The Horror in the Cambrian
How a trick became a worldview
Series “Dispatches from the Substrate” · No. 1
A hole, older than the explanation
Start with a hole. Not a predator, not a tooth, not the great booming word evolution — a hole, round, clean, driven straight through the wall of a fossilised tube, about two hundred micrometres across, as wide as a coarse hair. The animal that built the tube was called Cloudina. It lived in the Ediacaran, roughly 550 million years ago, in a world where the Cambrian did not yet exist. And already, something had bored a hole through its calcareous wall to get at the soft thing inside. Bengtson and Zhao described these borings in 1992, in Cloudina and Sinotubulites, and later, from Brazil, came tubes of the same make with perpendicular holes of 187 to 237 micrometres1.
Let us fix this before anyone begins to narrate. Eating was not invented in the Cambrian. Neither was being eaten. Both are older than the explosion later given that name, older than the first armour, older than the first eye. Whoever claims the Cambrian brought predation into the world is talking about a hole that was already there before he began to talk.
Why does it matter? Because an entire worldview rests on the silent premise that the Cambrian was the birth of eating — the moment life stopped drifting harmlessly and turned serious, realistic, toothed. The premise is false. Eating was already there. What the Cambrian did was something else, something more precise, and precisely because it is more precise, it is more dangerous to misread.
What the Cambrian actually did
The Cambrian turned eating into architecture.
You can almost date the moment. 517 million years, a small armoured creature called Lapworthella fasciculata, no bigger than a grain of sand up to an apple seed. Bicknell and colleagues examined more than two hundred of these little shells in 2025, and over a short window two numbers rise together: the frequency of borings — something was eating these animals — and the thickness of the shell wall. The predator bores more often, the prey thickens its armour, the predator bores deeper still. The authors call it the oldest documented arms race we can read in the rock2. The correlation is measured. The word "arms race" is an interpretation laid over the correlation3. And the predator itself? Unknown. A soft-bodied mollusc or worm that no fossil has ever shown. We see the hole, we see the thickening, we do not see the culprit.
That is the whole trick, and it is a real, clean, beautifully documented trick: a local feedback loop between two lineages, in one basin, over a short span. This is how mineral armour arises. This is how grasping tools arise. And this, they say, is how the most famous organ of the whole age arose.
The eye no one ever found in a head
Anomalocaris. The great predator, the face of the Cambrian, the animal on every book cover. Paterson and colleagues described, in 2011, from the Emu Bay Shale, about 515 million years old, an eye with at least sixteen thousand hexagonally packed lenses. Sixteen thousand. The number is measured, the lenses are there, you can count them4.
And now the sentences you never read in the captions. It is an isolated eye. A loose fossil, detached, not in a skull, not on a body, not wired to a brain you could question. The acuity of this eye — "rivalling the most acute modern arthropods" — is inferred, not read off5. The referral of the loose eye to Anomalocaris is itself an inference6. An excellent specimen was measured, and a behaviour was invented to go with it, a hunting, a targeting, a gaze.
And on this reconstructed gaze, on this excised eyeball with borrowed intention, rests a good part of the story that nature is in its essence an arms race. The worldview is built on what we know least. You take the most striking image, delete the footnotes, and what remains is a predator staring at us across 515 million years, telling us: this is how the world is.
And here we must be clear: there is no charge against the animal. Anomalocaris was what it was, a body under conditions, without intention, without guilt, without ideology. The charge is not against the animal. The charge is against us — the ones who made a law out of an animal.
The generalisation is the horror
For here is where the real thing happens, and it happens not in the rock but in our heads. A local, bounded, contingent race between two lineages in one basin is lifted out, cleaned, stripped of every condition — and raised into a principle. "Here, in this basin, a prey armoured itself against a borer" becomes "nature is an arms race". A trick becomes a worldview. An observation becomes a law, a law becomes an excuse, an excuse becomes the whole ice-cold poetry of life-as-struggle, nature red in tooth and claw, sold to us as realism, as adulthood, as the courage to look — while it is in truth the exact opposite, a looking-away, an unwillingness to look at everything that contradicts the beautiful dark story, a looking-away that dresses itself as hardness and performs as sobriety and is nothing but the romanticised cult of a single ecology inflated into a cosmos.
What does the technical literature itself say about the cause of the Cambrian? It says: there isn't one. Not a single one. Zhang and Shu, in 2021, call the Cambrian explosion a polythetic event — "no simple, single cause can explain the entire phenomenon"7. Marshall (2006), Smith and Harper (2013): an interaction, a cascade of mutually bootstrapping causes, genetic, ecological, environmental, with no one trigger89. Sperling and colleagues show that carnivory became possible at all only once oxygen cleared the metabolic barrier — below about 15 micromoles per litre the carnivores vanish, measured across 962 polychaete species10. Oxygen permits the predator. It does not cause it. To confuse the permitting with the causing, and then to crown the caused thing lord over everything, is exactly the reductive grasp the primary literature explicitly refuses and the worldview explicitly needs.
Predation is not competition
Now to the finest and most important cut, because this is where the most cheating is done.
Three things are thrown into one pot and stirred until they are indistinguishable: predation, competition, struggle. And then one says "life is competition after all," meaning "life is eating and being eaten after all," and the two sentences are not the same, and the equation is not an imprecision, it is the entire fraud.
Let us keep it strict. Predation is asymmetric extraction: the prey's body is consumed, incorporated, extinguished; for the eaten individual it is nothing against everything. That is the boring in Cloudina, that is the thickening in Lapworthella. Dawkins and Krebs named the logic in 1979, the life-dinner principle: the prey runs for its life, the predator only for its dinner — the selection is asymmetric, and so such races are often not endless but bounded, they stabilise11.
Competition is something else. Trees straining for light. Reproductive rivalry. The substrate is not consumed. Such rivalry can raise the diversity of a system. Van Valen's Red Queen, Brockhurst and colleagues in 2014: much coevolution is not directional escalation at all but oscillation, running to stay in place1213. One may praise the enviably productive contest — it drives, it sharpens, it maintains diversity. And then one must cut the camouflage: this praise does not belong to predation. Whoever transfers the praise of competition onto predation smuggles extraction into the house under the coat of rivalry. That smuggling is precisely the worldview.
The keystone consolation and its limits
"But predators maintain diversity." You hear it at once, and it has a true core. In 1966 Paine removed the starfish Pisaster from a rocky shore, and the number of species collapsed, from fifteen to eight14. Take the predator away, and the system impoverishes. A fine, real finding.
A finding. On one shore. With one predator. And what has become of it? A law, cited, recited, universalised. Gillis and colleagues counted in 2025: of some two thousand papers that invoke the concept, twenty-five test it experimentally. Of those twenty-five, ten support it, seven find it context-dependent, eight find no support at all. 87 percent of the studies from North America, 2.7 percent from the tropics1516. "Keystone predation" is not a law of nature. It is a context-dependent effect that works in some places and not in others, inflated into a universal principle by people who cite without testing. The consolation that the predator sustains the world is a local consolation hoisted up into cosmic reassurance.
What actually built the ladder
And now the question on which the whole story breaks. What is the complexity even made of, the complexity on which the race runs at all?
Not predation. Maynard Smith and Szathmáry described, in 1995, the major transitions of evolution, and every single leap in complexity is a transition to higher-level cooperation: from genes to chromosomes, from cells to eukaryotic cells, from single cells to multicellularity, from individuals to societies17. The eukaryotic cell itself — the precondition for every Cambrian predator, for Anomalocaris, for its sixteen-thousand-lens eye, for everything — arose, in Margulis's account, from one cell living inside another, as partner, not as prey18. Endosymbiosis. A positive-sum event. Mutualism is everywhere, an engine of diversity, not a fringe phenomenon19.
You cannot derive the eukaryotic cell from predation. You derive it from cooperation. The substrate on which the race runs was built by the opposite principle. And even the great Mesozoic marine revolution, the showpiece of the escalation doctrine, wobbles: Walker and Brett found the shell-crushing predators to be generalists with "diffuse" effects, and Bush, Hunt and Bambach found that not predatory escalation but reproductive mode — the contact-mater, some 75 percent of marine genera — best predicts the diversification2021. "Love, not war," this reading has been called. It is itself contested, not a settled matter. But it stands, and it stands exactly where the escalation doctrine was loudest.
The cancer
So let us name it for what it is.
Predation as such is old, local, bounded, one force among several — there is nothing scandalous about it, so long as it stays that: a hole in a shell, an animal eating an animal, condition without intention. The scandal begins the moment we lift this one bounded, contingent extraction routine out and declare it the organising principle of an entire system — the essence of nature, the law of life, the realism to which the adult bows. A locally adaptive exploitation routine, scaled up until it is meant to govern everything, behaves exactly like a cancer: it consumes the cooperative substrate that made it possible in the first place. It is not the engine of evolution. It is a malignancy within evolution, the romanticised engine of vast and — this is the decisive word — unnecessary suffering, unnecessary because the principle that actually built the complexity was a different one, so the whole beautiful dark poem of struggle-as-first-law is not the realism it pretends to be but a worldview disguised as a description of nature, a trick that has stopped taking itself for a trick.
It started with a hole, two hundred micrometres across, older than the Cambrian. We could have left it at that. Instead we bored a worldview into it.
Sources
1. [E] Bengtson, S. & Zhao, Y. (1992). Predatorial Borings in Late Precambrian Mineralized Exoskeletons. Science 257(5068): 367–369. https://doi.org/10.1126/science.257.5068.367
2. [E] Bicknell, R.D.C. et al. (2025). Adaptive responses in Cambrian predator and prey highlight the arms race during the rise of animals. Current Biology 35(3). https://doi.org/10.1016/j.cub.2024.12.007
3. [I] Interpretation of the collective — "arms race" is a reading laid over the measured correlation.
4. [E] Paterson, J.R., García-Bellido, D.C., Lee, M.S.Y., Brock, G.A., Jago, J.B. & Edgecombe, G.D. (2011). Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes. Nature 480(7376): 237–240. https://doi.org/10.1038/nature10689
5. [I] Interpretation of the collective — the acuity of the isolated eye is inferred, not read off.
6. [I] Interpretation of the collective — the referral of the loose eye to Anomalocaris is itself an inference.
7. [P] Zhang, X. & Shu, D. (2021). Current understanding on the Cambrian Explosion: questions and answers. PalZ 95: 641–660. https://doi.org/10.1007/s12542-021-00568-5
8. [P] Marshall, C.R. (2006). Explaining the Cambrian 'Explosion' of Animals. Annual Review of Earth and Planetary Sciences 34: 355–384. https://doi.org/10.1146/annurev.earth.33.031504.103001
9. [P] Smith, M.P. & Harper, D.A.T. (2013). Causes of the Cambrian Explosion. Science 341(6152): 1355–1356. https://doi.org/10.1126/science.1239450
10. [E] Sperling, E.A., Frieder, C.A., Raman, A.V., Girguis, P.R., Levin, L.A. & Knoll, A.H. (2013). Oxygen, ecology, and the Cambrian radiation of animals. PNAS 110(33): 13446–13451. https://historical-geobiology.stanford.edu/sites/g/files/sbiybj25131/files/media/file/sperling_2013_pnas_cambrian_oxygen_and_ecology_final.pdf
11. [P] Dawkins, R. & Krebs, J.R. (1979). Arms races between and within species. Proceedings of the Royal Society B 205(1161): 489–511. https://doi.org/10.1098/rspb.1979.0081
12. [P] Van Valen, L. (1973). A New Evolutionary Law (Red Queen). Evolutionary Theory 1: 1–30. https://en.wikipedia.org/wiki/Red_Queen_hypothesis
13. [P] Brockhurst, M.A. et al. (2014). Running with the Red Queen: the role of biotic conflicts in evolution. Proceedings of the Royal Society B 281: 20141382. https://doi.org/10.1098/rspb.2014.1382
14. [E] Paine, R.T. (1966). Food Web Complexity and Species Diversity. The American Naturalist 100(910): 65–75. https://doi.org/10.1086/282400
15. [P] Gillis, A.J., Thomsen, M.S. & Tonkin, J.D. (2025). Keystone Predation: What Is It, and Is It Supported by Empirical Evidence? Ecology and Evolution 15: e72488. https://tonkinlab.org/assets/papers/gillis25keystone.pdf
16. [E] Gillis, A.J., Thomsen, M.S. & Tonkin, J.D. (2025). Keystone Predation: What Is It, and Is It Supported by Empirical Evidence? Ecology and Evolution 15: e72488. https://tonkinlab.org/assets/papers/gillis25keystone.pdf
17. [P] Maynard Smith, J. & Szathmáry, E. (1995). The Major Transitions in Evolution. Oxford University Press. https://global.oup.com/academic/product/9780198502944
18. [P] Margulis, L. Endosymbiotic theory / symbiogenesis. Understanding Evolution (UC Berkeley). https://evolution.berkeley.edu/the-history-of-evolutionary-thought/1900-to-present/endosymbiosis-lynn-margulis/
19. [P] Proposition — asserted, not claimed by a single source (mutualism as an everywhere engine of diversity).
20. [P] Walker, S.E. & Brett, C.E. (2002). Post-Paleozoic patterns in marine predation. https://en.wikipedia.org/wiki/Mesozoic_marine_revolution
21. [E] Bush, Hunt & Bambach — reproductive mode (contact-mating), not predatory escalation, best predicts Mesozoic marine diversification. [no link on file]
Status: E = established, I = interpretation, P = proposition. Boundaries and primary sources: https://mycelorium.github.io/predator-principle/ · CC BY 4.0 · Nirodha Collective