Book review

Other Minds: The Octopus and the Evolution of Intelligent Life

by Peter Godfrey-Smith

Other Minds by Peter Godfrey-Smith

Octopuses have eight legs, we all know that. How many hearts do they have? Turns out they have three. Now, how many brains? Well, it turns out the answer to that is complicated… very complicated. And that has huge implications for how smart we think octopuses might be, along with a few of their close relations like some squids, together known as cephalopods. It also starts to nudge into an even more interesting space: that of whether octopuses are conscious or not. Because if they are, the implications are huge, and that’s what this book mainly sets out to explore:

“Cephalopods are an island of mental complexity in the sea of invertebrate animals. Because our most recent common ancestor was so simple and lies so far back, cephalopods are an independent experiment in the evolution of large brains and complex behavior. If we can make contact with cephalopods as sentient beings, it is not because of a shared history, not because of kinship, but because evolution built minds twice over. This is probably the closest we will come to meeting an intelligent alien.”

It’s a truly fascinating space to think about, and this book did a good job of introducing me to various aspects of it. The early chapters take you through the ancient evolutionary history that lead to both humans and the octopus. We go all the way back to the Ediacaran, from about 635 to about 542 million years ago. Life seems to have been very peaceful then, with creatures grazing on mats of vegetation in the early oceans. All sorts of weird things were out there:

“body forms that have since been entirely abandoned by evolution – three-sided and four-sided designs, some with quilted arrangements of plant-like fronds.”

Then some animal worked out that eating other animals gave you a lot more nutritional value than grazing, and we were in a whole new game. This is the Cambrian era of prehistory:

“During the Cambrian the relations between one animal and another became a more important factor in the lives of each. Behavior became directed on other animals – watching, seizing, and evading. From early in the Cambrian we see fossils that display the machinery of these interactions: eyes, claws, antennae. These animals also have obvious marks of mobility: legs and fins. Legs and fins don’t necessarily show that one animal was interacting with others. Claws, in contrast, have little ambiguity.”

One way to deal with this was to grow a hard shell, and hide within it, or to grow hard body parts and use them to leverage muscles. This was the path our ancestors chose. The other was that of the octopus:

“An octopus has almost no hard parts at all – its eyes and beak are the largest – and as a result it can squeeze through a hole about the size of its eyeball and transform its body shape almost indefinitely. The evolution of cephalopods yielded, in the octopus, a body of pure possibility.”

To use that possibility, the octopus has many more neurons than comparable creatures – about 500 million, close to the range of dogs, and very much larger than all other invertebrates. But these neurons aren’t largely collected in one place, as with vertebrates:

“When vertebrate brains are compared to octopus brains, all bets – or rather, all mappings – are off. There is no part-by-part correspondence between the parts of their brains and ours. Indeed, octopuses have not even collected the majority of their neurons inside their brains; most of the neurons are found in their arms.”

This is where it starts to get weird. The arms have nearly twice as many neurons as the central brain. “Each individual sucker on an octopus’s arms may have 10,000 neurons to handle taste and touch. Even an arm that has been surgically removed can perform various basic motions, like reaching and grasping.”

And still they are very smart – “smart in the sense of being curious and flexible; they are adventurous, opportunistic”. Examples abound:

“When vertebrate brains are compared to octopus brains, all bets – or rather, all mappings – are off. There is no part-by-part correspondence between the parts of their brains and ours. Indeed, octopuses have not even collected the majority of their neurons inside their brains; most of the neurons are found in their arms.”

So how does this all work? The octopus, we discover, is “suffused with nervousness; the body is not a separate thing that is controlled by the brain” – the brain is the body, or perhaps better even to say the body is the brain. If it has a language, it seems to be a language of colour and patterns, for octopuses can also produce a remarkable range of colours and patterns on their body, changing these in a second or less if needed. They do this not only for camouflage, but also, so far as we can tell, to communicate with other octopuses. Our exploration of this has barely begun, as we gather data from octopuses in the wild, but it’s certainly used for mating, and quite likely used for dominance displays.

Finally, we touch on the question of why an octopus might need intelligence like this? Neurons are very expensive things to run, from an energy point of view. Many octopuses only live for two years. Why would such a creature need such a sophisticated capability? We do not yet know.

This is a tantalizing book. The author, based on many hundreds of hours of personal observation in the ocean, and building on decades of work from others, makes a very strong case for octopuses as intelligent creatures, even as conscious creatures – as conscious as your family pet, perhaps. But different, too, with a distributed intelligence of a completely different kind than cats, dogs, and humans. There is much more we can learn about intelligence, about consciousness, about what it is to be human rather than a crab or a cat or a cephalopod, from these eight legged, three hearted, creatures with their distributed intelligence and language of colour.

Book review


A Brief Guide to the Fundamental Mystery of the Mind

by Annaka Harris

Conscious by Annaka Harris

This is a brief introduction to the mysteries of consciousness, with much to commend it. It starts a conventional definition, after Thomas Nagel: “An organism is conscious if there is something that it is like to be that organism”. From this starting point, Annaka Harris takes us via an interesting series of viewpoints to a view of consciousness that she acknowledges isn’t really the mainstream view – that of “pan-psychism”, which is that consciousness may be an inherent quality of matter even down to the smallest levels – electrons may be, in some tiny atomic way, conscious. From these small components, consciousness as we know and experience it as humans is produced.

The route to this conclusion covers some ground that may be familiar to many readers, such as David Chalmers’ “philosophical zombies” – people who look and act exactly like you or I, but who (by definition) do not have conscious experiences. It also covers some territory that was new to me, such as the discussion about trees and how they seem to communicate via their roots tapping into underground mycorrhizal networks. This was fascinating to me, and lead me off to all sorts of interesting searches – this was a nice summary I found.

The argument is overall well put, but I felt there were difficulties that had either been skipped for simplicity, or simply weren’t acknowledged. For example, Harris says that “as far as consciousness is concerned, there is nothing, then suddenly, magically, at just the right moment …. something!”. It’s not clear to me that this has to be the case. Introspectively, I am conscious at some moments to a greater degree than others. When I fall into a deep sleep, does my consciousness finally switch off at a defined point, or is it more like sunset on a cloudy day: it gets darker and darker, and eventually it’s definitely completely dark, but there was no one moment when the last light was extinguished. It seems to me consciousness is more like this – continuous, not discrete. And if the claim is that it’s discrete, I’d hope for a discussion of the point.

As another example, one of the traditional arguments against panpsychism is discussed in the book – the “combination problem”:

The problem is that this is very difficult to make sense of: “little” conscious subjects of experience with their micro-experiences coming together to form a “big” conscious subject with its own experiences

Harris argues that this problem isn’t present in versions of panpsychism in which consciousness is a fundamental feature of the universe, as consciousness is not interacting with “itself”, as it would be if it were combining. Think of gravity: individual atoms have a tiny amount of mass, and thus of gravitational attraction, and they can combine perfectly happily to produce a large planet with its own gravity.

This argument, it seems to me, can apply just as well to the “emergent” view of consciousness, where consciousness emerges as the appropriate kinds of information processing capabilities combine in an appropriate way. But Harris has already dismissed the possible emergence of consciousness by saying that it doesn’t really explain it at all:

…when scientists assume they have bypassed the hard problem by describing consciousness as an emergent property – that is, a complex phenomenon not predicted by the constituent parts – they are changing the subject …. If some matter has experience and some doesn’t (and some emergent phenomena entail experience and some don’t), the concept of emergence as it is traditionally used in science simply doesn’t explain consciousness.

But simply defining consciousness as something that all matter has, it seems to me, isn’t a good way out of this problem. Announcing that everything has consciousness, down to electrons and protons, and therefore some things get to be what we call conscious, is either a way of hiding from the hard problem (“everything is conscious, so no wonder we are”), or just causes the emergence problem to emerge in a different place (how does what we historically cause consciousness appear from combining a lot of this subatomic consciousness – and you can’t use emergence as you’ve already dismissed this!).

In the end, there was a lot to like about this book, and I found it hard to pick a final star rating. This is a three-and-a-half star book for me. Lots to like, some interesting new ideas, really nice to see a readable book on such a complex issue, although it was too short to do enough justice to all of its subject matter, even for a self-confessed “brief guide”. In the end, I have gone with four stars, to encourage Ms Harris to write more on this, and to guide readers to an interesting book.