'I feel, therefore I am'

Antonio Damasio explores how the body's signals, feelings and vulnerability shape consciousness - and what this means for artificial intelligence

By David Eagleman Natural Intelligence & the Logic of Consciousness

by Antonio Damasio

Published by Pantheon

240 pages $30

 A language model can describe thirst in a hundred ways without ever thirsting; it can compose a sonnet about hurting without knowing pain. For Antonio Damasio, that gap between representing and feeling is a critical difference between human and artificial intelligence (AI). 

In the intriguing Natural Intelligence & the Logic of Consciousness,he argues that a mind only emerges when a living body gives its internal processes urgency, value and stakes. 

Damasio, a neuroscientist at the University of Southern California, has spent three decades dismantling the idea that reason lives upstairs in the modern penthouse of the cortex, uncontaminated by the body’s plumbing. Descartes’ Error, his first book, posited that patients who lose access to signals from their body are impaired in their ability to make decisions. Natural Intelligence is the most complete realisation of his ethos yet; Damasio’s thesis might be, “I feel, therefore I am.” 

The book’s organising principle breaks up the mind into several interwoven processes. First, there’s the perceptual mind, which paints the outside world in sounds, colour, textures, smells and tastes (this is known as “exteroception,” detecting the outside world). 

Then there’s the “reflective/linguistic” mind — the cortex’s inner theatre of memories, words and planning. 

The part of the mind that Damasio says has been too long underappreciated is the feeling mind, built on interoception, which includes the continuous monitoring of respiration, temperature, heartbeat, blood circulation, blood chemistry, visceral musculature and other internal affairs. 

These three categories, he explains, have different biological foundations, different evolutionary ages and different consequences. But they collaborate. We might think of an integrated mind like a smartphone: Perception and reflection are the flashy, battery-draining apps, while the feeling mind is the unnoticed and massive operating system that keeps the hardware working. 

The feeling mind is the centre of gravity in this book. It evolved to “continuously qualify” everything happening in the rest of the mind, assigning positive, neutral or negative valences. 

To illustrate what is special about the homeostatic functions of the body, Damasio turns to often overlooked details of the neuroanatomy. The nerves carrying sight and sound are thickly myelinated (rather like the insulation on copper wiring), but he notes that the neurons monitoring your body’s interior are mostly bare. 

As a result, chemical signals in the bloodstream wash directly against the nerves, producing not just digital information but qualitative events, such as pain, nausea, hunger and relief. Damasio calls the low-grade hum of this traffic the “feelings of existence”: the ineffable sense of occupying a body, which he suggests is the bedrock of subjective experience.

Consider another metaphor: The visual world and the cortex’s clever thoughts are a film reel, while the feeling body is the projector. Turn off the projector (as anaesthesia does, by chemically separating the brain from the body’s distress signals) and the reel keeps spinning in the dark, with nobody watching. 

To buttress his claims, Damasio turns to clinical studies of coma patients. It’s long been known that damage to a small, specific area of the brainstem can extinguish consciousness entirely. Why? Because that spot is where interoceptive signals (for example, from the heart and lungs) first arrive and get coordinated. 

By contrast, if large stretches of the cortex are destroyed, patients may lose language or memory or sight, but they nonetheless remain consciously present. Damasio uses this startling asymmetry as his rationale for diffusing the seat of the conscious self well beyond the newer parts of the brain (like the cortex) where centuries of thinkers had assumed it lived. 

He also turns his sights on the loudest conversation of the moment: artificial intelligence. He doesn’t dispute that large language models are formidable; he allows that the human brain processes information at a crawl compared with current AI. But speed is beside the point. 

In the author’s view, a system with no metabolism has nothing to protect. This means no stakes, and no stakes means no feeling — and therefore no consciousness. A current large language model can’t be hungry or dying, and therefore has no projector light because it has no vulnerable body to generate one. 

He is, however, willing to imagine future machines endowed with this vulnerability, self-concern and slow analog processes resembling those of the autonomic nervous system. He calls the possibility “enticing” and notes that research along this avenue is only in its infancy. 

To my mind, Damasio’s position succeeds on two levels and becomes slightly more uncertain at a third. He makes a formidable case that human consciousness cannot be understood by studying cortical computation alone. He also supplies a richly detailed account of the bodily and neural machinery from which homeostatic feelings arise. 

The larger assertion, that feeling is the indispensable substrate of consciousness, is harder to establish. At the decisive point, “feeling” risks becoming not an explanation of subjectivity but another name for the thing that needs explaining. Why should this particular traffic between flesh and neuron feel like anything at all? 

Damasio writes that if the traffic between flesh and neuron did not feel — for bad or good — it could not call attention to its presence and possible cause. Agreed. But we could still have a “why” without a full understanding of the “how.” 

Nonetheless, Damasio has shifted the burden of proof. Any theory that tries to explain consciousness while ignoring vulnerability, self-concern and the body’s ceaseless conversation with the brain now looks conspicuously incomplete.

He may not have solved consciousness conclusively, but he has successfully granted the mystery a body and 

a pulse.

 

The reviewer is a neuroscientist at Stanford University and the author of eight books, most recently Livewired ©2026 The New York Times News Service