# Being You **Covers**:: **Source**:: [[Being You by Anil Seth]] **Creator**:: [[Anil Seth]] # Highlights ### PROLOGUE ##### ^308153746 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=71 ###### ^308153746q anesthesia doesn’t just work on your brain, or on your mind. It works on your consciousness. By altering the delicate electrochemical balance within the neural circuitry inside your head, the basic ground state of what it is to “be” is—temporarily—abolished. ^308153746 ##### ^308153747 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=76 ###### ^308153747q Why do we experience life in the first person? ^308153747 ##### ^308153754 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=93 ###### ^308153754q I can replace your brain with a machine that is its equal in every way, so that from the outside, nobody could tell the difference. This new machine has many advantages—it is immune to decay, and perhaps it will allow you to live forever. But there’s a catch. Since even future-me is not sure how real brains give rise to consciousness, I can’t guarantee that you will have any conscious experiences at all, ... since your machine-brain leads to identical behavior in every way, when I ask new-you whether you are conscious, new-you will say yes. But what if, despite this answer, life—for you—is no longer in the first person? ^308153754 ##### ^308153750 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=107 ###### ^308153750q you exist, but the notion that there is a single unique conscious self (a soul?) that persists over time may be grossly mistaken. Indeed, one of the most compelling aspects of the mystery of consciousness is the nature of self. Is consciousness possible without self-consciousness, and if so, would it still matter so much? ^308153750 ##### ^308153751 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=129 ###### ^308153751q a science of consciousness should explain how the various properties of consciousness depend on, and relate to, the operations of the neuronal wetware inside our heads. ^308153751 ##### ^308153752 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=134 ###### ^308153752q I use the word “wetware” to underline that brains are not computers made of meat. They are chemical machines as much as they are electrical networks. ^308153752 ##### ^308344258 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=144 ###### ^308344258q The essence of selfhood is neither a rational mind nor an immaterial soul. It is a deeply embodied biological process, a process that underpins the simple feeling of being alive that is the basis for all our experiences of self, indeed for any conscious experience at all. ^308344258 ##### ^308344259 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=151 ###### ^308344259q our conscious experiences of the world and the self are forms of brain-based prediction—“controlled hallucinations”—that arise with, through, and because of our living bodies. ^308344259 ##### ^314506799 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=161 ###### ^314506799q While he may have been off target in the details, Freud was absolutely right to point out that a naturalistic explanation of mind and consciousness would be a further, and perhaps final, dethronement of humankind. ^314506799 ##### ^314506800 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=167 ###### ^314506800q The novelist Julian Barnes, in his meditation on mortality, puts it perfectly. When the end of consciousness comes, there is nothing—really nothing—to be frightened of. ^314506800 ### I LEVEL #### 1 THE REAL PROBLEM ##### ^314517219 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=184 ###### ^314517219q phenomenology: the subjective properties of conscious experience, such as why a visual experience has the form, structure, and qualities that it does, as compared to the subjective properties of an emotional experience, or of an olfactory experience. ^314517219 ##### ^314517220 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=187 ###### ^314517220q “qualia”: the redness of red, the pang of jealousy, the sharp pain or dull throb of a toothache. ^314517220 ##### ^314517221 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=189 ###### ^314517221q Any kind of experience—any phenomenological property—counts as much as any other. Wherever there is experience, there is phenomenology; and wherever there is phenomenology, there is consciousness. ^314517221 ##### ^314517222 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=190 ###### ^314517222q A creature that comes into being only for a moment will be conscious just as long as there is something it is like to be it, even if all that’s happening is a fleeting feeling of pain or pleasure. ^314517222 ##### ^314517223 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=196 ###### ^314517223q At various times in the past, being conscious has been confused with having language, being intelligent, or exhibiting behavior of a particular kind. But consciousness does not depend on outward behavior, as is clear during dreaming and for people suffering states of total bodily paralysis. ^314517223 ##### ^314517229 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=201 ###### ^314517229q “global workspace” ... mental content (perceptions, thoughts, emotions, and so on) becomes conscious when it gains access to a “workspace,” which—anatomically speaking—is distributed across the frontal and parietal regions of the cortex. ... When mental content is broadcast within this cortical workspace, we are conscious of it, and it can be used to guide behavior in much more flexible ways than is the case for unconscious perception. ^314517229 ##### ^314517227 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=210 ###### ^314517227q “higher-order thought” theory, proposes that mental content becomes conscious when there is a “higher-level” cognitive process that is somehow oriented toward it, rendering it conscious. In this theory, consciousness is closely tied to processes like metacognition—meaning “cognition about cognition”—which again emphasizes functional properties over phenomenology ^314517227 ##### ^314685801 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=218 ###### ^314685801q When a complex phenomenon is incompletely understood, prematurely precise definitions can be constraining and even misleading. ^314685801 ##### ^314685831 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=225 ###### ^314685831q How do conscious experiences relate to the biophysical machinery inside our brains and our bodies? ... The classic formulation of this question is known as the “hard problem” of consciousness. This expression was coined by the Australian philosopher David Chalmers in the early 1990s ... “[E]ven when we have explained the performance of all the functions in the vicinity of experience—perceptual discrimination, categorization, internal access, verbal report—there may still remain a further unanswered question: Why is the performance of these functions accompanied by experience?” ^314685831 ##### ^314685805 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=253 ###### ^314685805q physicalism. This is the idea that the universe is made of physical stuff, and that conscious states are either identical to, or somehow emerge from, particular arrangements of this physical stuff. ^314685805 ##### ^314685806 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=256 ###### ^314685806q idealism. This is the idea—often associated with the eighteenth-century bishop George Berkeley—that consciousness or mind is the ultimate source of reality, not physical stuff or matter. ^314685806 ##### ^314685807 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=258 ###### ^314685807q dualists like Descartes believe that consciousness (mind) and physical matter are separate substances or modes of existence, raising the tricky problem of how they ever interact. ^314685807 ##### ^314685808 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=265 ###### ^314685808q Functionalism is the idea that consciousness does not depend on what a system is made of (its physical constitution), but only on what the system does, on the functions it performs, on how it transforms inputs into outputs. The intuition driving functionalism is that mind and consciousness are forms of information processing which can be implemented by brains, but for which biological brains are not strictly necessary. ^314685808 ##### ^314685809 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=286 ###### ^314685809q Panpsychism is the idea that consciousness is a fundamental property of the universe, alongside other fundamental properties such as mass/energy and charge; that it is present to some degree everywhere and in everything. ^314685809 ##### ^314685810 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=293 ###### ^314685810q mysterianism, which is associated with the philosopher Colin McGinn. Mysterianism is the idea that there may exist a complete physical explanation of consciousness—a full solution to Chalmers’s hard problem—but that we humans just aren’t clever enough, and never will be clever enough, to discover this solution, or even to recognize a solution if it were presented to us by super-smart aliens. ^314685810 ##### ^314685811 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=317 ###### ^314685811q A philosophical zombie is a creature that is indistinguishable from a conscious creature, but which lacks consciousness. A zombie Anil Seth would look like me, act like me, walk like me, and talk like me, but there would be nothing it is like to be it, no inner universe, no felt experience. Ask zombie Anil if he is conscious, and he will say, “Yes, I’m conscious.” Zombie Anil would even have written various essays on the neuroscience of consciousness, including some thoughts about the questionable relevance of philosophical zombies to this topic. ^314685811 ##### ^314685812 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=322 ###### ^314685812q If you can imagine a zombie, this means you can conceive of a world that is indistinguishable from our world, but in which no consciousness is happening. And if you can conceive of such a world, then consciousness cannot be a physical phenomenon. ^314685812 ##### ^314685813 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=324 ###### ^314685813q The zombie argument, like many thought experiments that take aim at physicalism, is a conceivability argument, and conceivability arguments are intrinsically weak. Like many such arguments, it has a plausibility that is inversely related to the amount of knowledge one has. ^314685813 ##### ^314685814 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=337 ###### ^314685814q Whether something is conceivable or not is often a psychological observation about the person doing the conceiving, not an insight into the nature of reality. ^314685814 ##### ^314685832 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=344 ###### ^314685832q According to the real problem, the primary goals of consciousness science are to explain, predict, and control the phenomenological properties of conscious experience. ... the real problem requires explaining why a particular pattern of brain activity—or other physical process—maps to a particular kind of conscious experience, not merely establishing that it does. ^314685832 ##### ^314685817 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=393 ###### ^314685817q a neural correlate of consciousness, or NCC, is “the minimal neuronal mechanisms jointly sufficient for any one specific conscious percept.” ^314685817 ##### ^314685833 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=403 ###### ^314685833q In binocular rivalry, a different image is shown to each eye—perhaps a picture of a face to the left eye and a picture of a house to the right eye. In this situation, conscious perception doesn’t settle on a weird face-house chimera. It flips back and forth between the face and the house, dwelling for a few seconds on each. ... conscious perception changes even though the sensory input remains constant. By looking at what happens in the brain, it’s therefore possible to distinguish brain activity that tracks conscious perception from activity that tracks whatever the sensory input happens to be. The brain activity that goes along with the conscious perception identifies the NCC for that perception. ^314685833 ##### ^314685820 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=412 ###### ^314685820q In the case of binocular rivalry, brain activity that goes along with the conscious perception may also track upstream (prerequisite) processes like “paying attention” and, on the downstream side, the verbal behavior of “reporting”—of saying that you see a house or a face. ^314685820 ##### ^314685821 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=435 ###### ^314685821q Vitalists thought that the property of being alive could be explained only by appealing to some special sauce: a spark of life, an élan vital. ^314685821 ##### ^314685822 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=439 ###### ^314685822q The fatal flaw of vitalism was to interpret a failure of imagination as an insight into necessity. This is the same flaw that lies at the heart of the zombie argument. ^314685822 ##### ^314685823 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=453 ###### ^314685823q the parallel between life and consciousness is not perfect. Most conspicuously, the properties of life are objectively describable, whereas the explanatory targets of consciousness science are subjective—they exist only in the first person. ^314685823 ##### ^314685824 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=461 ###### ^314685824q Conscious level concerns “how conscious we are”—on a scale from complete absence of any conscious experience at all, as in coma or brain death, all the way to vivid states of awareness that accompany normal waking life. ^314685824 ##### ^314685825 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=463 ###### ^314685825q Conscious content is about what we are conscious of—the sights, sounds, smells, emotions, moods, thoughts, and beliefs that make up our inner universe. Conscious contents are all varieties of perception—brain-based interpretations of sensory signals that collectively make up our conscious experiences. ^314685825 ##### ^314685826 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=467 ###### ^314685826q The experience of “being a self” is a subset of conscious contents, encompassing experiences of having a particular body, a first-person perspective, a set of unique memories, as well as experiences of moods, emotions, and “free will.” ^314685826 ##### ^314685827 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=470 ###### ^314685827q it can be tempting to confuse self-consciousness (the experience of being a self) with consciousness itself (the presence of any kind of subjective experience, of any phenomenology, whatsoever). ^314685827 #### 2 MEASURING CONSCIOUSNESS ##### ^314793664 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=502 ###### ^314793664q In thermodynamics, temperature is a large-scale property of the movement of the molecules within a substance; specifically, the mean molecular kinetic energy. ^314793664 ##### ^314793665 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=533 Interesting that we let medical equipment liek this be onfuscated by patents ###### ^314793665q brain-based consciousness monitors have been deployed in operating theaters for many years already. The most common is the “bispectral index” monitor. While the details lie hidden beneath patents, the basic concept is to combine a range of electroencephalographic (EEG) measures together into a single continuously updated number, to guide the anesthesiologist during surgery. This is a fine idea, but bispectral index monitors have remained controversial, partly because there have been several instances where their readings have been inconsistent with other behavioral signs of consciousness, such as patients opening their eyes or remembering what the surgeons had been saying during an operation. A deeper problem, when it comes to consciousness science, is that the bispectral index is not based on any principled theory. ^314793665 ##### ^314793666 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=544 ###### ^314793666q consciousness (awareness) and wakefulness (arousal) can come apart in various ways, which is enough to show that they cannot depend on the same underlying biology. ^314793666 ##### ^314793667 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=560 ###### ^314793667q Consciousness instead seems to depend on how different parts of the brain speak to each other. And not the brain as a whole: the activity patterns that matter seem to be those within the thalamocortical system—the combination of the cerebral cortex and the thalamus ^314793667 ##### ^314793668 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=570 ###### ^314793668q A TMS rig is a precisely controlled electromagnet which allows a researcher to inject a short and sharp pulse of energy directly into the brain through the skull, while EEG in this case is used to record the brain’s response to this zapping. It’s like banging on the brain with an electrical hammer and listening to the echo. ^314793668 ##### ^314793669 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=578 ###### ^314793669q Even though we do not directly feel the TMS pulses, Massimini and Tononi found that their electrical echoes could be used to distinguish different levels of consciousness. In unconscious states, like dreamless sleep and general anesthesia, these echoes are very simple. There is a strong initial response in the part of the brain that was zapped, but this response dies away quickly, like the ripples caused by throwing a stone into still water. But during conscious states, the response is very different: a typical echo ranges widely over the cortical surface, disappearing and reappearing in complex patterns. ^314793669 ##### ^314793670 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=593 ###### ^314793670q The “zip” algorithm—which calculates what’s called “Lempel-Ziv-Welch complexity,” or “LZW complexity” for short—is a popular way of estimating the algorithmic complexity for any given sequence. ^314793670 ##### ^314793671 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=608 ###### ^314793671q the complexity of spontaneous cortical activity—as measured by EEG—reliably drops in both early sleep and anesthesia. We also found that complexity during rapid eye movement (REM) sleep is much the same as during normal conscious wakefulness, which makes sense because REM sleep is when dreaming is most likely—and dreams are conscious. ^314793671 ##### ^314793672 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=621 ###### ^314793672q When a patient can obey a two-part request and clearly state their name and the date, we infer full consciousness. The problem with this approach is that some patients may still possess an inner life but be unable to express it outwardly. ^314793672 ##### ^314793673 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=624 ###### ^314793673q “locked-in syndrome,” where consciousness is fully present despite total paralysis of the body. ^314793673 ##### ^314793674 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=626 ###### ^314793674q Thanks to a quirk of anatomy, locked-in patients may still retain the ability to make limited eye movements, opening a narrow and easily missed behavioral channel for diagnosis and communication. A former editor of Elle magazine—Jean-Dominique Bauby, who became locked-in in 1995 following a brain hemorrhage—wrote an entire book this way, The Diving Bell and the Butterfly. ^314793674 ##### ^314793675 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=632 ###### ^314793675q In Massimini’s 2013 study, locked-in patients had PCI values indistinguishable from healthy age-matched controls—indicating fully intact consciousness. ^314793675 ##### ^314793676 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=663 ###### ^314793676q a recent analysis suggesting that between 10 and 20 percent of vegetative state patients might retain some form of covert consciousness, a number which would translate into many thousands across the world. ^314793676 ##### ^314793677 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=688 ###### ^314793677q Dreaming may be “more conscious” in some ways (for example, the vividness of perceptual phenomenology) but “less conscious” in others (for example, the degree of reflective insight into what is happening). ^314793677 ##### ^314793678 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=695 ###### ^314793678q psychedelic drugs offer unique opportunities for consciousness science since they induce profound alterations in conscious contents, arising from a simple pharmacological intervention in the brain. ^314793678 ##### ^314793679 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=706 ###### ^314793679q In the psychedelic state, vivid perceptual hallucinations are frequently accompanied by unusual experiences of selfhood often described as “ego dissolution,” where the boundaries between self and world, and other people, appear to shift or dissolve. These departures from “normal” conscious experience are so pervasive that the psychedelic state might represent not only a change in conscious contents, but also a change in overall conscious level. ^314793679 ##### ^314793680 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=718 ###### ^314793680q the classic psychedelics—LSD, psilocybin, mescaline, and dimethyltryptamine (DMT, the active ingredient in the South American hallucinogenic brew called ayahuasca)—work primarily by affecting the brain’s serotonin system. ^314793680 ##### ^314793681 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=721 ###### ^314793681q Psychedelic drugs influence the serotonin system by binding strongly to a specific serotonin receptor, the 5-HT2A receptor, which is found throughout much of the brain. ^314793681 ##### ^314793682 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=724 ###### ^314793682q psychedelic state involves striking alterations in brain dynamics, when compared to a placebo control condition. Networks of brain regions that are usually coordinated in their activity—so-called “resting-state networks”—become uncoupled, and other regions that are usually more or less independent become linked. ^314793682 ##### ^314793683 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=733 ###### ^314793683q While high doses of ketamine act as an anesthetic, low doses have more of a hallucinogenic effect.) ^314793683 ##### ^314793684 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=735 ###### ^314793684q Michael Schartner and Adam Barrett calculated the changes in the algorithmic complexity of the MEG signal across many different regions in the brain for all three psychedelic states. The results were clear and surprising: psilocybin, LSD, and ketamine all led to increases when compared to a placebo control. ^314793684 ##### ^314793685 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=749 Bold ###### ^314793685q A brain with all its neurons firing willy-nilly would seem more likely to give rise to no conscious experience at all, just as free-form jazz at some point stops being music. ^314793685 ##### ^314793686 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=751 ###### ^314793686q Intuitively, complexity is not the same as randomness. A more satisfying notion of complexity is as the middle ground between order and disorder—not the extreme point of disorder. ^314793686 ##### ^314793687 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=761 ###### ^314793687q all conscious experiences—are both informative and integrated. ^314793687 ##### ^314793693 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=766 ###### ^314793693q Conscious experiences are informative because every conscious experience is different from every other conscious experience ... At any one time, we have precisely one conscious experience out of vastly many possible conscious experiences. Every conscious experience therefore delivers a massive reduction of uncertainty, since this experience is being had, and not that experience, or that experience, and so on. And reduction of uncertainty is—mathematically—what is meant by “information.” ^314793693 ##### ^315023026 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=776 ###### ^315023026q Each experience reduces uncertainty with respect to the range of possible experiences by the same amount. In this view, the “what-it-is-like-ness” of any specific conscious experience is defined not so much by what it is, but by all the unrealized but possible things that it is not. An experience of pure redness is the way that it is, not because of any intrinsic property of “redness,” but because red is not blue, green, or any other color, or any smell, or a thought or a feeling of regret or indeed any other form of mental content whatsoever. ^315023026 ##### ^315023027 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=782 ###### ^315023027q what is meant by consciousness being “integrated” is still much debated, but essentially it means that every conscious experience appears as a unified scene. We do not experience colors separately from their shapes, nor objects independently of their background. ^315023027 ##### ^315023028 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=804 ###### ^315023028q In a maximally information-rich brain, all neurons would behave independently, firing randomly as if they were completely disconnected. In such a brain, measures of algorithmic complexity, like LZW complexity, would score very high. But this brain—with lots of information but no integration—would not support any conscious states. At the other extreme, a maximally ordered brain would have all neurons doing exactly the same thing, perhaps firing in lockstep together, somewhat like what happens during global epileptic seizures. Algorithmic complexity here would be very low. This brain would also lack consciousness, but for a different reason: lots of integration, no information. ^315023028 ##### ^315023029 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=817 ###### ^315023029q The PCI measure depends on brain activity being integrated in a rather vague way—otherwise, there would be no echo—but it doesn’t measure integration in the same quantitative fashion by which information is measured. ^315023029 #### 3 PHI ##### ^315023038 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=854 ###### ^315023038q “integrated information theory” of consciousness—or IIT. ... IIT says that subjective experience is a property of patterns of cause and effect, that information is as real as mass or energy, and that even atoms may be a little bit conscious. ... According to IIT, consciousness simply is integrated information. ^315023038 ##### ^318150520 highlight_tags:: [[blue]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=870 ###### ^318150520q For me, the bigger problem is that IIT’s extraordinary claims require extraordinary evidence, yet it is precisely the ambition of IIT—to solve the hard problem—that renders its most distinctive claims untestable in practice. The extraordinary evidence that is needed cannot be obtained. ^318150520 ##### ^318150521 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=879 ###### ^318150521q The easiest way to think about Φ is that it measures how much a system is “more than the sum” of its parts, in terms of information. ^318150521 ##### ^315023039 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=881 ###### ^315023039q In IIT, Φ measures the amount of information a system generates “as a whole,” over and above the amount of information generated by its parts independently. This underpins the main claim of the theory, which is that a system is conscious to the extent that its whole generates more information than its parts. ... the level of Φ is intrinsic to a system (meaning that it does not depend on an external observer), and it is identical to the amount of consciousness associated with that system. High Φ, lots of consciousness. Zero Φ, no consciousness. ^315023039 ##### ^318150522 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=890 ###### ^318150522q Imagine a network of simplified artificial “neurons,” each of which can be “on” or “off.” To have high Φ, the network has to satisfy two main conditions. First, the global state of the network—the network “as a whole”—has to rule out a large number of alternative possible global states. This is information, and it reflects the observation from phenomenology that every conscious experience rules out a great many alternative possible conscious experiences. Second, there must be more information when considering the system as a whole than when dividing it into its parts (its individual neurons, or groups of neurons) and considering all the parts separately. This is integration, and it reflects the observation that all conscious experiences are unified, that they are experienced “all of a piece.” Φ is a way of putting a number to a system that measures how high it scores on both these dimensions. ^318150522 ##### ^318150523 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=899 ###### ^318150523q Whatever state it is in (one or zero, on or off) only ever rules out one alternative (zero or one). A single photodiode conveys at most one “bit” of information. ^318150523 ##### ^318150524 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=926 ###### ^318150524q Axioms, in logic, are statements that are self-evidently true, in the sense that they are generally agreed to require no additional justification. “Two shapes that fill exactly the same space are the same shape”—from the Greek philosopher Euclid—is a good example. ^318150524 ##### ^321870750 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=936 ###### ^321870750q Observer-relative (or extrinsic) information is the degree to which uncertainty is reduced, from the perspective of an observer, by observing a system in a particular state. ^321870750 ##### ^314517228 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=6456 ###### ^314517228q Each hemisphere of the cerebral cortex has four lobes. The frontal lobes are at the front. The parietal lobes are toward the back and off to the sides. The occipital lobes are at the back, and the temporal lobes are at the sides, near the ears. Some people identify a fifth lobe—the limbic lobe—deep inside the brain. ^314517228 ##### ^314685829 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=6467 ###### ^314685829q The visual cortex is in the occipital lobe, at the back of the brain. ^314685829 ##### ^314685830 highlight_tags:: [[orange]] Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=6469 ###### ^314685830q Functional MRI (fMRI) measures a metabolic signal (blood oxygenation) related to neural activity—it offers high spatial detail but is only indirectly related to what neurons do. EEG measures the tiny electrical signals generated by the activity of large populations of neurons near the cortical surface. This method tracks brain activity more directly than fMRI, but with lower spatial specificity. ^314685830 ##### ^314793691 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=6473 ###### ^314793691q Imagining (and executing) fluent movements activates cortical regions such as the supplementary motor area, while imagining spatial navigation lights up other regions, such as the parahippocampal gyrus. Anatomically, these brain areas are quite distant from each other. Unsurprisingly, both imagery tasks activate regions involved in hearing and in language processing. ^314793691 ##### ^314793692 Goto: https://readwise.io/to_kindle?action=open&asin=B08W2J9WWD&location=6477 ###### ^314793692q Reflective insight is preserved in the rare “lucid dreaming” state, in which dreamers are aware that they are dreaming and can voluntarily direct their behavior. In a remarkable recent study, researchers were able to communicate with people during lucid dreams by using their eye movements as a channel, much like the locked-in patients described earlier. These dreamers were able to correctly answer simple math problems, as well as various yes/no questions. ^314793692