One of the few reasons to read Xitter: Lee Cronin’s whines

Crank meltdown in progress. Leroy Cronin, who published that ridiculous “assembly theory” article in Nature has been struggling for the last few ways to cope with the ridicule coming his way.

Make a theory at the intersection of evolutionary biology, theoretical physics, complexity theory, & prebiotic chemistry = x 4 the ‘normal’ trolling fun. I love the virtue signalling & the fact they clearly have not even read the paper which is no excuse as it is open access.😂

‘Everyone who disagrees with me is a troll!’ is not the triumphant comeback you think it is. Yes, it’s a theory that combines a lot of disciplines, I agree. But has he considered that maybe the reason he’s getting so much pushback is that people who actually know something about each of those disciplines is saying that the authors don’t understand how the discipline works? I can say that his paper didn’t get evolutionary biology at all right, so now I’m wondering if he also got theoretical physics, complexity theory, and prebiotic chemistry just as wrong.

Gosh first the complexity theorists, then prebiotic chemists followed by the theoretical physicists, & evolutionary biologists. Is that all? Now the creationists are trolling me also. 🤷

I haven’t seen the creationists responding to assembly theory, but now I want to. Not hard enough to actually go digging, unfortunately.

Paradigm shifts involve 1) confusion & anger followed by 2) pronouncements on how obvious it is with the final 3) it has already been done or they thought of it before & it was trivial.

Yikes. The kooks always claim to be leading a ‘paradigm shift’ and start quoting Kuhn.

Here’s another famous quote, this time from Carl Sagan.

“But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown.”

The fact that your ideas are laughed at is not evidence that you are correct.

I love critical feedback because it helps improve stuff & I also get excited when people get ‘triggered’ scientifically as it means something REALLY interesting is shifting. It ain’t pretty but it might accelerate science. #AssemblyTheory

Also, the fact that experts are triggered and reject your theory is not interesting, and doesn’t mean you’ve made a productive change in the world. Creationists trigger me too, that doesn’t validate creationism.

I’m happy to be wrong as I learn more. I like to be almost right occasionally so I can dig deeper. I also want to be bold & honest about it. Science is about taking risks, not beating people up that offend your world view.

No one is offended. No one is beating people up. Cronin is being told that his ideas are wrong, which is what we’re supposed to do.

He’s feeling resentful about being corrected, nothing more. Well, also there should be some shame at publishing such a crappy article in a prestigious journal.

Finally, he reposts something from a supporter:

Absolutely wild to open Twitter and learn that evolutionary biologists think the origin of life is either solved or a non-problem.

No one has said that. The origin of life is not solved and is most definitely a problem of interest. The catch is that assembly theory does not solve any of the problems anyone is wrestling with, and doesn’t seem to solve much of anything.

This is all reminding me of how Dr Wolfe-Simon reacted defensively to criticisms of her claim that life can substitute arsenic for phosphorus. Things got loud back in 2010, and she was insistent that she made a great discovery, but when was the last time you heard about arsenic life? The idea was dead within a year.

Let’s check back in Fall of 2024 and see how Cronin’s theory is holding up.


  1. raven says

    Absolutely wild to open Twitter and learn that evolutionary biologists think the origin of life is either solved or a non-problem.

    Another dead strawperson.

    No one has made that claim.

  2. robro says

    Absolutely wild to open Twitter and learn that evolutionary biologists think the origin of life is either solved or a non-problem.

    Another dead strawperson.
    No one has made that claim.

    Actually, quite a few people have made that claim. God done it. It says so in Genesis.

  3. says

    Sad to see this fellow reduced to trolling on twitter, he seemed to have a much better grasp on origin of life research in his interview with Professor Dave.

  4. wzrd1 says

    “…& the fact they clearly have not even read the paper which is no excuse as it is open access.”

    Yeah, as is my toilet paper and I refuse to read used toilet paper.

    As for arsenic life, I seem to recall reading about a bacteria that uses arsenic for… absolutely nothing, it turns out.

  5. Rob Grigjanis says

    Trying to generalize their theory may well be overreach, but I still think their work on molecular assembly (within Cronin’s wheelhouse) looks solid.

    As I mentioned in the other thread, they claim that

    Among the other complexity measures, MA [molecular assembly index] is unique as it has been shown20 that it can be determined experimentally via tandem mass spectrometry. To date, all other approaches to measure molecular complexity cannot be estimated from experimental measurements, and instead require the formula and connectivity of the molecule to be known.

    If true, that’s pretty powerful.

    Among other things, NASA sent them blind samples which they correctly classified.

  6. says

    Arsenic is complicated.

    If it’s around in excess there are stromatolite communities that incorporate it into the oxidation/reduction part of metabolism. A source of and place to deposit electrons.
    This paper also mentions misanotation of arsenic related genes which lead to undercounts in kinds of chemistry.

    It’s a good paper from a general stromatolite biochemistry perspective.

  7. birgerjohansson says

    I prefer my own “assembler theory”; using nanoassemblers to achieve world domination. Like Daleks, but smaller and without shrill voices. There is absolutely nothing that can go wrong with the plan.

  8. says

    There needs to be a “forced laughter” emoji.

    Is this guy a right-wing extremist? Because bragging about how you’ve “triggered” everyone is what right-wing-extremists have all been doing at least since 2000.

  9. andrewnotwerdna says

    “Assembly theory” also turned up in a recent issue of “American Scientist” – urgh.

  10. says

    @Rob Grigjanis 16
    I’ll take a look. I can believe there are problems with other ways of looking at how molecules get assembled. I don’t actually use those theories or know much about them myself, I just know they exist.
    If my creative project ends up having anything useful it might include suggestions about how molecules were assembled here on earth. It would be something suggestive that other work could look at, but I’m looking at patterns in molecules and protein sub-domains otherwise.

  11. says

    And I still need to work this in, but I still want to think about how our ideas about the relative ages of these things might be affected by it evolving out of simpler versions of both poly-nucleotide and poly-peptides.
    “Structural Phylogenomics Reveals Gradual Evolutionary Replacement of Abiotic Chemistries by Protein Enzymes in Purine Metabolism”
    This goes by subdomain. Spoiler: if our ideas about age aren’t affected phosphate control came first. This makes sense as phosphate release and utilization is intimately involved in a lot of active site chemistry (as opposed to phosphate generating a structural change that drives chemistry elsewhere like in the ribosome).

  12. flex says

    Paging Stephen Wolfram…,
    Paging Stephen Wolfram…,

    Someone is stealing your schtick.

    Paging Roger Penrose…,
    Paging Roger Penrose…,

    Someone is stealing your schtick.

    How many hundreds of times have we seen this?

  13. says

    @Rob Grigjanis
    That article seems fair as someone who runs into papers trying to model biological chemistry. Often tying metabolism to protein domain families and similar.
    I’m working with the molecules, not the math.

  14. nomdeplume says

    It was said of Velikovsky that a Biologist would read it and say well the biology is nonsense but the cosmology sounds interesting. A cosmologist would say well, the cosmology is a load of crap but the history sure sounds intriguing. An historian would say well the history is rubbish but gosh the geology might have something……

    Sound familiar?

  15. chrislawson says


    Thanks for those links. The post by Brenner is great, although perhaps the choice of coal as an abiological example wasn’t ideal (the argument gets much stronger when he gets to kimberlite and diamonds). Particularly enjoyed the line: ‘I did not have time to write something short.’

    That Jirasek paper on MA alien life detection you linked to has a couple of huge red flags. Consider the first two lines of the abstract:

    ‘Detecting alien life is a difficult task because it’s hard to find signs of life that could apply to any life form. However, complex molecules could be a promising indicator of life and evolution.’ True. But notice how by the end of the abstract, he has moved the goalposts: ‘This paves the way to use spectroscopic techniques to unambiguously detect alien life in the solar system, and beyond on exoplanets.’

    ‘Could be promising’ has become ‘unambiguous’.

    From initial impressions (it’s a long paper!) Jirasek does not seem to think there is much difference between analysing the emission spectra of complex chemical atmospheres of distant planets and the absorption spectra of isolated molecules in the laboratory. He talks about successfully identifying individual molecules from tandem mass spectrometry, but does not seem all thate fazed by the fact that they could only identify 3 molecules from a soup of 10 different molecules at high concentration that were chosen to be easy to tell apart. Word search shows zero hits for ‘parsec’, ‘lightyear’, ‘light-year’, ‘light year’, ‘interstellar’, ‘dust’, ‘cloud’, or ‘amino acid’, all terms I would have thought pretty important for discussing the detection of alien life via atmospheric absorption spectra, even if just to briefly mention potential causes of interference. Also, even in his own system, his experimentally observed MA only agrees with his calculated MA with a correlation of 0.86. This correlation is good for some purposes, but in the context of what MA claims it can achieve it’s pretty poor. Imagine how little we’d trust organic chemistry if there was only a 0.86 correlation between the calculated molecular weight and the experimentally observed molecular weight of molecules of known component atoms. The correlation goes down again to 0.75 for calculated MA and experimentally observed IR absorption. And frankly, he gives no reason why MA is a better correlate for complexity than plain old molecular size.

    Worst of all, he conflates measures. This sentence says it all: ‘…we can use experimental measurements on environmental samples to read out the amount of selection and evolution that the samples have been subjected to…’ (p. 17). But this is simply not true. This shows complete ignorance of the Miller-Urey experiments, Strecker synthesis, tholins, and so on. All this is discussed in an excellent and very readable 2010 Brenner paper (, and I would bring particular attention to figure 10, a complex web of organic molecules generated by just two reactions of which Brenner notes ‘A chemist must intervene to prevent this mixture from evolving further to give still more complexity.’ Note that when Brenner says ‘evolving’ he means change in molecules over time, not biological evolutionary processes. Jirasek, like Marshall, assumes all molecular complexity is the result of biological activity despite the reams of evidence of abiological molecular complexity (going back to Strecker in the 1850s, btw).

    Finally, and this is not a criticism but an amusing aside, Jirasek obviously got a lot of his data from pharmaceutical studies. Which is fine. One of his example molecules (see fig 6) is sildenafil, a Viagra competitor. This is possibly a very clever way of driving up research funding on the subject.

  16. Dr. Pablito says

    Late to the party of crapping on assembly theory. Nice to read someone else thought the article in Am Sci was dumb. Not seeing the appeal to this bunkum.

  17. says

    One wonders how many of these dorks who keep proclaiming “paradigm shift” have actually read Kuhn, and then pondered the obvious holes and exceptions in his theory… instead of some Cliff’s Notes summary in a cultural history class they took a couple decades ago. But it wasn’t a history class that dealt with Kuhn’s cherry-picking of data† or suggested flaws in the constantly-shifting rhetoric and definitions in the last two-thirds of the book that limit its applicability, scope, and predictive value. Nor considered that most of the lasting paradigm shifts resulted primarily from more, new, better, and more-replicable data, not revised analyses…

    Unfortunately, “paradigm shift” has devolved to a slogan.

    † He didn’t, or perhaps couldn’t, do enough math to p-hack.

  18. bravus says

    I wonder whether evolutionary biologists didn’t say “The origin of life is either solved or a non-problem”, but rather said it’s not an evolutionary problem? For biological evolution to happen there needs to be biology, and right up to the moment of abiogenesis there isn’t, only chemistry. If this was a demarcation comment, Cronin misunderstood…

  19. jonperry says

    The theory Lee produced actually is useful in life detection projects and in origin of life research. The problem is, his paper made it seem like his theory describes all of biology. The paper over-promised and dramatically under delivered.

    I went to his lecture on the theory today and it seems he now gets why the paper was so hated. He seems to now understand he packaged the thing horribly wrong. We’ll see!

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