What is human consciousness?

Consciousness is “under siege.”

Suddenly lightning-fast computing seems to recreate tasks we commonly associate with intelligence. Yet we’re unprepared as a society to define, let alone create and control, something as pervasive as being. Across close to two-dozen scientific theories of why consciousness appears at all, the so-called “hard problem of consciousness,” none has widespread agreement.

We’re behind in part because at the dawn of the Enlightenment, early scientists focused on measurable phenomenon, in part because they believed that leaving the soul to the church would avoid a political backlash. That allowed hundreds of years of scientific flourishing, but left an underdeveloped sense of self.

That’s from A World Appears: A Journey into Consciousness, a 2026 book by author-science journalist Michael Pollan. Across dozens of interviews and an approachable survey of the research landscape, he ably walks the reader through what we know now. Two stages are easier to test than the two later ones, since it requires consciousness to describe consciousness, but to put it simply:

Cognition is processing information, perhaps by instinct
Intelligence is, as William James defined it, “a fixed goal with variable means of achieving it”
Sentience is a precursor to consciousness, or, as Evan Thompson described it, “the feeling of being alive”
Consciousness is a sense of self, of knowing you know

It’s a fun book, I recommend it.

Below I share my notes for future reference.

My notes:

When Nobel laureate Francis Crick (of DNA fame) turned his immense prestige and reductionist mindset toward consciousness, he gave younger scientists—such as his primary collaborator, Christof Koch—the academic “top cover” needed to study subjective experience in the lab
David Chalmers (whose doctoral adviser was Douglas Hofstadder) argued consciousness could not be reduced to science and bet Koch that it wouldn’t be addressed in 25 years (by 2023). In a famous speech, Chalmers said there was the easy problem (how stuff in the brain works) and the hard problem of consciousness (why it creates consciences)
Phillip Goff’s 2019 Galileo’s Error book: Gallileo argued the soul was not to be touched by science in part because he thought that would keep religion off his back (this gave science the ability to advance by focusing on what could be measured, but that has left consciousness outside the traditional realm of science)
In his seminal 1995 paper, Facing Up to the Problem of Consciousness, philosopher David Chalmers argues that the “hard problem” is explaining why physical brain mechanisms are accompanied by any subjective experience at all
Among the theories: Tunoni: “integrated information theory” OR global workspace theory (Bernard Baars)
“Why should neurons organized and exchanging information in any particular way necessarily feel like something?” Koch was asked in Zurich by Volker Henn
William James. The stream of consciousness
“Consciousness is a labyrinth from which there is no exit” (can’t explore it without using it)
Thomas Nagel consciousness is to be “like something,” it is like something to be a bat but not a toaster
Alfred Korzybski: “the map is not the territory”
Sentinence: the ability to register sensations and respond intelligently
Galileo: “the grand book the universe” is written in mathematics
Galileo, Descartes and Locke set a foundation in the west of “bifurcation of nature” (the quantities like size and shape, and the “secondary qualities” like color, taste and sloubd
To Galileo, color became a frequency of light; taste was a kind of molecule
Descartes: res extensa (matter stuff) and res congitans (mind stuff) — only humans had mind stuff which he used to justify his Iive dissections of animals
This bifurcation worked, keeping science and religion divided and the work thrived
Evan Thompson: science’s “blind spot” is neglecting people’s lived experience
“Brains don’t in fact, hold a monopoly on memory, awareness, cognition, agency, and decision-making. So why should we grant them a monopoly on sentience?”
Darwin: plants are upside down, with brains in the roots and sex organs at the top
Sentinence is a precursor to consciousness, or “the feeling of being alive” as Thompson describes it) — consciousness is a sense of self
William James famously defined intelligence as “a fixed goal with variable means of achieving it” — beyond a fixed instinct
Cognition is acquiring and processing Information (computers and thermostats have intelligence and cognition but not sentience of consciousness yet)
Minimal Intelligence Lab
In his 1995 novel The Information, British author Martin Amis conceptualizes “The History of Increasing Humiliation”. This framing functions as a darkly comedic device to explore the human condition, the diminishing status of literary protagonists, and Amis’s own recurring obsession with male inadequacy, envy, and mid-life crisis.
Richard Powers’ fabe The Overstory of fast moving aliens that view us as inert — like we either plants (time lapse photography helps)
Experimented showing plants can be anesthesia and fall asleep — so that means they’re otherwise awake or conscious?
When asked if plants were conscious, Timothy Plowman said: “they can eat light, isn’t that enough?”
Do plants feel pain when we eat them? Mancuso says no, there’s no evolutionary reason for it because they can’t move (feeling pain while being eaten doesn’t help a plant that can’t move survive)
Third-party science can evaluate intelligence, cognition but not consciousness — expansion of science with meditation or psychedelics or something else
Bayesian brain theory
Karl Friston’s “physics of sentience” says to stave off entropy, three things: a membrane (Markov blankets), an ability to gather information and to act on that information.
Friston: all living beings limit surprise (the climb to consciousness, to return to homeostasis ), and inference is how they do it
Levin’s Xenobot
Author: only mortal systems (that can die) have true goals and intentions. “Machines – so far at least – are extensions of human minds, augmenting our senses, inferences, predictions and actions”
Author has a lot of thermostat discussion of intelligence (it has a fixed goal that it seeks to achieve)
Neuropsychologist Mark Solms argues that consciousness is “felt uncertainty”. Grounded in the Free Energy Principle, the theory posits that the brain is an organ of prediction. We are only conscious of things we do not know or cannot predict; expected, automatic, and habitual processes happen entirely unconsciously.
Biopsychism: all life is sentient; panpsychism: all matter is
“I suspect that the problem of consciousness has become a proxy for our own resistance to reductive explanation, which in term must have something to do with our fear of mortality – that final on wished for reduction of all that we are and all that we value in life to mere matter – to ashes or Compost. They called the immaterial half of his dualism, soul, and souls, after all, are indestructible. The hardness of the heart problem has given us a secular version of the immaterial, immortal soul.”
Is consciousness just another information process or like Evan Thompson argues is it tangled with our mortal bodies like metabolism and digestion (evolved for the flesh)
Damasio: the brain didn’t evolve to support the body but the opppsite — feelings down to itching is the origin even if science ignores these base instincts
(((The chief glory of every people arises from its authors- Samuel Johnson))
Mark Solms’ 2021 book, The Hidden Spring: A Journey to the Source of Consciousness, revolutionizes neuroscience by arguing that consciousness and subjective experience do not originate in the cerebral cortex, but in the brainstem. He posits that raw feelings are the very wellspring of consciousness, acting as evolutionary tools for biological homeostasis. Building upon his work with Antonio Damasio, who led him to homeostasis and feelings as the wellspring of consciousness.
Richard Feynman: If you can’t create it you don’t understand it
David Chalmers 2022 book Reality+ explores the simulated world theory (he leads a team to build a conscious AI)

Garland test from ex machina (the “reverse” Turing test, in which given the knowledge that a system is artificial, does a person still think it has personhood?)
2023 Butlin report: “Our analysis suggests that no current AI systems are conscious, but also suggest that there are no obvious barriers to building conscious AI systems”
Anil Seth in 2025 article “ conscious artificial intelligence and biological naturalism” makes the point that Mary Shelley’s Frankenstein was given life and consciousness and it was the ability to feel that caused it to become homicidal
Richard Lewontin: “ the price of metaphor is eternal vigilance” — but the computer metaphor of the brain has become dominant, including the foundation of the Butlin report (thinking is just software on top of a hardware that could be replaced but author thinks this ignored the biological influences: experiences rewire the brain meaning there is no dualism but hardware/software are the same in the brain
Geoffrey Hinton: Mortal computation (rather than how software can outlive hardware)
“What would we owe machines that can suffer?”
2019 paper Damasio “homestasis and soft robotics in the design of feeling machines” (a machine would need vulnerable soft tissue to ever feel vulnerable, the source of feelings
Kafka: the meaning of life is that it ends
Turkle: technology can make us forget what we know about life” (like how emoji stand in for emotion, and chatbots obscure that we know conversation with a person irl involves so many body language
Planes and birds both have wings and fly but birds have feelings
Edmund Husserl’s Lebenswelt (life world), lived biological experience can’t be ignored by mathematical abstractions
Arthur Eddington’s classic “two tables” metaphor from a 1927 speech distinguishes between the solid, permanent, colored table of everyday experience and the scientific table, which quantum physics describes as mostly empty space with sparsely scattered electric charges. Both tables are equally real; ignoring everyday experience for pure abstraction creates the “blind spot” in modern science.
Dr. Rusell Hurlburt: 50 years of randomly sampling people’s thoughts (true empiricist , he resists theory that could taint his data) . He gives his volunteer language: sometimes early thoughts don’t yet have language or even images but can be “unsymbolized thoughts”
William James: “annihilate a mind at any instant…you will find not the bald word in process of utterance but that word suffused with the whole idea”
Christoff Hadjiileva: “spontaneous thought” shows up in the hippocampus fully 4 seconds before a meditator in a fMRI machine registers it — something unconscious is happening (Raymond Chandler: a thought forming on the edge of consciousness). She wants to take unconscious back for science
To gain legitimacy, psychology dropped the unconscious (associated with hypnosis), and psychoanalysts took over
Daniel Gilbert paper “a wandering mind is an unhappy mind” paper has been disputed and should show the opposite
Dopamine gets more studying than (social) serotonin
2015 Margaret Rennix dissertation: Victorian writers avoided stream of consciousness (like Joyce or Wolfe “ordinary mind on an ordinary day”) because that was viewed as madness, it was impprtant to control thought to be a proper person
Infants and newborns are conscious but don’t initially have a self — by 18 months they pass the mirror test of identifying a sticker on themselves
“At age 3-4, children do not consistently develop their own episodic, or autobiographical, memories, but instead follow those commented on by adults, suggesting this is how we learn to selectively hold on to memories. By 4-5, kids are crafting their own senses of self based on these memories — so how they are interpreted and repeated by adults help them develop an early sense of self, their own story that can shape how they go into the world “
Gopnik: Child numinous lantern style self is less focused but likely more accurate to the world than the Spotlight style adult form that is focused on accomplishing goals set by way of old information and a self view — the first is great for exploration
Psychedelics are one way to return to the childlike wonder
Developmental psychologist Alison Gopnik frequently describes children as the “research and development division” of the human species.: “Kids are the species’s way of getting it out of cultural dead ends.”
Anil Seth 2017 TED Talk on how the brain is a prediction machine: predicting the causes of all the stimuli that senses are capturing ; our everyday is a “controlled hallucination”

William James “the perception of bodily changes as they occur is the emotion “ — we tremble first and then call it afraid
“In a famous 1974 experiment, a female interviewer approached men who had crossed one of two bridges over a river in British Columbia. One of the bridges was quite rickety and precari-ous, the other firm and sturdy. After the interview, the woman offered her phone number to each bridge crosser, inviting them to call if they had any follow-up questions. The men who had crossed the rickety bridge were much more likely to call her. Why? Their brains had misattrib-ted the physical arousal caused by crossing a perilous bridge to sexual chemistry rather than fear or anxiety. See Anil Seth, Being You: A New Science of Consciousness (Dutton, 2021), 177.
Michael Levin: caterpillars can be trained to associate red leaves with food, and even after complete brain rewiring that takes place for metamorphosis into a butterfly it will still associate red with foood or pleasure (even though they eat nectar not leaves then) — the self isn’t a thing but a process of sense making (mnemonic improvisation”)
Frank Jackson knowledge argument: book knowledge also requires what philosophers call “quaila”
Ian McGilchrist: the brain is a receiver of consciousness (like a radio tuning to radio waves)
Koan in meditation
Meditation in cave in New Mexico closes the authpr’s view to think of consciousness : “ less, as a scientific or philosophical puzzle to be solved and more as practice, a way to once again be altogether here, present to life into this fault of stars”