Peter Godfrey-Smith’s “Other Minds”: Book Review, Notes, and Analysis

Poor Ash’s Almanack > Book Reviews > Science + Engineering + Math > Biology

Peter Godfrey-Smith's "Other Minds" is an excellent book.
Other Minds is the single best book I’ve found on the “trait adaptivity” mental model, tracing the development of octopus intelligence. Click the picture to buy it on Amazon.

Overall Rating: ★★★★★★★ (7/7) (life-changing)

Per-Hour Learning Potential / Utility: ★★★★★★★ (7/7)

Readability: ★★★★★★★ (7/7)

Challenge Level: (2/5) (Easy) | ~204 pages ex-notes (272 official)

Blurb/Description: Professor and avid diver Peter Godfrey-Smith analyzes the curious case of octopus intelligence, delivering engaging and thought-provoking insights on a variety of scientific topics.

Summary: This easy-to-read, fast-paced book is that rarest of birds (or octopi): it seriously addresses important scientific and philosophical questions without delving into technical minutiae or devolving into parched-bone academic prose.  Godfrey-Smith combines equal parts solid writing, fascinating/intriguing details about octopi, and an array of thought-provoking, learning-rich scientific insights (with a little philosophy, of the interesting sort, for good measure.)

Highlights: I picked this book up on a lark because I’ve always thought octopi were cool; I wasn’t sure what to expect from it.  It blew me away on every level: the writing, while not as thoroughly witty as Richard Thaler’s or snappy as Jonathan Waldman’s, was astonishingly clear and engaging and not at all what you might expect when you hear “philosophy professor.”  The scientific explanations presented were cautious, balanced, and multifaceted, offering a variety of learning lessons and leaving plenty of room for thought.  The investigation into what it feels like to be an octopus was as intriguing as I thought it would be.  Ultimately, I was impressed by the breadth and depth of this book and will treasure rereading it in a way I don’t with many other books.

Lowlights: There’s really nothing I didn’t like about this book.  Other than Godfrey-Smith neglecting to mention that octopi are potentially venomous and it might not be a fantastic idea to go holding their hands on tours of the ocean floor.

Mental Model / ART Thinking Points: social connectiondisaggregationnonlinearityfeedbackn-order impactsarms racetrait adaptivitybottlenecks, novelty-seeking, schematradeoffconditioningstructural problem solvingagencyhyperbolic discountingmemory,

You should buy a copy of Other Minds if: you want a learning-rich book that covers a lot of important concepts via an interesting topic in a highly engaging way.

Reading Tips: This is a very easy, engaging, straightforward read.  The only thing I would say is that it’s a book wherein readers will likely benefit from a decent amount of previous knowledge of mental models like schema, critical mass, and n-order impacts, as well as concepts like evolution, trait adaptivity, and so on: while any reader could pick up this book and get something out of it, many of the lessons are substantially more accessible with some previous knowledge of the topics.  As such, while I really love this book, it’s probably one to put somewhat later rather than earlier on your priority list (if the concepts mentioned aren’t intimately familiar to you).

Pairs Well With:

This Talk at Google by Peter Godfrey-Smith.  It’s a good supplement to  / review of the book, including some cool videos of Octopolis… and it highlights his accent.

The Genius of Birds ( Bird review + notes) by Jennifer Ackerman – an exploration of avian intelligence that is also delightful, with wonderful learning lessons / mental models.

The Violinist’s Thumb ( TVT review + notes) by Sam Kean – a wide-ranging, if occasionally slightly ADD, exploration of genetics

Curious by Ian Leslie ( C review + notes) – a book on the rarely-discussed topic of curiosity; the first half, at least, is solid (the second half less so)

The Power of Habit by Charles Duhigg (PoH review + notes) – a fascinating book on the ways in which habit can guide our behavior below the level of executive function

The Design of Everyday Things by Don Norman (DOET review + notes) – one of ACM’s “seven-star” book recommendations, which covers (among other things) discussion analogous to the “embodied cognition” discussion referenced in Other Minds

10% Happier by Dan Harris ( 10H review + notes) – a practical, funny how-to guide for quieting the “inner voice” that makes us uniquely human… sometimes in ways we wish it wouldn’t/

Reread Value: 4/5 (High)

More Detailed Notes + Analysis (SPOILERS BELOW):

IMPORTANT: the below commentary DOES NOT SUBSTITUTE for READING THE BOOK.  Full stop. This commentary is NOT a comprehensive summary of the lessons of the book, or intended to be comprehensive.  It was primarily created for my own personal reference.

Much of the below will be utterly incomprehensible if you have not read the book, or if you do not have the book on hand to reference.  Even if it was comprehensive, you would be depriving yourself of the vast majority of the learning opportunity by only reading the “Cliff Notes.”  Do so at your own peril.

I provide these notes and analysis for five use cases.  First, they may help you decide which books you should put on your shelf, based on a quick review of some of the ideas discussed.  

Second, as I discuss in the memory mental model, time-delayed re-encoding strengthens memory, and notes can also serve as a “cue” to enhance recall.  However, taking notes is a time consuming process that many busy students and professionals opt out of, so hopefully these notes can serve as a starting point to which you can append your own thoughts, marginalia, insights, etc.

Third, perhaps most importantly of all, I contextualize authors’ points with points from other books that either serve to strengthen, or weaken, the arguments made.  I also point out how specific examples tie in to specific mental models, which you are encouraged to read, thereby enriching your understanding and accelerating your learning.  Combining two and three, I recommend that you read these notes while the book’s still fresh in your mind – after a few days, perhaps.

Fourth, they will hopefully serve as a “discovery mechanism” for further related reading.

Fifth and finally, they will hopefully serve as an index for you to return to at a future point in time, to identify sections of the book worth rereading to help you better address current challenges and opportunities in your life – or to reinterpret and reimagine elements of the book in a light you didn’t see previously because you weren’t familiar with all the other models or books discussed in the third use case.

Page 5: Octopuses (hereinafter, I choose to refer to them as “octopi” because, well, I can) show an unusual sense of engagement with humans.  Cuttlefish do as well, albeit at a slightly lesser level.

Pages 8, 9: The last common ancestor between us and octopi, an underwater worm-ish-thing, was apparently 600 million years ago; from there, life split off into two categories that (eventually) become vertebrates and many invertebrates (directionally accurate; not technically precise.)

Godfrey-Smith notes regarding  social connection that while:

“some insects and spiders engage in very complex behavior, especially social behavior, they still have small nervous systems.”  

In contrast, cephalopods – i.e. octopi, cuttlefish, and squid – represent:

“an island of mental complexity in the sea of inverterbrate animals.”

Why is this important? Because it means that the intelligence and large nervous systems of octopi evolved independently of that in humans/mammals/vertebrates, thus perhaps providing us with a unique perspective into how these systems work – and how they can work differently.

Pages 16, 18 – 20: Godfrey-Smith discusses the progression of input/output systems in single-celled organisms, from the simple, rather binary food-sensing system of E. coli (moving in a straight line if its current vector is leading to higher concentrations of food, moving randomly otherwise to find a new vector) to the more complicated sensing done by other organisms via receptors sensitive to chemicals produced by themselves as well as by other cells.  This is an important precursor to cellular signaling in multicellular organisms, and also a neat application of  disaggregation.

One interesting example is quorum sensing: in an example of a natural critical mass / critical threshold ( nonlinearity), bacteria living inside a Hawaiian squid produce light to cancel the squid’s shadow and make it a more effective predator, but they only do this if there are enough other bacteria around, as it’s not worth doing if there aren’t enough bacteria to create enough light.

Pages 22 – 23: For a multicellular organism to be able to function, the cells have to be able to communicate.  One of the major ways this happens is via the nervous system, comprised of neurons with an action potential that sprays chemicals into the gap between it and the next neuron, which detects the chemicals.

Relative to other kinds of signaling, nervous systems allow communication that is very rapid and targeted.  The downside?  It’s energetically expensive; the human brain consumes roughly a quarter of our calories (which, as discussed on pages 221 – 230 of The Violinist’s Thumb – TVT review + notes – means that natural selection can, under certain circumstances, actually favor less intelligent animals.

Pages 33 – 37: Why did the Cambrian Explosion (the period when biodiversity exploded) happen?  Godfrey-Smith posits that one (of many) potential contributing factors was feedback effects,  n-order impacts, and an  arms race: whereas previously, animals had not interacted very much:

“from the early Cambrian onward there was definitely predation, together with everything that predation encourages.”  

This led to extreme selection pressure on the hunted to improve their defenses, which led to selection pressure on the hunters to become better predators, and so on and so forth.  It turns out that “bilaterian” (symmetrical animals with a left and a right side) animals are best suited to mobility and the consequent complex behavior that mobility enables.  

The most “intelligent” non-bilaterian is the box jellyfish, which can apparently navigate by watching landmarks on the shore.  (They make swimming off certain beaches in Northeast Australia quite dangerous.)

In an example of bottleneckstrait adaptivity, and feedback effects / n-order impacts, Godfrey-Smith notes that:

“nervous systems evolved before the bilaterian body plan, but this body created vast new possibilities for their use.”  

The development of eyes allowed us to obtain far more sensory input than previously, but also necessitated the creation of a processing engine because it makes decisions more complicated (think about the complexity of an NFL wide receiver catching a football traveling in a parabolic arc, versus E. coli’s yes-no “is there more food here than where I was five seconds ago” decision algorithm for deciding whether to move in a straight line or in a random direction.

Pages 44 – 48: Octopi like touching humans when they encounter them underwater, apparently; here and elsewhere, Godfrey-Smith neglects to mention what I consider to be a moderately important fact: octopi are venomous (although it seems only one is actually very dangerous to humans).   

Godfrey-Smith discusses the evolution of mollusks, which over time gained shells that offered both protection and (via buoyancy) increased mobility.  Cephalopods, not needing their feet anymore, changed them into tentacles, which (combined with their siphons that allow them to get around) made them into fearsome predators.  

Oddly, however, cephalopods eventually gave up their shells, which enabled more mobility, but at an obvious cost / tradeoff (less protection).  Octopi are super mobile – they have no hard parts at all and can “squeeze through a hole about the size of its eyeball.”

There is a nice diagram on page 49.

Pages 50 – 52: Octopi are very smart – it is difficult to judge how much relative to various “smart” vertebrates like dogs – but they have very different nervous systems than we do.

Page 54: Octopi also have personalities.  This book enforced my earlier decision that I don’t want to eat octopi.  (Don’t ask me to enforce logical consistency on cows; I’m aware they have personalities too.)

Pages 55 – 59: Octopi can recognize individual humans (even if they wear identical uniforms).  One researcher noted that octopi know they are in an unnatural environment and the captivity affects their behavior.  They have displayed behaviors as precocious as purposefully disposing of perfectly edible food that they don’t like, shooting out the lights, escaping only when people aren’t looking, and so on.

Godfrey-Smith posits that, in some of the instances when octopi have been slow to learn via conditioning to push levers and so on, it may not be a case of lack of ability: it may be a case, a la the good Dr. James Lock in Jerome Groopman’s How Doctors Think (HDT review + notes), of an intelligent teenager who is bored in school.  Octopi engage in play: they will blow pill bottles around, and (both in the lab and in natural environments), are as novelty-seeking as we are.

Pages 60 – 64: Although most octopi are typically solitary due to the nature of their habitat in dens, they are capable of adapting to social environments, such as in the artificially-created “Octopolis” off the coast of Australia, wherein a bed of scallop shells (which was, to at least some degree, created by the octopi themselves, if not entirely intentionally) a colony of octopi live.  

They display some pretty interesting behavior; in one example, one octopus grabs the hand of a friend of the author’s, and takes him on a ten-minute tour around the ocean floor that ended at its den.  

Octopi demonstrate an interest in new objects, and use tools in advanced ways: on Page 64, Godfrey-Smith discusses how octopi use pairs of halved coconut shells as portable shelters.  He notes that the “compound” nature of their tool use is particularly unusual.  His interpretation about the distinctive feature of octopus intelligence:

“They are smart in the sense of being curious and flexible; they are adventurous, opportunistic.”

Pages 66 – 67, 69: Comparing and contrasting the nervous system of “chordates” (us, and anything else with a spinal cord) and the cephalopods, Godfrey-Smith notes the much-more distributed nature of the latter’s nervous system.  

Twice as many neurons are in an octopus’s arms (tentacles) as are in the brain; each arm can touch, smell, and taste.  As such, arms that are surgically removed can still function with a limited degree of autonomy.

Nonetheless, the central brains do work: octopi can learn to guide their arms (outside of water) using their eyes.

Pages 73 – 76: Octopi are more intelligent than, it would seem, nature demands.  They also have something human babies do not: i.e., object permanence.  Godfrey-Smith notes that:

smart animals handle the stuff of their world [by…] carv[ing] it up into objects that can be re-identified despite ongoing changes in how those objects present themselves.”

Or, in other words, having some sort of a schema.  Also, interesting biological information: octopi have three hearts that pump blue-green blood with copper, rather than iron, as the oxygen-carrying molecule.

Godfrey-Smith goes on to discuss the idea of “embodied cognition,” which reminds me of Don Norman’s discussions about human memory and design: essentially, the theory is a literal example of structural problem solving, an idea that:

“our body’s own structure encodes some information about the environment and how we must deal with it, so not all this information needs to be stored in the brain […] as Hillel Chiel and Randall Beer put it, an animal’s body structure creates both constraints and opportunities, which guide its action.”  

There’s a parallel of sorts in Design of Everyday Things from pages 123 – 125, where Norman discusses (using a Lego motorcycle as an example) how designed natural constraints can help:

“us determine how to operate something that we have never seen before[.]  We have no choice but to combine knowledge in the world with that in the head.  […] the visible affordances of the [Legos] were important in determining just how they fit together […] cultural and semantic constraints [SP: for example, where wheels go on a vehicle] provided strong restrictions on what would make sense for all but one of the remaining pieces […] constraints are powerful clues, limiting the set of possible actions.”

Godfrey-Smith agrees that the “different embodiment” of octopi has consequences for their different kind of psychology,” but disagrees that it explains much or all about the octopus, especially since (as discussed earlier) the octopus can sort of turn itself into whatever shape it wants.  Thought-provoking stuff.

Pages 78 – 81: Godfrey-Smith should be applauded (here and throughout) for tiptoeing on a very narrow tightrope when it comes to issues of sentience, consciousness, and what it feels like to be alive (in a different body).  

Most of the discussions by other authors I’ve seen on this topic are either reductionistic, deterministic, anti-agency arguments that ultimately provide no answers I find thought-provoking,useful, or fulfilling (Robert Wright’s The Moral Animal and Steven Pinker’s The Blank Slate are two books in that camp that I *wouldn’t* recommend; I couldn’t make it all the way through either of them).

On the flip side, there are the philosophical-not-empirical arguments that often tend toward mysticism or pointlessness: the kinds of questions and discussions that Richard Feynman, in The Pleasure of Finding Things Out, refers to as questions he “doesn’t know anything about” or even about “what the question might mean.”

In sharp contrast, Godfrey-Smith offers useful questions with useful answers: referencing Thomas Nagel, who apparently used the phrase “what it’s like” in “an attempt to point us toward the mystery posed by subjective experience,” Godfrey-Smith discusses that human life has a “feel,” and, seemingly, octopus life would also have a “feel” – although a much different one that for many reasons, including their totally different neural structures, could not be mapped onto our experiences in a like-for-like manner.

Godfrey-Smith discusses the interesting phenomenon of blind people with “tactile vision substitution systems” (cameras hooked up to some sort of physical stimulation device) eventually learning to perceive “objects located in space, not just a pattern of touches on their skin.”  

The important part, though, is this only occurs when the wearer is able to control the camera, to act and influence the incoming stream of stimulation.”

That seems important, though I’m not sure yet where to classify that.  Godfrey-Smith points out that “sensing and acting each affect the other,” –  i.e. feedback – which invalidates the historical philosophical perspective of a “stream of experience,” since it’s not just something coming at us – we can control our location in the stream.

Pages 83 – 87: Godfrey-Smith discusses the fascinating (and, at least for me, not previously explored) phenomenon of the problem of self-reference: if a fish sends out a pulse, how will it subsequently distinguish that pulse from something in the environment that it did not create?  

The idea is that there is a change in the environment caused by us, and we need to not react to that the same way that we would otherwise.  We accomplish that by sending a copy of the command; essentially CCing ourselves on the sent email, so we can “cancel out” the environmental impact.  

That is, in other words (mine, not Godfrey-Smith’s), why it feels different when someone sneaks up and puts a hand on your shoulder, vs. putting a hand on your own shoulder.

Godfrey-Smith goes on to discuss the idea of “perceptual constancies” – this is probably the more technical term for what I, crudely, referred to earlier as the idea of object permanence – he points out that we create a mental map (a schema, in some senses) that allows us to recognize, despite widely varying input (closeness, farness, light, dark, etc) that a chair in our dining room is still a chair.  (I’m extrapolating here.)

This is not, as it may initially seem, inevitable – Godfrey-Smith notes that experiments with pigeons, for example, suggest that if they learn something with one eye (one half of their brain), they don’t learn anything with the other half.  They don’t actually integrate their separate fields of vision, which is mind-bending to think about – imagine if half of your body didn’t talk to the other, in a way – imagine if you closed your right eye, read this with your left, and then were completely unable to remember or process the information!

Octopi are in between humans and pigeons in this regard.

Pages 88 – 91: Godfrey-Smith extends the discussion by noting that certain kinds of processing of visual information can actually occur without going through the “internal model” (schema-building) part of the brain.  

So we can actually get pretty far, functionally speaking, without the “internal model” (the meta-thinking) that allows us to have subjective experiences.  Citing research by neuroscientist Stanislas Dehaene, he notes that our conscious awareness is associated with the kind of processing needed to deal with time, sequences, and novelty.”

See also  cognition vs. intuition.

Pages 93 – 96: Some more thought-provoking discussion about the difference between being able to feel things and being human: experiments with fish and chickens suggest that they will seek out painkillers when in pain, even if it requires behavior they would otherwise not prefer.

Godfrey-Smith makes the analogy to white noise: experience “starts as an inchoate buzz” and, in its highest form, ends up as :

a close association with perception and control – with using what we sense to work out what we do […] subjective experience [arises from] the modulation of its state, from registering things that matter […] sentience has some POINT to it.  It’s not just a bathing in living activity.”


Pages 98 – 101: Godfrey-Smith reiterates that octopi are curious and novelty-seeking, sometimes (like humans!) to the point of “puzzling recklessness.”  In addition to being good at perceptual constancies and navigation, octopi can focus.

Page 103: the conclusion on the subjective experience of the octopus is that its arms are both part of the self and, in some senses, part of the environment, if we’re anthropomorphizing – in the sense that the brain can control them, but not too closely.

Pages 108 – 112: cephalopods such as the giant cuttlefish and the octopus apparently put the chameleon to shame..  How does it work?  Below the dermis are chromatophores, which contain colored chemicals and a couple dozen muscle cells that can “stretch the sac to make its color visible, or relax it for the opposite effect.”  In other words, they’re a bit like pixels.  

While there are chromatophores of various colors, there are also other kinds of reflecting cells like “iridophores” that create other colors (like greens and blues) by selectively reflecting certain wavelengths of incoming light.  (Nice diagram on page 111.)

Pages 113 – 118, 119, 121 – 124, 126: After some stunning pictures in the centerfold, Godfrey-Smith discusses the possible implications of inexplicable (i.e., not purposeful) color changes in octopi and cuttlefish.  The funny thing is that many cephalopods are actually color-blind.  While the mechanism is not known, and it’s not proven, Godfrey-Smith postulates that it may be a signaling mechanism (or at least an intriguing capacity therefore), which might suggest that octopi have the ability to think, somewhat like we do.

Pages 129 – 132: Referencing a book called “Baboon Metaphysics” by Cheney and Seyfarth, Godfrey-Smith discusses how baboons’ ability to combine knowledge of who with only three to four relatively simple kinds of calls allows them to figure out important power shifts: simple expression, but complex interpretation.  Kind of an emergence thing but not quite.

In cephalopods, in contrast, it’s the opposite: they have very exquisite and potentially precise signaling abilities that could portend a visual language, but fairly limited possibilities for interpretation.  

Godfrey-Smith calls octopi, squid, and baboons “unfinished,” with the potential for more (though he notes evolution is not goal-directed.”

Page 134: do octopi dream?  Dr. Matthew Walker might be interested in the answer – he notes in Why We Sleep (Sleep review + notes) that all animals known to man sleep.  Even worms.

However, REM sleep is less prevalent (not nonexistent, but operates somewhat differently) in aquatic mammals like dolphins, or in ones like seals that end up in the water.

Pages 138 – 143: Godfrey-Smith starts to contrast our minds with those of others: what is the purpose, and cause, of the inner speech, the “rambling commentaries, speeches we would like to give, or wish we’d given?” 

(For a more practical, less existential analysis of inner speech and how to quiet it down if it’s a bit too noisy, you can’t do better than 10% Happier by Dan Harris – 10H review + notes.  Also, Godfrey-Smith is a solid writer.)

Godfrey-Smith notes that, as discussed with the baboons, very complex things [including social behavior] go on inside other animals without the aid of speech.”  

Birds, similarly, can apparently retrieve stored food in order of perishability.  And some of them are curious, too.

(See Jennifer Ackerman’s “ The Genius of Birds” – Bird review + notes).

Similarly, chimps can sometimes work through novel problems without the aid of human-like internal language, and a French Canadian monk, “Brother John,” was still able to order off menus (in a limited way) even during episodes of complete (internal and external) aphasia.

Pages 143 – 146: so if language isn’t required for complex thought, what is it required for?  Godfrey-Smith goes back to the idea of an “efference copy,” which was mentioned earlier (without a name) in the discussion of us (my words) CCing ourselves on the emails we send.  It’s obvious how internal speech helps us with actual speech; it’s easy to see how this capability leads to the ability to have internal speech without external speech.  

Referencing both a Russian researcher and Daniel Kahneman, Godfrey-Smith posits that internal speech has a role in “executive control” – i.e. agency – and the “slow, deliberate” thinking, what Kahneman calls System 2.

Page 149: Godfrey-Smith notes that inner speech can be so overwhelming that some people use meditation to get away from it – again, a nice link to 10% Happier ( 10H review + notes).

Pages 151 – 152: Godfrey-Smith notes that higher-order thought, i.e. meta-thinking – very rare, perhaps nonexistent, in animals – is one piece of the story, although perhaps not the only one, of what differentiates our consciousness from other animals.

Pages 154 – 155: Godfrey-Smith presents an interesting aspect of human communication: our communication with ourselves through time via diaries, post-it notes, etc: I had independently thought about the ways in which hyperbolic discounting and schema combine to make us so rather unempathetic for our future selves as to be, in some senses, entirely different people when it comes to agencymemory/etc – and it makes sense that we’d occasionally want to bridge that gap using external influencers of perception and memory that we create.

Pages 160 – 161: an interesting twist in the story that I wasn’t expecting: given the “ compounding” benefits of higher intelligence and memory, you would expect octopi to live a reasonably long time (to reap the benefits of their investment in their brains).  But that’s not the case: they live to only a year or two old, even in the absence of predation.

Pages 162 – 164: Godfrey-Smith asks a fundamental question: why do we age?

Pages 164 – 169: He doesn’t answer this in the standard sense of telomeres, DNA replication, etc, but rather another angle.  There will be far less selection pressure against late-acting mutations that harm us because by the time they pop up, we’ve already likely passed the genes along, especially if they confer some positive bias early on.  (This argument doesn’t apply to organisms, such as trees, that reproduce late in life – in fact, in some instances,greater quantities than young trees.)  See trait adaptivity.

Pages 170 – 175: There’s also the difference between being semelparous (one “big bang” reproduction, like Charlotte’s Web) vs. iteroparous (like humans or dogs).  Godfrey-Smith notes that neither is necessarily better than the other; rather, it’s a case of trait adaptivity and  opportunity costs:

“much depends, again, on the risk of death by predation and other external causes […] suppose in some animal the juvenile stage is risky, but once you get to be an adult, you can expect to live for a while […] then it makes sense for adults to reproduce more than once.  […] if, on the other hand, the adult life stage is very risky, it might make more sense to “go for broke.””

In the case of octopi, since they don’t have shells and – since they are predators that must go out to hunt – at some point, they will be eaten, and it makes sense for them to take the “big bang” approach.

Pages 187 – 189: On where Octopolis came from.  A good example of feedback effects.

Pages 196 – 197: on convergence: intelligence evolved three separate times: in vertebrates, in cuttlefish/squid, and in octopi.

Pages 201 – 202: on overfishing.  Kurlansky’s “COD: A Biography of the Fish that Changed the World” is a good, brief read here.


First Read: early 2018

Last Read: early 2018

Number of Times Read: 1


Review Date: early 2018

Notes Date: early 2018