"How can the worst-designed systems [in nature] be the most durable?
The answer, rather counterintuitively, is that they are durable because they are not optimised. An optimised design is one that has been tuned precisely as possible to its current conditions. Every component fits perfectly to its present demands. Nothing is wasted, nor is anything redundant. The system performs beautifully under exactly the conditions for which it was optimised.
What happens when the conditions change?
The more precisely a system is tuned to one environment, the greater the chance that it will fail catastrophically when that environment changes. Environments change all the time, so this is not a hypothetical concern. The climate changes, competitors arrive, the pH of the environment changes, a new virus turns up, food sources disappear, your host takes an antibiotic. The one thing you can say for sure about present conditions is that they will not last.
So while the giraffe's laryngeal nerve is insane, the same basic layout works in a fish, a frog, a lizard, a mouse, an elephant, and a whale. It works across every body plan, every neck length, every thoracic arrangement that vertebrates have ever produced. An optimised routing that always took the shortest path for the specific neck length of the specific animal, would need to be re-engineered every time the body plan changed. What looks like a stupid design today is a design that hasn't broken when other things changed.
Which brings me to the giant panda, an animal that is exquisitely adapted to its niche, eating almost exclusively bamboo, employing a modified wrist bone to grip its stems, digesting them with a gut that is still essentially the gut of a carnivore, processing its food so inefficiently that it must eat for 14 hours a day. The panda, an epitome of specialisation, is also, in ecological terms, a dead animal walking. If bamboo were to disappear, thanks to deforestation, climate change, or disease, the panda ends up with nothing. Its optimisation is its obituary.
The contrast is the rat. The brown rat, Rattus norvegicus, not specialised for anything in particular, eats whatever is available, lives wherever it finds itself. It has no remarkable adaptations, no precise fit to any specific niche. It is a generalist that is mediocre at 100 different things, and not brilliant at any. The rat is everywhere and will be here long after the panda is a memory. The rat is good enough.
In 1956, the economist Herbert Simon coined the word 'satisficing,' a portmanteau of 'satisfy' and 'suffice,' to describe how real decision-makers operate. Classical economics assumes that rational agents always optimise. They survey the available options, compute the expected value of each, and select the very best one. Simon pointed out that this is quite insane. No real agent has the time, the information, or the computational power to optimise to that degree. What real agents do is set a threshold that we might call 'good enough,' and pick the first option that makes it over that threshold.
Simon won a Nobel Prize for his observation, and I’m going to suggest that he had to. The idea that 'good enough' is a legitimate strategy, and not a failure to try hard enough, not a compromise, nor is it laziness, but a defensible, mathematically sound approach to operating in a complex world was alien to the intellectual culture of the 20th century. It took a Nobel prize to make this idea respectable. Ironically, biology has been employing this principle for four and a half billion years before Herbert Simon figured out a name for it. I would assert that every organism that has ever lived is a satisficer. Few, if any, have ever optimised, because optimisation requires the kind of global knowledge that no real system, biological, economic, or personal, has ever possessed...
What lasts is not what’s best. What lasts is the thing that is most viable across the widest possible suite of conditions, for the longest period of time. 'The best', and 'the most durable' are not the same, and in fact, I would say they are in tension with one another. The more finely you tune a system to current conditions, the more fragile you make it. The more you aim for the optimal, the more dependent you become on the world being unchanged. And it never will.
Good enough is not a consolation prize, nor a medal for participation. Good enough is what all the long-lived things have in common.
The rest is palaeontology."
- James McInerney, from "Good Enough." James McInerney Substack, 9 June 2026.
BRAND NEW!
As part of The Poetry Project, I am excited to announce a collaboration with the super talented Maddie Sovak who has voiced my poem 'Crying in the rain' giving a powerful, emotional performance! Love it! Thank you Maddie #jamesmcinerney #poetry #poem #thepoetryproject #actor #actress #mentalhealth
https://youtu.be/4TF27ZzYUhw?si=Mp7IqHUT1TWOdmd8
Thank you so much to the awesome @jamesmcinerneyofficial for the poetry books. He’s a beautiful writer and I’d suggest reading his works for some magic poetry in your life.
