Articles to 2017-01-08

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First the link to this week’s complete list as HTML and as PDF.

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Cheon & Hong start from a plausible hypothesis – high ranking primates are known to monopolise high value food sources making it desirable for lower ranking ones to over indulge whenever there’s a chance. Unfortunately their study fails to prove their case and is systematically unsuitable for doing so. The main point to invalidate it is that they, like so many others, completely ignore the homoeostasis at the centre of every living being.[1] A short-term reaction observed in the order of hours tells us less than[2] nothing about long term adjustments leading to observable effect on body mass. Starting from there they seem determined to repeat every statistical mistake in the books. If their hypothesis had any merit, their regression lines in figure 1 would have to stay disjunct and never cross, certainly not cross near the middle. In all their discussion they fail to mention the right side of that diagram once. (And of course we are again only shown errorless regressions, no data.) In their study 2 they tell us noting about what was measured and the mean and SD given are meaningless and unitless numbers. One thing that can be said is, that the difference between means, the effect, is only a third of the internal SD within groups. In figure 4 they show standard errors. The standard deviations would have to be about seven times as large.

I know I’m repeating myself. The standard error is appropriate for a single, well defined, true value, for which a number of independent but inaccurate measurements are being made. The standard deviation describes independent measurements of independent values, that are known or expected to vary in the population of specimens.

And of course all their results are open to an alternative and equally plausible explanation. Here we have a group of student participants in a study, that are induced to feel unfairly disadvantaged. Would that not make them want to avail themselves as much as possible of anything on offer to compensate? This reaction being unconscious and driven by primeval impulses, it’s not surprising that they tend to rate calories over commercial value.

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Since Arrhenius in 1895 there has never been any serious doubt about the warming and insulating effect of carbon dioxide. All the discussion has solely been concerned about magnitude and claims of recent values being unprecedented and outside of natural variation. Tweaking models to diverge right at the edge of the range of observations and using their results as a basis for extrapolation is an obvious and glaring misuse of modeling. Bakker et al. won’t solve the problem of far too many parameters for them to be determined by data, but provide a large step towards understanding the past better. Even from a model that reproduces past data perfectly, extrapolation remains a questionable and unreliable exercise, doing it from one that can’t is an obvious nonsense.

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Camenisch on the other hand is an example of what models are good for and demonstrates their correct use in e.g. trying to elucidate mechanisms. Apart from that, things like something more than colour alone to represent data values and units on diagram scales would have been nice to get. Also blue for dryer and red for wetter seems a strange choice of labeling, but reading the text I’m not quite sure if that scale is not presented the wrong way round.

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The total lack of any allusion to an afterlife or to an immortal soul in pre-exilic Biblical texts is a well known, accepted, but little discussed fact. The denial of a resurrection was still an important Jewish minority belief (Sadducees) up to the Roman imposed second exile. I have long wondered, whether the Koranic condemnation of just that unbelief was not related to the Jewish exiles in Arabia. Crone’s connection of many of the Koran’s main tenets to a Jewish Christian influence makes that idea just that bit more probable.


1
One of the best investigated examples is the basic feeling of happiness, which seems to be a property of innate personality. Even large changes in circumstance in both directions have been shown to affect it only in the short term with regression to the default value in a few years or less.     Zurück
2
Homoeostatic response often overcompensates its driver and results in the equilibrium moving in the opposite direction of the short term reaction.     Zurück

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