Philosophy isn't natural science, that much is certain. But its relation to the sciences has been fraught — at least since science broke off from philosophy and became its own family of disciplines back in the 17th century.
The very features of natural science that are markers of its success — specialization, experiment, mathematical tools, progress — are absent, or take a very different form, in philosophy. My own view is that philosophical problems are not empirical or scientific ones, but that they live cheek by jowl with them. Philosophy and empirical science are in constant dialog and a laboratory is as good a place as a seminar room to engage philosophy.
Peter Godfrey-Smith, whose new book is my topic today, is not the first philosopher to go even farther afield than the laboratory in pursuit of nature's secrets. Daniel Dennett, to name one of Godfrey-Smith's avowed heroes, went to Kenya to study the vervet monkey in its natural habitat.
Still, I think it's worth pausing and taking delight in the stunning image of a philosopher descending the ocean blue in his quest to find other minds and to understand how they work!
Other Minds: The Octopus, The Sea, and The Deep Origins of Consciousness is not travelogue or tale of adventure in the great outdoors. It is a work of philosophy. There is no story, but there is an argument: Animal life is multi-cellular. Many hundreds of million years ago, "cells that were once organisms in their own right began to work as parts of larger units." But this required coordination. The means of exchange or mutual influence that had once enabled distinct unicellular individuals to communicate, or at least interact, were now deployed within the boundaries of the more complex multi-cellular beast. "Sensing and signaling between organisms gave rise to sensing and signaling within them," as the book notes. This, in turn, over evolutionary time, becomes the basis of the nervous system and, eventually, intelligence — and even consciousness itself.
Godfrey-Smith has a lot to say about the evolutionary history of animals and even about how, from humble beginnings, we get human beings, along one lineage, and the octopus, along another. But I wish he had said something more about the mystery — for that's what it is, at the heart of his story — of understanding how a clump of individuals gets put together in such a way as to become not just a collection of coordinated individuals but a genuinely new unity. Animal unity is something special. And, if he is right, it may be the key to understanding why there are nervous systems and, so, why there are animals like the octopus and like us.
Later on in the book, Godfrey-Smith remarks that trees and other plants seem to exhibit a kind of unity different from, and intermediate between, that of mere collections and that which is displayed by animals. The tree is an agglomeration, in the sense that if you cut a part away and plant it, you get a new tree. An animal, in contrast, is some kind of an essential unity.
The language of Other Minds is calm, spare and exact. It serves as a useful primer on more than one topic — the history of animals, the cognitive powers of cephalopods, the theory of consciousness, the environmental dangers posed by overfishing and the degradation of the waters. It gives us a remarkable description of the octopus settlement or compound — community? — that he and his colleagues studied closely over a long period in waters off Sydney. He speculates that some piece of human detritus, something metal, fell to the sea floor and it provided an artificial shelter or den for an octopus; the shell remains of scallops cast aside by the octopus then provided a ground better suited for octopus dens than the sandy bottom of the sea floor. This attracted other octopus, he continues, who, in turn, in the normal course of events, laid down more shell flooring — thus further enhancing the habitat and drawing more animals to the spot. Godfrey-Smith wonders whether Octopolis, as they dubbed the small piece of ocean ground, doesn't give a glimpse of a possible octopus future in which otherwise fairly solitary creatures develop something like real social groups.
Octopus sociality is made out to be something of a puzzle in this book. Like cuttle fish, the octopus are capable of fabulous and rapid-fire changes of skin color. How they do this is a mystery. Not because the mechanisms of pigment change are poorly understood, but because these animals are (widely believed) to be color blind. Of what use to a color-blind potential mate is a display of color? Actually, the puzzle is deeper even than this. The octopus also changes its color to camouflage itself. But how can it adjust its own color to the surrounding scene if it can't perceive the colors of things around it? Godfrey-Smith has an ingenious and plausible answer to this question.
But surely the most surprising, indeed, the truly shocking fact about the octopus that comes up in these pages is that most species of octopus only live 2 to 4 years. Godfrey-Smith frames this as a problem for evolution. Why would evolution go to the expense of giving short-lived animals such magnificent smarts? The octopus, as Godfrey-Smith explains, is a curious, clever and inventive creature; it has good eyesight (aside from the color vision) and is capable, in captivity, of recognizing and keeping track of individual people. Moreover, the octopus, and to some degree also the cuttlefish, are the only examples of big brains in the whole universe of invertebrate species. What's the point, if the animals have such a short lifespan?
Drawing on well-known evolutionary ideas, Godfrey-Smith offers a brilliant answer. I won't give the details here, but the basic idea is pretty straight forward. Animals who live to an old age are less likely to carry mutations of the sort that are likely to kill them when they are young. Indeed, animals who suffer mutations whose harmful effects strike early on are unlikely to have no offspring or are unlikely to have as many children as animals who live longer. It follows that there will be a tendency for whatever destructive effects of mutations there may be to manifest themselves, over evolutionary time, later and later in life.
Of course, just how long a species will tend to live will reflect environmental conditions as well. Vulnerability to predators, for example, will cull parents who wait too long to have kids. Lifespan is thus likely to be tuned evolutionarily by this kind of environmental risk factor.
Back to the octopus. Godfey-Smith explains: "They have ended up with their unusual combination: a very large nervous system and a very short life. They have the large nervous system because of what those unbounded bodies make possible and the need to hunt while being hunted; their lives are short because their vulnerability tunes their lifespan. The initially paradoxical combination makes sense."
This is an ingenious and plausible account both of why animals don't live forever, even though their cells are continuously made anew, and also of why, in particular, the octopus has such a short life span.
But it is not quite the answer I was looking for. Or, rather, it is the right answer to the wrong question. What makes the fact that octopus die so young so very shocking is not the evolutionary puzzle of it, I think, but rather the fact that there is something in itself mind-bending and incomprehensible about the very idea that so much intelligence and understanding could be achieved in such a short life. For us, it seems, thought, understanding, wits, are tied up with experience and, so, with time. Octopus nous is freakish, like something out of science fiction.
Which ties up with another theme of Other Minds. Godfrey-Smith remarks at the outset that contact with an octopus is the closest most of us will ever come to an intelligent alien. For the most part, reading this book, I had the feeling that this was not so. It isn't that the octopus isn't different from us. Long gangly arms, eight of them; a boneless body that shifts shape and changes color. All this is strange. And there is no disputing the evolutionary facts. You have to go back 600 million years to meet the bilateral, light-sensitive worm who is the common ancestor of both humans and cephalopods. This is a being whose cleverness took shape as a result of a very different history than that of ourselves.
And yet, the octopus doesn't come across as all that exotic or even all that wild. And this shouldn't be that surprising when you stop to think that intelligence, wit, rationality, these are, as Dennett has stressed, interpretive notions. To see someone or something as intelligent is to view it as conforming to a certain way of acting. Rational beings are the ones that do what they should in light of what they need given what they know. The octopus, however playful or curious, is a smarty pants and for that reason doesn't seem that remote at all.
Until we come up against the startling fact of the brevity of octopus life, that is. It is here that I had the vivid sense that in encountering the octopus we are brought into contact not merely with an intelligent alien, but a truly alien intelligence.
Alva Noë is a philosopher at the University of California, Berkeley where he writes and teaches about perception, consciousness and art. He is the author of several books, including his latest, Strange Tools: Art and Human Nature (Farrar, Straus and Giroux, 2015). You can keep up with more of what Alva is thinking on Facebook and on Twitter: @alvanoe