Friday 22 July 2022

Waun Mawn is like a box of chocolates

The latest Waun Mawn paper - citation below - is an excellent example of the self-correcting nature of good science. Researchers have continued to analyse the data and have changed their hypothesis as they report the new results. There is no gotcha about this. As John Maynard Keynes is reputed to have said, but it was probably Paul Samuelson more recently, “When the facts change, I change my mind. What do you do, sir?” 

I do have one quibble with it though.

I think Nick Pearce's statistical analysis doesn't go far enough and downplays the probability of Waun Mawn stones being used at Stonehenge.

The paper presents a full worked examination of the probability of the missing stones, the eight that are thought to have been removed, being of Lladron origin. There being no Lladron stones at Stonehenge this is the equivalent of any Waun Mawn stones being moved to Stonehenge.

This calculation is based on the the choice of stones to be removed being completely random. This a necessary and useful first calculation to make but it doesn't go far enough because we can make the valid prior assumption that before choosing a stone to take the physical and or spiritual characteristics of the stone would have been assessed.

On Christmas Day afternoon when the the Quality Street tin is passed around you know there were twelve chocolates left at lunch time. Now when it is your turn to choose there are just four Orange Cremes left.

Is it a valid to assume that the original twelve were all Orange Cremes?

No. You can reasonably assume that the Purple ones and the Green triangles would have been preferentially chosen before the Orange Cremes. The twelve could have been any mix that included four Orange Cremes.

I think the same applies to the Waun Mawn stones. The probability that some were removed to Stonehenge is not properly described by the calculation in the paper. What the true probability is and whether they actually were is another matter.

Incidentally the same applies to the stones removed at Stonehenge, why were some removed completely and other left alone? It is unlikely to be a completely random choice. 

Contents of our Quality Street tin Xmas 2021


Richard E. Bevins, Nick J.G. Pearce, Mike Parker Pearson, Rob A. Ixer,

Identification of the source of dolerites used at the Waun Mawn stone circle in the Mynydd Preseli, west Wales and implications for the proposed link with Stonehenge,
Journal of Archaeological Science: Reports,
Volume 45,
ISSN 2352-409X,

1 comment:

  1. I’d have taken the orange creams first! But your scenario is dependant on it being a selection box in the first place. There are too many variables to be certain. Two things need to happen. They need to find out for sure whether ther were more stones at Waun Maun to start with, and they need to suvey for other circles, because the 200+ yr gap between the quarries (if correct) and the Aubrey Holes does require an intermediate use of the bluestones.


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