I get email…from Stuart Pivar!

He rankles easily, and my criticisms of his imaginary gastrulation paper demanded a reply…so Pivar rather haughtily wrote to me and is putting together an addendum to his paper. I pointed out that none of his fancy drawings corresponded at all to any gastrulating embryo, and that there is an utter lack of evidence for any of his hypothetical stages.

His answer? He meant to do that.

You see, he’s illustrating lost stages of embryonic development, stages that were modified by evolutionary changes like condensation (the compression of developmental events), and so modern animals don’t look like that.

We well know the difference between observed embryology and the proposed ancestral model now absent due to the phenomenon of condensation (see Gould, Ontogeny and Phylogeny, 1977)) . The attached paper accounts for the difference.

To publish illustrations without text is like watching the opera with no sound.

Well, sure, but when the opera music is screeching cacophony, and the libretto is a word salad, but the scenery and costumes are spectacularly silly and flamboyant, you’re doing the show a favor by turning off the loudspeakers.

OK, but I’ll just show you some of the words from his submitted addendum — I don’t need to show you the pictures, since they’re just the same imaginative squiggles we saw in the first. He still doesn’t answer what should be the central question of any science paper: how do you know your explanation is valid? Where is the evidence, the data, behind your results? It’s fine to say you’re describing stages or organisms lost to evolutionary history, but then you have to explain how you figured out the missing pieces of the puzzle. He doesn’t.

Actually, all his addendum does is reveal some weird preconceptions that Pivar has, like this:

A previously published paper (Pivar, et al., 2016) attributes the origin of vertebrate form to a hypothetical, lost initial stage of development consisting of the geometrically regular arrays of cells in the blastula resulting from the binary subdivision of the egg through the three axes of space in a coherent sequence of mechanically caused configurations. The sequence is interrupted by the bursting of the hypertense blastula along its ventral midline, followed by the elastic recoil of the surface toward the dorsal midline. This paper examines this event, demonstrating that the embryo is a resulting temporary form, consisting of the compressed form of the blastula—the limbs, ribs, and spine compressed into small bales, the limb buds and somites. Fetal development consists of the gradual resumption of the forms prior to recoil-compression.

Think about that. He’s trying to describe a universal property of vertebrate embryos, which means he has to be discussing a Pre-Cambrian state. But he’s listing derived characters — limbs, ribs, spine — that would not have been present in that “lost” ancestor, and he’s claiming that those characters were actually there, in a compressed form, ready to burst out in developing forms.

We have a word for this. He’s describing preformation. It’s not valid. That’s not how development or evolution work.

He’s also describing forces — “hypertense”, “elastic recoil”, “recoil-compression” — that he does not measure in any way but simply assumes are present. Again, how do you know that? He doesn’t say.

The concordance of this proposed hypothetical blueprint for the development of the vertebrate body with observed embryology is based on the principle of condensation, where over eons of evolutionary time terminal stages are added to embryology while initial stages condense and eventually disappear. Here the sequences, called embryogenesis, are observed embryology, while morphogenesis constitutes a hypothetical reconstruction of initial stages lost to evolutionary condensation.

The stages disappeared! So how do you know what they were? “Hypothetical reconstruction” is not sufficient explanation, especially when those reconstructions lack any “concordance” with the embryology of modern forms. You don’t simply get to do it because you think it looks right.

For example, I never met my paternal grandfather. I never even saw any photos of him — he died when my father was a little boy. I have seen photos and other records of more distant relatives, thanks to genealogy-obsessed aunts. So my grandfather is a “lost” ancestor.


By Pivar-logic, though, I get to ignore all known states and ‘hypothetically’ reconstruct Grandpa in whatever way looks good to me.


I suspect this is probably incorrect, especially since I can’t justify it with evidence in any way.

Oh, except if you use “inductive-deductive reasoning” to claim that it is plausible!

The presentation of the theory engages the Cartesian method of inductive-deductive reasoning to discover a mechanically plausible hypothetical path of cell division that accurately predicts the forms of the organism. The result is a coherent roadmap that directs evolution and guides the generation of the complex body from a single cell.

No, it is not coherent, nor does it accurately predict anything! Show your work, Pivar. It is not enough to say that you can distort your colored blobs into new shapes; you have to show how you know they did that, and relate them to modern forms…which you can’t do, because you lack any understanding of modern developmental biology.

Note how he closes the paper.

This presentation is in the form of a non-rigorous schematic, mechanically, geometrically-based sketch. The authors invite the multitudes of parties interested in the subject to participate in the corroboration (or refutation) of the premise by further investigation by theoretical, computational, and laboratory research.

Remarkable. His work is not rigorous, is based on playing geometry games with sketches, and he admits it. And then he asks other people to justify his premises for him with real research, which he hasn’t done.

I’ll pass.

I do notice, though, that he forgot “silence critics with lawsuits” as one of his strategies for testing his premises.


  1. Siobhan says

    Oh, except if you use “inductive-deductive reasoning” to claim that it is plausible!


  2. johnson catman says

    I do notice, though, that he forgot “silence critics with lawsuits” as one of his strategies for testing his premises.

    Well, that method has served The Orange One well.

  3. monad says

    Be fair. Pivar explicitly stated forms like Pikaia and tunicates were of only questionable connection to the vertebrates, not that he offered any alternative relationships or explained the evidence linking them. But it means he’s not trying to describe some Precambrian animal without limbs or ribs. He’s describing an early Ordovician animal without limbs or ribs.

  4. marcoli says

    A shape will always look like some other shapes. Why? Sometimes the mechanisms of their pattern formation are similar. But more often their similarities are a coincidence because there are really surprisingly few unique kinds of shapes. The striped patterns of a zebra hide is not made the same way as the striped patterns of sand ripples, and the striped patterns of a clouds formed under high wind shear. These things are true even though they turn out very similar in the end. But humans see patterns, and we are easily deluded. Some more easily than others.

    When I was a student I came across a rather disheveled man on campus, handing out little hand-printed pamphlets to students. He thrust one into my hands, and later I looked at it and saw a number of badly rendered photographs of clouds that sort of had shapes. Some were satellite pictures. In the pamphlet he describes how he sees these cloud shapes that are clearly of demons and angels and holy symbols, and he was utterly convinced that these were meaningful messages being sent to us from god. He also mentioned that he had been trying to get scientists from NASA to pay attention, and he was being ignored! So here he was, trying to get someone to care. But no one cared, poor fellow.
    Very passionate, and very very deluded, like our ‘friend’ here.

  5. Nerd of Redhead, Dances OM Trolls says

    And then he asks other people to justify his premises for him with real research, which he hasn’t done.

    Stuart Pivar, your crankdom is showing. Do your own research.

  6. slithey tove (twas brillig (stevem)) says

    after reading about neotony in Gould, I too could have started drawing such doodles, morphing one animal into another, and speculating about embryonic development similarities between disconnected species.
    I want to wiggle out of tht mode by recognizing it as just imagination with no basis for publication and making a fool of meself. Looks like PIvar didn’t restrain himself at that final step so,… I guess I was right. this sure makes him look like a fool. a form of Dunning-Kruger, I guess.

  7. =8)-DX says

    I think I mad some similarly biologically naïve doodles back at primary school. Oh wait I still occasionally do.

  8. EigenSprocketUK says

    PZ: for fun you could assign his inevitable reply to your undergraduate students in return for some extra credit. You could show their best rebuttals anonymously. You’d be able to show that any decent student can see through him, and at the same time write up a well-formed rebuttal.
    Something tells me that this sort of skill will be important to future scientists and science-field communicators.

  9. Golgafrinchan Captain says

    I wouldn’t be so quick to discount your hypothesized grandpa, PZ. It would explain a lot.

  10. themadtapper says

    I’m just posting here to praise PZ’s use of a sprite from Lufia II: Rise of the Sinistrals as his hypothetical grandfather.