Foot scientists, not 3.4myo foot, shocking

They’ve found bones from a 3.4 million year old foot[1] from Burtele, Afar, Ethiopia, with a big toe shaped and oriented more like a human thumb – a bit like the chimp or gorilla foot design. But we know from fossils and footprints that more human-type feet were around by then.

Wow, say palaeoanthropologists Bruce Latimer, Beverly Saylor and Yohannes Haile-Selassie. “The discovery was quite shocking”.

Evidence is shocking when it doesn’t fit any of your beliefs, or more precisely, doesn’t even fit any of the possible candidate theories you are entertaining.

They were shocked because the only theory set they were entertaining was this:

a: By 3.4 million years ago the human lineage had fairly modern big toes;
b: Gorilla and chimp fossils have not been found for that time period;
c: All ape-men fossils from the time were on or very close to the human lineage.

The family tree in their mind looks like this:

Why were they only entertaining these possible theories in their minds?

Because they don’t understand the nature of theorisation: that some theories depend on others; that everything is very fluid; and that a tiny change can flip values all over the belief structure. Take the “absence” of chimp and gorilla fossils for example. Believing they’re absent relies on believing certain fossils are not from them but, as usual, from the more glamorous human lineage. But once we assign some of those fossils to the chimp or gorilla lineages, the “no fossils found” theory doesn’t apply any more!

At this point, sensible readers will start to think, if they haven’t already, that the new foot might be the first ancient chimp or gorilla fossil yet found. Why Bruce, Beverly and Yohannes don’t think that, I don’t know. It shows how hopeless palaeontologist thinkers are that they don’t even deal with their own theories properly. The dogma says no chimp or gorilla fossils, so it’s a ‘fact’.

But even in a few years when that possibility occurs to them, they’ll still be mainly wrong. By not using “theory-based thinking”, i.e. entertaining all candidate theories that explain current observations, they’ve deprived themselves of a genuinely powerful tool that even Victorian crime writers understood:

Maintain a list of the possibilities, eliminating each in turn, and what you have left at the end must be…

…well, if not the ‘truth’, then certainly the most justifiable theory we have.

Palaeontologists tend not to entertain candidate theories because they don’t want to consider any theory that “doesn’t have any evidence for it”. (Despite being able to account for ALL current evidence, there may not be a “Smoking Gun” showing that all OTHER theories are DISproved. But this would be no fault of a candidate theory.) But we know they’ve been doing something wrong because we know they’ve already wrongly eliminated a potentially valid theory… because the new foot evidence doesn’t fit anything already in their minds! THEY MUST HAVE WRONGLY ELIMINATED A POTENTIAL CANDIDATE THEORY! And if they’ve wrongly eliminated one, then how many others have they eliminated?!

Premature elimination occurs in people who see evidence as mainly positive, and whose main mechanism in theorisation is the establishment of ‘truth’. Such people have an erroneous fear of having their candidate theories disproven (a perfectly basic cognitive process actually) because they think people would see them as believers in… just any old thing. Paradoxically, it’s precisely the scientists who do end up believing in any old thing who were unwilling to consider all potential candidate theories honestly in the first place.

Another reason people don’t like to sketch out all possible candidate theories, is they imagine there are infinitely many. But scientists can’t be afraid of infinity; you can easily assign theories to categories and handle infinity that way, and if the worse comes to the worse, any you haven’t covered explicitly can be categorised as “the rest”.

So… this new foot fossil that they can’t explain, can be explained first of all, using their own beliefs. But it can be explained better by exploiting ‘potential candidate theorisation’ more fully. What’s wrong with this tree? Weren’t there enough years to check through possible trees before finding this one?:
Verhaegen’s been saying that sort of thing for years, in case other palaeoanthropologists hadn’t thought of it for themselves. In fact, I’d been wondering for years why we haven’t yet found any side-projecting big toes between the two blue lines (…in raw time at least; that particular lineage between the blue lines might well not include such feet even as offshoots). I wasn’t sure if we’d found any Paranthropus feet, and I suspect we hadn’t before this, if this was one; such feet might help distinguish early upright lineages of chimp from gorilla. Of course, such a foot needn’t be from an actual gorilla ancestor, it might have been from any other late surviving offshoot from the lineage to Ardi.

[1] Yohannes Haile-Selassie, Beverly Z. Saylor, Alan Deino, Naomi E. Levin, Mulugeta Alene, Bruce M. Latimer. A new hominin foot from Ethiopia shows multiple Pliocene bipedal adaptationsNature, 2012; 483 (7391): 565 DOI:10.1038/nature10922

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