samples collected by others, you immediately have a host of problems to contend with, and your work is devalued.  You have no idea how careful the collector of your sample might have been at the point of collection -- and you have other problems to do with labelling, storage and sample deterioration.

You should be especially careful if you are using your samples to back up ground-breaking or extraordinary claims.  In my own research I have often used surrogate samples -- collected by colleagues, or rocks. shells and sediments in museum or laboratory collections.  But I have been careful not to attach too much significance to these items, and to use them only if they back up or complement the samples collected and authenticated by myself.  So the surrogates increase your "coverage" and add some strength to your database and to your arguments.

Over the last decade Ixer, Bevins, Pearce and other colleagues have built up a research programme based not on new field work but on surrogate bluestone samples -- bits and pieces of rocks and thin section slides found in dusty museum shoe-boxes, cupboards and display cases.  They have written scores of learned papers and popular journal articles which have been heavily promoted in the media and deemed to represent "the truth about the origins of the bluestones".   Quite apart from some of the outrageous claims they have made about the exceptional accuracy of their "spot provenancing" work, they have often failed to point out the lateral and horizontal variations in rock texture and geochemistry, all too often over-simplifying complex real world situations.  The density of their sampling network at Rhosyfelin, Carn Goedog and elsewhere has also been woefully inadequate, given the spectacular nature of their claims.  

This surrogate sample problem is of course the fundamental -- and probably fatal -- flaw in the new Altar Stone paper, in which Ixer, Bevins and Pearce were of course involved as co-authors.

In this blog, on many occasions in the past, I have quoted Hitchens, Sagan and many others on the matter of extraordinary claims being made on the basis of inadequate or flawed evidence. Carl Sagan said: "Extraordinary claims require extraordinary evidence":
https://rationalwiki.org/wiki/Extraordinary_claims_require_extraordinary_evidence

The Sagan standard is a neologism abbreviating the aphorism that "extraordinary claims require extraordinary evidence" (ECREE).  Sagan used the exact phrase on his television program Cosmos.

The Sagan standard, according to Tressoldi (2011), "is at the heart of the scientific method, and a model for critical thinking, rational thought and skepticism everywhere".

ECREE is related to Occam's razor in the sense that according to such a heuristic, simpler explanations are preferred to more complicated ones. Only in situations where extraordinary evidence exists would an extraordinary claim be the simplest explanation.

See these other posts:

https://brian-mountainman.blogspot.com/2017/05/hitchenss-razor-and-century-of.html
https://brian-mountainman.blogspot.com/2017/08/bluestone-transport-how-archaeologists.html
https://brian-mountainman.blogspot.com/2018/08/the-artificial-significance-of-waun-mawn.html

It's interesting that the anonymous third reviewer of the new "Nature" article made a very similar point:

https://static-content.springer.com/esm/art%3A10.1038%2Fs41586-024-07652-1/MediaObjects/41586_2024_7652_MOESM3_ESM.pdf

He (she?) said:  

The authors propose that the Altar Stone was transported from Scotland to Wiltshire by sea. This would have profound implications for our understanding of Neolithic British society. Extraordinary claims require extraordinary evidence. So it is only right that we inspect the author’s interpretation with a sceptical eye.  Suppose that the authors were correct, and that neolithic Britons had the technology to move a six-tonne block of sandstone from the Scottish highlands to southern England. Then this would beg the question why these people would go through so much trouble for such an ordinary type of rock Why would they travel all the way to Scotland to obtain a plain looking block of Old Red Sandstone, when very similar looking rocks can be found just around the corner in Wales?  Why not go for a more exotic rock type, such as a vesicular basalt?  Marine transport of Old Red Sandstone from Scotland raises more questions than answers..................

I don't think that the authors have dealt with this point adequately in the final (published) version of the paper.   They needed extraordinarily SOUND evidence to back up their extraordinary claim.  So why, oh why, did they not go to EH and say: "We have done some very sophisticated research which suggests that the Altar Stone might have come from Orkney or Caithness.  But the work is based on surrogate samples, and it needs to be validated.  Will you please allow us to take one or two samples directly from the hidden underside of the stone (stone 80) so that we can subject them to the same analysis and so that we can submit a robust and well researched paper for publication and possibly global acclaim?"

Why, oh why, did they not do that?  And if they did do that, why do they not say so?