Consciousness, ego and the microbiome, per Michael Pollan

Nobody yet knows how a handful of neurons produces the experience of being alive. Writer Michael Pollan, author of books including "How to Change Your Mind" and "The Omnivore's Dilemma," spent years researching consciousness for his latest book and arrived at an uncomfortable conclusion: science has no real idea how brain matter generates subjective experience, if it even does. In a conversation with Stanford neuroscientist Andrew Huberman, Pollan explains why that uncertainty is not cause for alarm, but an invitation to look at the brain, the body and even plants differently.

What consciousness actually is

The simplest definition is subjective experience: a toaster does not have it, but a bat probably does, even if we will never know exactly what it is like to navigate the world through sonar. Pollan draws a line between sentience, a basic capacity to detect changes in the environment that may exist even in plants and bacteria, and consciousness, the more elaborate version that includes self-reflection and metacognition. A plant can react to the sound of a caterpillar chewing a leaf and send toxins to defend itself, but that does not mean it knows it is responding. Whether there is "something it is like" to be that plant, that bacterium or that bat is, for Pollan, the line separating a simple reaction from conscious experience.

The ego can switch off, and that is not a bad thing

One of the most studied effects of high-dose psychedelics is ego dissolution: the complete loss of a sense of self. Pollan describes his own experience on psilocybin, in which he watched himself explode into a cloud of blue Post-it notes that then coalesced into paint, with no distress at all, only total equanimity. Berkeley researcher Dacher Keltner demonstrated something similar with a far simpler method: he asked people to draw a stick figure of themselves, gave them an experience of awe such as river rafting, and had them draw the figure again. The second drawing was roughly a third smaller. The ego can be temporarily diluted through meditation, awe or psychedelics, and that dissolution, Pollan says, leaves people with a lighter perspective on their own defensive reactions afterward.

The body feels before the brain thinks

For decades it was assumed consciousness was a cortical phenomenon, something exclusive to complex brains. But a line of research starting with neuroscientist Antonio Damasio and continuing with Mark Solms argues consciousness begins with sensations registered in the brainstem, not with thoughts in the cortex. Hunger, cold and itch are homeostatic signals the body sends to the brain, and only afterward does the cortex step in to imagine a meal or plan how to get one. The strongest evidence comes from children born without a cerebral cortex who, despite that, still show behavioral signs of conscious experience, including pain. If this theory holds, far more species than previously assumed would have some degree of consciousness, since almost all of them share a brainstem.

The microbiome has a vote too

Another idea running through the conversation is how much the body, not just the brain, drives behavior. Gut microbes manufacture neurotransmitters like glutamate, GABA and serotonin, along with short-chain fatty acids that fuel the brain and regulate mood. Pollan cites Stanford microbiologist Justin Sonnenburg, who argues that interactions as simple as shaking hands or sharing a meal serve, from the microbes' perspective, to spread them between people. The relationship runs both ways: humans have outsourced the manufacturing of anxiety-regulating chemicals to bacteria in exchange for offering them a home and transportation.

A caffeine experiment that revealed more than expected

To understand his own relationship with substances, Pollan quit caffeine for three months at the suggestion of psychopharmacologist Roland Griffiths, a pioneer of psilocybin research at Johns Hopkins. The first days were rough: flu-like symptoms, an inability to focus and the sense of not feeling like himself, even after withdrawal symptoms faded. When he drank coffee again, he describes the experience as more powerful than any psychedelic trip he had ever had. Caffeine, consumed daily by 90% of the world's adults, carries real benefits up to about seven or eight cups a day, including mood, blood pressure and cognitive performance, though it also creates a genuine dependence that most people never question.

What the conversation leaves us with

Consciousness remains, in Pollan's words, a problem humanity is "completely stuck" on. But admitting that uncertainty opens the door to taking previously dismissed ideas seriously: that bodily feeling may precede thought, that a silent microbiome shapes decisions we assume are entirely our own, and that temporarily losing the sense of self, whether through meditation or a guided psychedelic experience, can durably change how a person relates to themselves. You do not need to solve the hard problem of consciousness to start paying closer attention to the signals your body sends every day.