Down in the octopus's garden, beneath the waves, evolution has been conducting experiments that would never have received ethics approval at a modern university. Take an animal, give it eight arms, remove the bones, cover the arms in suckers that can both touch and chemically sense the world, distribute much of the nervous system throughout those arms, and then see what happens. The result is the octopus, one of the strangest demonstrations that nature did not receive the memo saying intelligence had to be organised the way it is in humans.

As WIRED reports, an octopus has roughly 500 million neurons, and more than two-thirds of them are associated with its eight arms rather than concentrated in its central brain. The arms are interconnected through a nerve ring and possess an extraordinary capacity for local sensory processing and motor control. They can explore, manipulate and respond to their surroundings with considerable autonomy rather than waiting for the central brain to micromanage every muscular contraction. The suckers themselves provide extraordinarily rich tactile and chemical information.

This is sometimes popularised by saying that the octopus has "nine brains": one central brain and eight little brains in the arms. That makes a wonderful headline but should not be taken too literally. An octopus arm does not sit around contemplating Descartes while another arm reads Nietzsche. What the animal really possesses is something perhaps more interesting: a highly decentralised nervous system in which substantial computation occurs locally. Research into octopus arm behaviour suggests that the central brain can issue relatively general instructions while peripheral circuitry handles much of the messy business of turning those instructions into movement.

This makes excellent evolutionary sense. Try controlling an octopus arm from first principles. There are no elbow and wrist joints conveniently restricting movement to a manageable collection of angles. The arm is a muscular hydrostat capable of bending, twisting, shortening and elongating in an enormous variety of configurations. If the central brain had to calculate the precise position and contraction of every piece of eight such arms before doing anything, the unfortunate octopus might starve while completing the mathematics required to pick up breakfast.

Evolution found another solution: delegate.

Humans should immediately recognise the danger in this idea.

Imagine waking tomorrow morning to discover that your arms had acquired octopus-style distributed intelligence. Not consciousness necessarily, but enough independent processing to interpret broad objectives and get on with the job. You wake and think, "Coffee."

Normally this requires several tedious intermediate operations. Get out of bed. Walk into kitchen. Find mug. Put coffee in mug. Boil water. Pour water.

Not anymore.

Your right arm hears "coffee" and swings into action while the rest of you is still considering whether existence is worthwhile before 6 am. Your left hand meanwhile has independently concluded that toast would complement the coffee. Unfortunately, your stomach has communicated an entirely different preference and your right foot is already heading towards the refrigerator.

Human civilisation would change overnight.

Office productivity would explode. Why should the brain waste valuable time typing? Tell the left hand to answer emails while the right hand prepares the quarterly report. The central brain can meanwhile concentrate upon genuinely important matters such as watching YouTube.

Students would become terrifying.

"Did you write this essay yourself?"

"Certainly."

"Then why does the first half defend Kant and the second half attack him?"

"My hands disagree."

Universities would need entirely new academic integrity policies. Collaborative work would become philosophically complicated when all the collaborators occupied the same body. An examination candidate caught consulting notes under the desk could protest that he personally knew nothing about it. His left hand had acted independently.

Lawyers would have the greatest time of all.

"Your Honour, my client admits that his hand took the wallet, but denies that his central nervous system authorised the transaction."

The judge peers over his glasses.

"Are you advancing an autonomous-limb defence?"

"Precisely, Your Honour."

"Was the defendant's brain aware of what his hand was doing?"

"We submit that this is a question for the jury."

Politics would become even better. A politician could sign two contradictory promises simultaneously and mean both of them. One hand signs a pledge never to increase taxes while the other approves the tax increase.

Asked about the contradiction at a press conference, the minister could respond: "Those are operational matters for my peripheral nervous system."

Parliament would immediately establish a Senate Inquiry into Rogue Appendages.

Romance could become hazardous. Imagine reaching across the dinner table to hold someone's hand, only for your own hand to decide that the relationship is moving too quickly. Worse, perhaps your left hand likes the person but your right hand does not. Human beings currently struggle to maintain relationships with one brain involved. Adding semi-autonomous limbs seems unlikely to improve matters.

Sport would enter another dimension. A boxer could formulate strategy centrally while each fist made tactical decisions independently. A goalkeeper could dive one way while his hands reconsidered the available evidence. Tennis players could conduct doubles matches alone.

Cricket might finally become interesting to Americans once a batsman could argue with his own bat hand.

Then there is eating. An octopus can use different arms in extraordinarily flexible combinations because local neural machinery deals with much of the sensory-motor workload. Give humans comparable capacities and dieting would become impossible.

The brain says salad.

The right hand reaches for the chocolate cake.

"Stop that."

The hand continues.

"I am the central nervous system and I am ordering you to put down the cake."

The hand has considered the evidence and rejected central planning.

Perhaps this is why evolution did not give humans eight independently capable arms. Democracy is difficult enough with millions of voters without holding elections inside every citizen.

Yet underneath the jokes lies a profound scientific and philosophical lesson. The octopus demonstrates that sophisticated behaviour does not require precisely the architecture that evolution produced in vertebrates. Our nervous system is highly centralised by comparison. We therefore intuitively imagine intelligence as something happening inside the head, with the brain as chief executive and the body as obedient machinery.

The octopus makes that metaphor look provincial. Its evolutionary lineage diverged from ours hundreds of millions of years ago. Cephalopods therefore represent something approaching an independent evolutionary experiment in producing behavioural complexity. Nature arrived at sophisticated learning, exploration and problem-solving through an architecture strikingly unlike the vertebrate plan.

The consequences are already influencing robotics. Engineers interested in soft robots face something resembling the octopus's original evolutionary problem: how do you control flexible structures possessing huge numbers of possible configurations without requiring one central computer to calculate everything? Researchers are consequently experimenting with octopus-inspired distributed control systems in which local sections handle local problems while coordinating their behaviour.

The octopus therefore offers more than a biological curiosity. It presents an alternative engineering philosophy: do not necessarily build one enormous controller and make it responsible for everything. Push intelligence outward. Allow local systems to process local information. Coordinate them sufficiently to produce coherent behaviour.

Artificial intelligence researchers should perhaps keep an eye on the aquarium. And philosophers certainly should. If information processing responsible for intelligent behaviour can be spread so extensively throughout an animal, exactly where is the animal's mind? Is the octopus principally the creature inside the head directing eight sophisticated tools, or is the relevant cognitive system the entire animal? The question becomes especially interesting because the arms do not merely execute detailed commands sent from headquarters. Much sensory information is processed peripherally, while communication between central and peripheral systems is constrained.

The octopus does not answer the philosophical problem of consciousness. We should resist turning fascinating neurobiology into claims stronger than the evidence warrants. But it certainly attacks one comfortable human assumption: that our particular arrangement represents the obvious way to build a mind. Evolution apparently disagrees.

There are many ways of solving a problem. Humans built an enormous central processing system and placed it inside a skull. The octopus spread much of the work around the body and let eight extraordinary arms get on with it.

God's creation never ceases to be amazing!

https://www.wired.com/story/octopus-arms-distributed-intelligence-nine-brains/