In order to engage in a discussion of the applicability of mind to the brainless sea urchin, an agreement on a definition of brain and mind must be reached. We wonder if there is some way to explain the workaday life of the sea urchin without even a semblance of a brain; to live an existence that requires cogent decisions to meet its perilous sea-floor environment.
Does a Mind Really Need a Brain? The Beastly Echinoderm (sea urchin) thinks, yet it doesn’t have a brain!
What is a mind? In order to engage in a meaningful discussion of the applicability of the concept of mind to the brainless sea urchin, a consensus must be reached as a general-definition of two non-synonymous terms, brain and mind. For purposes of this writing I define ‘brain’ as a nerve ganglia consisting of a soft, convoluted mass of gray and white matter that serves to control and coordinate mental and physical actions. And further, for this writing, I define ‘mind’ as the res cogitans of Descartes, a mental process, presumably generated by the brain, rather than a physical substance, i.e., the mind is a mental state of thinking. We might wonder if there is some way to explain the business-like workaday life of that little beast, the sea urchin, that without even a semblance of the nerve ganglia that we call a brain; lives an existence that requires cogent decisions (without a brain) to meet its perilous sea-floor environment. To explain this paradox we might ask if there is an explanation other than in terms of grey and white physical substance. Further, how might these two approaches, given their entirely differing ontological nature, possibly relate to the mind-body problem of that little beast, the sea urchin, having thoughts?
I wonder, is attributing thoughts to a sea urchin being anthropomorphic? Anthropomorphism! What a word! Only a few years ago it was a sin to attribute human characteristics to nonhuman things. Certainly, it was condemnation aplenty to even utter the words “animal mind.” Nowadays, however, people even title books with those words. What has been happing? To answer the question, only a few years ago to ask, “What do you imagine happens inside the brains of animals?” would divide scientists into two groups. The comparative psychologists, behaviorists, and (to a large extent) ethnologists would enthusiastically describe rigid, inflexible mechanistic goings-on -- like the automatons of 1950s movies. The other group of scientists -- and really everybody else, scientist or not -- would reply: “Simple thoughts, I suppose, but I don’t see how we’ll ever know.”
How were these professionals so sure of their answers? They weren’t sure, of course, but they were carefully following the rule that science is supposed to abide by: accepting the simplest hypothesis until there is strong evidence of something more complex. Since evidence was minimal, the automaton theory won out, thus committing the fallacy of argumentum ad ignorantiam, arguing that something is true because no one has proved it to be false.
Donald Griffin set the ball rolling, leading to today’s interest in animal minds. In 1976 he wrote a book, “Animal Minds - Beyond Cognition to Consciousness,” cataloging animal behaviors that are not rigid and inflexible, actions that look suspiciously like our own, challenging readers to consider the possibility that not all animal behavior is mindless. Sometime later James and Carol Gould wrote, “The Animal mind,” showing cases that look as if they would be hard for an automaton to cope with -- animals acting in ways that look conscious.
In this writing I propose to take the reader a step further, suggesting that there are certain animals that can act in ways that seem to imply some aspect of mind without the benefit of a brain. The brain being defined as physical, a part of a nerve system where the mind functions.
Consider the sea urchin as a case in point; each one is formed from a hard shell. The shell has five narrow sections, laid out like a star, pierced with what appears to be an infinity of channels through which pass moving organs, called “ambulacra,” which act as extensions in a system of suckers. The creature stretches them out and retracts them at will quite nimbly in order to move and roll along the sea floor.
This nectarine shaped shell is enveloped and bristly with moving spines -- fine mauve-green daggers -- that give it protection against the formidable and menacing jaws and pincers that wander around in the currents, hidden among the underwater shadows.
Sea urchins are potentially attractive settlement sites for barnacles and seaweeds and other sessile organisms. But surprisingly these small beasts, the sea urchins, can clean themselves, and no doubt there are plenty of marine vermin that would be delighted to take shelter if not sustenance from the sea urchin, however it manages a process of active antifouling that should be the envy of any yachtsman. The body surface between the spines is dotted with thousands of tiny beaks on stalks that bend over to snap at anything foolish enough to tickle its surface.
Next time you find yourself feeling uncharitable about the spines, don’t simply smash every sea urchin in sight, but prize one gently off the rocks and put in a bowl, with enough water to cover it. Beg or preferably steal a lens (a jeweler’s loop is good), and view the surface of a sea urchin, it is a truly wondrous sight. Even without a lens you should be able to see that there is a lot more to a sea urchin than a mass of spines. Long, thin, snakelike tube feet extend between the spines and stick to the glass or to the bottom of the bowl. This is how sea urchins hang on to the rocks, and how they move about. Each tube foot is water filled, hollow and extended by pressure from within. It can bend, and wave to and fro until a contact is made, whereupon the end of the “foot” pulls in to make a minuscule sucker that grips the rock while the foot contracts and pulls. The pull of several hundred tiny feet can hold the urchin tight to the rocks, even in the wave surge of a gale.
The sea urchin’s mouth is on the lower side, directed toward the ground and armed with five protruding teeth, known as “Aristotle’s lanterns,” which serve as much for tearing apart prey, mollusks, or branches of kelp, as for digging its shelter on the sea bottom.
The intriguing problem with the sea urchin is that as soon as it starts to move about, is how the activity of several hundred tube feet can possibly be coordinated, for the animals have no detectable brain. Instead, a network of nerve cells is more or less concentrated along the underside of the five radii that define the symmetry of the urchin. The five radii converge on a ring of nervous tissue around the mouth of the animal. But that is all. No ganglia, no central control point as we are used to finding with more orthodox animals. So how is coordination achieved? How does a sea urchin decide which way to go off for a browse today, let alone find its way home afterwards?
One can get a mesmeric inkling of some of its functions from simple experiments while one has the beast in a bucket. Poke the surface of the urchin gently, but repeatedly, with the tip of a toothpick. The little snapping beaks and then the spines turn towards the point touched. Carry on and the effect gradually spreads, farther and farther over the surface of the sea urchin. These are local, reflex actions of course, but wait... soon hundreds and hundreds of tiny feet will be set in motion, and like a regiment of soldiers will march the beast away from the source of annoyance. One might reasonably conclude that there was some sort of brain in the mouth region giving orders, but even microscopic examination fails to reveal anything remotely resembling a brain.
So... we can conclude that a sea urchin functions as a democracy of reflexes (the older text books talk of a “republic of reflexes”), and it works! From this I further conclude that the sea urchin’s actions are governed by a republic of the mind. The nature of the sea urchin’s response to events in his life certainly suggests the function of mental properties and consciousness. I recognize that my conclusions give rise to difficult problems and questions. In this writing I merely attempt to suggest a little broadening the definition of the word “mind,” and also to suggest some questions to which I won’t attempt to provide answers.