Narrator: Imagine discovering an alien intelligence. Not in the distant stars, but right here on Earth, hidden beneath the waves. This isn't science fiction. In 2009, a scuba diver named Matthew Lawrence was exploring a bay in Australia when he stumbled upon something extraordinary: a dense settlement of octopuses, each living in a den made of scallop shells. They were interacting, signaling, and even fighting. This site, later named Octopolis, was like a city, challenging everything we thought we knew about these supposedly solitary creatures. How could an animal with a lineage so radically different from our own—a mollusk, more closely related to a clam than a human—develop such complex behavior?

This encounter with an "other mind" is the central puzzle explored in Peter Godfrey-Smith's book, Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness. The book takes us on a journey 600 million years into the past to find the last common ancestor we shared with the octopus—a simple, worm-like creature—and traces the two separate paths evolution took to create intelligence, forcing us to confront the profound question of what a mind truly is.

Narrator: The most profound insight from the octopus is that it represents a completely independent experiment in the evolution of the mind. While we share a deep evolutionary history with other intelligent animals like chimpanzees, dolphins, and crows, our path diverged from the cephalopod line about 600 million years ago. The last ancestor we shared was a simple, flatworm-like organism with little more than basic light-sensing spots and a primitive nervous system.

From that ancient split, two grand evolutionary journeys unfolded. One branch, the vertebrates, eventually led to us. The other, a line of invertebrates, led to the mollusks, and eventually, to the cephalopods. This means that the large brain, the complex problem-solving abilities, and the curious nature of the octopus were not inherited from a shared, intelligent ancestor. They were built from scratch, a second time. As Godfrey-Smith puts it, if we can make contact with cephalopods as sentient beings, it is not because of kinship, but because evolution built minds twice over. This makes them the closest thing we may ever come to meeting an intelligent alien, offering a unique chance to understand the essential ingredients for a mind.

Narrator: To understand how minds evolved, we must go back to a period of dramatic change: the Cambrian explosion, which began around 542 million years ago. Before this, life was slow and simple. But during the Cambrian, a biological arms race ignited. For the first time, animals began to actively hunt each other. This new dynamic of predation drove the rapid evolution of bodies and senses. Eyes, claws, shells, and mobility became critical for survival.

In this new, dangerous world, the nervous system took on a crucial role. It wasn't just for coordinating internal functions anymore; it became the link between perception and action. An animal needed to see a threat and react instantly, or spot prey and launch an attack. Godfrey-Smith explains that from this point on, the mind evolved in response to other minds. This interaction—this constant game of eat or be eaten, of outsmarting and escaping—is what fueled the development of the complex nervous systems that underpin all animal intelligence today, both in our lineage and in the octopus's.

Narrator: Unlike the centralized command center of the human brain, the octopus nervous system is radically distributed. An octopus has around 500 million neurons—comparable to a small dog—but more than half of them are not in its brain. They are located in its eight, highly flexible arms. Each arm can act with a degree of independence, capable of touching, tasting, and moving on its own. This creates a unique form of embodied cognition, a mind that is not just in the head, but is spread throughout the body.

This decentralized model gives rise to famously "mischievous and crafty" behavior. Laboratory stories abound of octopuses who seem to understand their captive situation. One octopus, observed by researcher Jean Boal, was repeatedly fed boring, thawed-out squid. After one feeding, the octopus held the squid, made eye contact with Boal, slowly crawled over to the tank's outflow drain, and deliberately dumped the food down it. In another case, octopuses in two separate aquariums learned to short-circuit the power by squirting jets of water at the overhead bulbs, seemingly because they disliked the bright light. This isn't just instinct; it's a flexible, problem-solving intelligence that blurs the line between brain and body.

Narrator: What does it actually feel like to be an octopus? This question leads to the philosophical heart of the book: the nature of subjective experience. Godfrey-Smith argues that experience isn't a mysterious add-on that appeared late in evolution. Instead, it arises from the fundamental feedback loop between sensing and acting.

A powerful illustration of this is the Tactile Vision Substitution System, or TVSS, a device developed to help blind people "see." A camera translates visual information into patterns of vibrations on a person's back. At first, users just feel buzzing on their skin. But a crucial change occurs when they are given control over the camera. By moving the camera themselves, their actions directly influence their sensations. This feedback loop transforms the experience. They no longer feel buzzing on their back; they begin to perceive objects out in space. This suggests that subjective experience—the feeling of "what it's like"—is intimately tied to an organism's ability to act on the world and perceive the consequences of those actions.

Narrator: Cephalopods are masters of color and pattern. Their skin is a living screen, packed with millions of pigment sacs called chromatophores that are controlled directly by the brain. They can change color in an instant, producing dazzling displays for camouflage, communication, or startling predators. The author describes personal encounters with giant cuttlefish who seem to have distinct personalities, expressed through their skin—some curious, some hostile, some indifferent, each communicating through a unique symphony of color.

This ability presents a puzzle: cephalopods are thought to be color-blind, possessing only one type of photoreceptor in their eyes. How can they match their background so perfectly without seeing color? Recent research suggests a startling answer: they may see with their skin. Scientists have found that the same light-sensitive proteins found in the octopus eye are also present in its skin. Experiments have shown that a detached piece of octopus skin can still react to light, causing the chromatophores to expand. The skin itself can both sense light and produce a response, a truly alien form of perception.

Narrator: For all their intelligence, most octopuses and cuttlefish live brutally short lives, typically only one or two years. After a single, massive reproductive event, their bodies begin to rapidly decline in a process called senescence. They literally fall apart. This presents an evolutionary puzzle: what is the point of building such a large, complex brain if it's only used for such a short time?

The answer lies in the trade-offs of evolution. When cephalopods lost their protective outer shells, they became both agile predators and vulnerable prey. This high-risk lifestyle favored a "live fast, die young" strategy. Evolution invested in building a complex brain for hunting and camouflage, but because the daily risk of being eaten was so high, there was little evolutionary pressure to maintain the body for a long life. A stunning exception proves the rule: a species of deep-sea octopus, living in a much safer environment with fewer predators, was observed brooding its eggs for over four years. This shows that the octopus body is capable of a long life; it is the pressure of their environment that has tuned their lifespan to be so brief.

Narrator: The discovery of Octopolis turned the idea of the solitary octopus on its head. Here, in a small patch of the seafloor, researchers used unmanned cameras to capture a rich and complex social world. They observed octopuses engaging in elaborate interactions. Males would adopt a threatening "Nosferatu" pose—standing tall, turning dark, and spreading their web like a cloak—to intimidate rivals.

They were seen "boxing" with their arms, which may be a form of recognition or testing. And they used color to signal intent: dark colors reliably predicted an attack, while a pale, blotchy pattern—normally used to startle predators—seemed to be co-opted as a signal of submission. These behaviors suggest that, under the right conditions, octopuses are capable of a level of sociality previously thought impossible. Octopolis is a window into what their minds can do when confronted with the constant presence of other minds.

Narrator: The single most important takeaway from Other Minds is that intelligence is not a single peak with humans at the summit. It is a vast, branching tree, and the octopus represents a completely separate branch that has reached its own kind of cognitive sophistication. Studying the octopus is a lesson in humility; it forces us to abandon our anthropocentric biases and appreciate the sheer diversity of ways a mind can be constructed. Their decentralized nervous system, their skin that can see, and their brilliant but brief lives challenge our most basic assumptions about the relationship between body, mind, and experience.

The book leaves us with a profound final thought. The ocean is the cradle of all life, the place where nervous systems and the first glimmers of experience were born. It is the home of this "other mind" that we are only just beginning to understand. As we continue to explore this alien intelligence, we must also recognize our responsibility to protect its world, a world threatened by overfishing and chemical change. What other minds, what other evolutionary experiments, might we lose before we even have a chance to meet them?