|
大腦神經學：意識篇 – 開欄文
|
瀏覽4,542 ｜回應23｜推薦1 |
|
|
|
我求知的主要興趣從倫理學轉向認知科學後，偶而會涉及到一些討論「意識」的科普書籍。讀了恰爾莫斯教授的《具有意識的心靈：追求基本理論》一書後，在我(自以為)了解該書意旨範圍內，我對他「經驗本質」概念和「意識研究上的困難議題」說法兩者，都持存疑態度。自然也就使得我在過去20多年中，進一步讀了不少關於「意識」的書籍以及研究報告。我收集了相當多這方面的論文；本部落格在過去曾經轉載了一些。我也試圖系統性寫下自己的觀點；但因為功力不足，寫寫停停一直無法成章。
在倫理學之外，這是我最希望能把過去讀書心得整理出來的一個領域。先轉載我認為有爭議的兩篇文章來起個頭。
本文於 修改第 1 次
|
|
「意識」不需要一個「自我」 - James Cooke
|
|
|
推薦1 |
|
|
|
從下文內容看來，我們可以把庫克博士歸之於：「泛意識論者」，或至少是一位：「生物界內意識無所不在論者」。換句話說，他還不是一位全然胡說八道的人；例如，那些「宇宙內意識無所不在論者」。我沒有能力批判他的觀點或論述；不過，庫克博士顯然搞錯了對象或文法：
「意識」的確不需要「自我」；事實上，「自我」需要「意識」。或者說：「『意識』為『自我』之本」。
索引：
Bayesian inference：
Free energy principle：
Karl Friston：請參見：Karl Friston Website, www.fil.ion.ucl.ac.uk/~karl
Consciousness does not require a self
The self is a prediction of the brain
James Cooke, 12/14/23
The idea that consciousness requires a self has been around since at least Descartes. But problems of infinite regress, neuroscientific studies, and psychedelic experiences point to a different reality. 'You' may not be what you seem to be, writes James Cooke.
We typically feel like we are the conscious subject, the one who has experiences. Look around you in this moment and direct your attention to different objects. It can feel like we exist in our heads, behind our eyes, directing a spotlight of attention in order to wilfully make things conscious. This intuitive model of the mind has often been imported into the science and philosophy of consciousness, leading to confusion in our understanding of the true nature of experience. This subject is not the bodily organism, it is something that is felt to live inside us, the possessor of the body, the “you” that is reading these words now. Consciousness is very much a property of the bodily subject, but not of the conscious subject that is felt to live in our heads.
Thinking in terms of conscious subjects was present at the very origins of the scientific method, in the work of Rene Descartes. Descartes saw the natural world as unconscious mechanism. Humans alone were conceived of as being conscious by virtue of a transcendent subject that could illuminate our experience of the world [1]. If we want to understand consciousness, however, postulating the existence of an inherently conscious subject merely passes the buck of explanation. What makes that conscious subject conscious? If it is intrinsically conscious then consciousness has not been explained. If not, then what makes it conscious, another subject within it? With this logic we end up in an infinite regress, with consciousness never being explained. This view of the mind has been dubbed the Cartesian Theatre by philosopher Daniel Dennett [2].
Many scientific accounts of consciousness too appeal to a self-like mechanism in the brain that is responsible for bestowing the illuminating quality of consciousness on the informational content processed by the brain [3]. The brain is a hierarchically structured network, with sensory information entering the brain at the bottom of this hierarchy and subsequently passing through multiple layers of processing. In contrast to the lower levels which analyse sensory information, the top levels deal with cognitive tasks such as decision making and the directing of attention. Some theories hold consciousness to arise in a bottom-up manner, passively bubbling up out of the information-processing performed by the brain. Subject-based theories, on the other hand, see consciousness as a top-down phenomenon, something that occurs as the result of active introspection performed by high-level brain regions [4]. The brain is organised so that sensory information is predominantly processed in the posterior half of the brain, while executive functions such as decision-making and attention largely rely on brain areas in the front half of the brain. Neural correlates of consciousness have been observed in both posterior and anterior brain regions, lending credence to both the bottom up and top down perspectives [5].
There’s one issue, however, the fact that frontal areas of the brain are recruited by the act of communication. When the subject in an experiment reports what it is that they are consciously perceiving, we cannot tell if the frontal brain activity is due to it playing a role in consciousness itself or merely the act of reporting on the contents of consciousness. One study found a clever way around this, by deciphering what subjects were experiencing based on physiological data, such as pupil dilation. When the subjects didn’t have to report the contents of consciousness, the frontal correlates diminished [6]. The neural structures we associate with the idea of the introspecting subject seem to not underpin consciousness itself after all, but to instead merely report on the contents of consciousness.
Beyond the neuroscientific study of consciousness, phenomenological analysis also reveals the self to not be the possessor of experience. In mystical experiences induced by meditation or psychedelics, individuals typically enter a mode of experience in which the psychological self is absent, yet consciousness remains [7]. While this is not the default state of the mind, the presence of consciousness in the absence of a self shows that consciousness is not dependent on an experiencing subject. What is consciousness if not a capacity of an experiencing subject? Such an experience reveals consciousness to consist of a formless awareness at its core, an empty space in which experience arises, including the experience of being a self [8]. The self does not possess consciousness, consciousness is the experiential space in which the image of a psychological self can appear. This mode of experience can be challenging to conceptualise but is very simple when experienced – it is a state of simple appearances arising without the extra add-on of a psychological self inspecting them.
We can think of a conscious system as a system that is capable of holding beliefs about the qualitative character of the world. We should not think of belief here as referring to complex conceptual beliefs, such as believing that Paris is the capital of France, but as the simple ability to hold that the world is a certain way. You do this when you visually perceive a red apple in front of you, the experience is one of believing the apple to exist with all of its qualities such as roundness and redness. This way of thinking is in line with the work of Immanuel Kant, who argued that we never come to know reality as it is but instead only experience phenomenal representations of reality [9]. We are not conscious of the world as it is, but as we believe it to be.
There is a branch of mathematics that deals with how we optimally update our beliefs in light of new evidence, known as Bayesian inference. One issue with seeing the brain as performing Bayesian inference is that this process involves knowing the probability of all possible causes that could have given rise to any piece of evidence, information the brain could not possibly have access to. A workaround has been found in the strategy of “free energy minimization”, in which the brain starts with a guess about the causes of sensory inputs and updates it in light of how surprising the evidence it receives would be if that belief were true [10]. With this approach, this initial belief is successfully sculpted to align with reality, with no need to know all of the possible causes behind any piece of evidence. This dynamic is described in Karl Friston’s Free Energy Principle (FEP), and it goes a long way to account for how the contents of consciousness are shaped by the sensory inputs the brain receives, as well as by the prior beliefs that it holds [11].
The FEP does not just explain how the beliefs that underlie our perception of the world become shaped, but it also accounts for how it is that we come to act in the world [12]. In this framework, known as active inference, a belief is initially formed about the world being in a state that is different to its current state. Say you are sitting down and want to stand up. The brain creates the belief that you are standing up and then your body moves in whatever way is necessary to reduce the surprising feedback it receives, given that you are not currently in that state. The end result is that you move towards the goal of standing via an optimal trajectory. In his “Beast Machine” theory of selfhood, Anil Seth suggests that the experience of the subject is a Bayesian belief of this kind [13]. The belief in an unchanging self that continues over time becomes a self-fulfilling prophecy as a result of this process of prediction-error minimization, under the active inference framework. We come to act like a coherent bodily self over time because we have the belief that we are a stable unitary self. We perceive ourselves into existence.
If consciousness is thought to depend on complex cognitive machinery that allows for the construction of a psychological self that can introspect, we can flatter ourselves with the impression that only we, and complex creatures sufficiently like us, are conscious. If this is not the case, however, and consciousness is something less complex yet more fundamental than the self, we are faced with the possibility that experience may exist more widely than is commonly thought. By getting rid of the subject, we can see consciousness to not be the product of sophisticated brains that can introspect on experience but instead as the fundamental ability to know the world that all organisms possess.
Belief updating does not just happen in brains, it is a fundamental aspect of being alive. We typically dismiss the possibility of organisms without nervous systems as being conscious because of the widespread belief that they can function by unconscious reflex alone. This idea is a myth that contravenes our understanding of the thermodynamics of life. In order to survive over time, we need to construct beliefs about the world so that we can successfully navigate it. The FEP not only provides a strategy by which brains can perform approximate Bayesian inference, it also shows that such a strategy is necessary for any living system that can keep itself orderly over time [14].
In this view, consciousness does not require a complex brain that can construct a self with the power to make the contents of the mind conscious. Consciousness is instead seen as the attempt to know the world that all living things must engage in, in order to exist over time. In this way, we can see consciousness as existing in the way that the organism interacts with the world, as a process or behaviour rather than as a “thing”. From this perspective, the space of awareness that exists prior to the experience of the self can be conceived of as what Thomas Metzinger has called an “epistemic space”, the space in which beliefs about both the character of the world and the self can arise [15]. By understanding consciousness to exist prior to the experience of psychological selfhood, we can both remove a major roadblock to the scientific understanding of consciousness and come to know the nature of our own minds more fully.
References:
[1] Descartes, R. (2013). Meditations on first philosophy. Broadview Press.
[2] Dennett, D. C., & Kinsbourne, M. (1992). Escape from the Cartesian theater. Behavioral and Brain Sciences, 15(2), 234-247.
[3] Seth, A. K., & Bayne, T. (2022). Theories of consciousness. Nature Reviews Neuroscience, 23(7), 439-452.
[4] Lau, H., & Rosenthal, D. (2011). Empirical support for higher-order theories of conscious awareness. Trends in cognitive sciences, 15(8), 365-373.
[5] Koch, C., Massimini, M., Boly, M., & Tononi, G. (2016). Neural correlates of consciousness: progress and problems. Nature Reviews Neurosciene
[6] Frässle, S., Sommer, J., Jansen, A., Naber, M., & Einhäuser, W. (2014). Binocular rivalry: frontal activity relates to introspection and action but not to perception. Journal of Neuroscience, 34(5), 1738-1747.
[7] Millière, R., Carhart-Harris, R. L., Roseman, L., Trautwein, F. M., & Berkovich-Ohana, A. (2018). Psychedelics, meditation, and self-consciousness. Frontiers in psychology, 9, 1475.
[8] Shear, J., & Jevning, R. (1999). Pure consciousness: Scientific exploration of meditation techniques. Journal of consciousness studies, 6(2-3), 189-210.
[9] Kant, I. (1908). Critique of pure reason. 1781. Modern Classical Philosophers, Cambridge, MA: Houghton Mifflin, 370-456.
[10] Friston, K., Kilner, J., & Harrison, L. (2006). A free energy principle for the brain. Journal of physiology-Paris, 100(1-3), 70-87.
[11] Skora, L. I., Seth, A. K., & Scott, R. B. (2021). Sensorimotor predictions shape reported conscious visual experience in a breaking continuous flash suppression task. Neuroscience of Consciousness, 2021(1), niab003.
[12] Friston, K., Mattout, J., & Kilner, J. (2011). Action understanding and active inference. Biological cybernetics, 104, 137-160.
[13] Seth, A. (2021). Being you: A new science of consciousness. Penguin.
[14] Friston, K. (2013). Life as we know it. Journal of the Royal Society Interface, 10(86), 20130475.
[15] Metzinger, T. (2020). Minimal phenomenal experience: Meditation, tonic alertness, and the phenomenology of “pure” consciousness. Philosophy and the Mind Sciences, 1(I), 1-44.
James Cooke is a neuroscientist, writer & speaker, focusing on consciousness, meditation, psychedelic states, science and spirituality.
Additional Reading：
Post-liberalism and its dangers
Misinformation is the symptom, not the disease
A New Model of Consciousness By Daniel Stoljar
本文於 修改第 2 次
|
|
腦波推動思考和意識的形成 -- Tim McMillan
|
|
|
推薦1 |
|
|
|
下文所報導顯示：彌勒教授的的研究，在增進我們對「意識」的了解上做出巨大貢獻。但宣稱「腦波」推動「思考」和「意識」的形成，則言過其實。
我們都看過許多類似「骨牌效應」但別出心裁的視頻。如果有人截取其中任何一個環節，然後說：這是「推動」整個過程的核心步驟；大概沒幾個人會相信。
「思考」和「意識」是整個大腦結構各部份分工合作複雜過程的結果。「腦波」有其重要甚至決定性的角色無庸置疑。如果說它們是推手，恐怕言之過早。
MIT Neuroscientist Proposes Brain Waves are the Hidden Engine Behind Thought and Consciousness
Tim McMillan, 11/16/25
When it comes to understanding the mystery of human consciousness, scientists have long sought the hidden mechanism that transforms mere neural firing into the rich experience of thought.
Now, a leading MIT neuroscientist believes he’s found a clue that suggests the brain’s electrical waves don’t just reflect our thoughts, but actually create them.
At the Society for Neuroscience’s annual meeting on November 15, Dr. Earl K. Miller, a professor at MIT’s Picower Institute for Learning and Memory, will unveil a provocative proposal: that cognition and consciousness emerge from the fast, flexible organization of the brain’s cortex—powered by analog computations performed by traveling brain waves.
In other words, the rhythm of the brain may be more than background noise—it may be the very pulse of thought itself.
“The brain uses these oscillatory waves to organize itself,” Dr. Miller said in a press statement. “Cognition is large-scale neural self-organization. The brain has got to organize itself to perform complex behaviors. Brain waves are the patterns of excitation and inhibition that organize the brain, and this leads to consciousness because consciousness is this organized knitting together of the cortex.”
Dr. Miller’s theory revives the concept of analog computation. Unlike digital computers, which rely on discrete binary bits, analog systems process continuous information—waves interacting to produce a vast range of possible values.
Dr. Miller argues that the brain’s natural oscillations—electrical waves generated by millions of neurons—function as analog computers, sculpting information in a fast, flexible, and energy-efficient way.
Over three decades of research in Dr. Miller’s lab at MIT have demonstrated how these waves help organize information flow across the cortex—the outermost layer of the brain responsible for higher cognitive functions.
His work suggests that brain waves act like traffic signals for thought: slower “top-down” frequencies carry goals and rules, while faster waves deliver sensory information. Together, they guide what we perceive, remember, and decide.
In the early 2000s, Dr. Miller co-authored one of neuroscience’s most cited papers, demonstrating that the brain’s prefrontal cortex not only processes information but also actively maintains goal-directed patterns that influence the behavior of other regions.
Later studies revealed that many neurons aren’t tied to one function. Instead, they are “multitaskers,” capable of participating in multiple networks.
But the key question remained: how does the brain coordinate these constantly shifting networks so efficiently?
By 2007, Miller’s team began to find answers in the patterns of neural oscillations. They discovered that alpha and beta waves (about 15–35 Hz) carry top-down control signals—essentially, the brain’s internal rules. Meanwhile, gamma waves (35–60 Hz) carry incoming sensory data.
In cognitive tasks such as working memory, beta waves appear to constrain gamma activity, effectively imposing the brain’s goals on the flood of sensory input.
That interplay, Dr. Miller explains, is what allows the brain to exercise conscious control. When we need to recall something from short-term memory—like remembering the day’s lunch specials—the brain temporarily reduces the strength of slower beta waves, allowing faster gamma waves to retrieve the stored information.
In essence, the balance between these wave patterns determines when certain thoughts emerge and when they remain suppressed.
Recent studies have extended these findings across the entire cortex. A 2020 paper from Dr. Miller’s lab showed that wave frequencies increase gradually from the back of the brain to the front, creating a continuous gradient of rhythm.
In another study, his team demonstrated that this same pattern exists across species—from monkeys to humans—with deeper cortical layers producing slower beta waves and surface layers generating faster gamma waves.
This discovery hinted at a deeper organizational principle: that the cortex operates as a coordinated, wave-based computing system.
In 2023, Dr. Miller and his colleagues formalized this idea in what they call the “Spatial Computing” theory of cognition. The model proposes that brain waves sculpt temporary neural networks by acting like stencils: slower beta waves set the constraints, while faster gamma waves fill in the details.
When the brain’s goals demand certain information, beta waves permit gamma waves to activate the right cortical “patch,” allowing quick, targeted retrieval without rewiring the brain’s physical connections.
That’s key, Dr. Miller argues, because synaptic rewiring—the process by which neurons physically strengthen or weaken their links—is too slow for real-time cognition. Waves, by contrast, can sweep across the brain at lightning speed, providing the flexibility and coordination necessary for thought.
For Dr. Miller, consciousness isn’t a separate process from thought—it’s its highest expression. “Consciousness is the tip of the iceberg of cognition,” he says.
Most of the brain’s wave-driven computations happen automatically. Yet consciousness provides a layer of oversight, allowing us to pause, plan, or override instinct.
“Consciousness is there for planning behavior before you engage in it, and for countermanding ongoing decisions that are going to be stupid,” Dr. Miller says. “In that second mode, it’s almost as if consciousness is the story your brain makes up to explain what it just did… It’s there to keep tabs on itself and plan the future.”
That dual function—monitoring and control—could explain why consciousness feels both immediate and reflective, both active and observing. It’s the brain keeping score of its own activity, organizing the symphony of waves into coherent experience.
Dr. Miller’s collaboration with anesthesiologist and MIT colleague Emery N. Brown has provided further evidence for his theory. Studying the effects of general anesthesia—essentially the “off switch” for consciousness—his team has shown that anesthetic drugs disrupt the normal balance of beta and gamma waves.
Under anesthesia, the cortex’s wave coordination breaks down. Communication between sensory and higher-order regions falters, and the rhythmic traveling waves that normally synchronize thought become disorganized or phase-shifted. Different anesthetic agents even push the brain’s wave frequencies out of alignment, impairing their ability to perform analog computations.
In short, when the music of the brain stops, so does the mind.
Dr. Miller’s proposal remains unproven. However, it could have profound implications for how neuroscientists think about the brain and cognition. His analog-computation framework ties together decades of experimental results under a unifying concept that consciousness may not emerge despite the brain’s noisy rhythms, but because of them.
By presenting his theory, Dr. Miller hopes to spark deeper exploration into how the cortex’s self-organizing waves give rise to intelligence—and perhaps even to the sense of self itself.
Ultimately, if the idea holds, the secret of human thought may lie not in the static wiring of the brain, but in its ever-shifting patterns of energy—an elegant analog dance of waves that never stops moving, yet somehow gives rise to awareness.
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com
See Also
Sandstorms on an Alien World Are Revealed in New Data Collected by the James Webb Space Telescope
本文於 修改第 1 次
|
|
意識迷團 -- Tanner on Truth & Myths
|
|
|
推薦1 |
|
|
|
7 Things About Consciousness Science Still Can’t Explain
You’re made of meat. But somehow, you think. You feel. You dream. And science? Still scratching its head.
Tanner on Truth & Myths, 01/16/26
You woke up this morning and knew you were you. Not a toaster. Not a tree. You’re in your body, behind your eyes, watching the world unfold like some ghost in a meat machine. You can think about thinking. You can imagine impossible things. You can remember, regret, fantasize, and scream into the void.
And yet — ask the smartest scientist alive to explain why you’re conscious, and they’ll give you a fancy TED Talk that means absolutely nothing.
They have theories. Diagrams. Brain scans lit up like Christmas trees. But none of that answers the big, stupid, beautiful question:
Why are we aware of anything at all?
1. Why On Earth Are You Even Aware?
Why do you have a “you” inside your head watching the show?
Science can tell you what neurons fire when you see a red apple. But it has no damn clue why you experience red. You don’t just process data. You feel things. That annoying little voice in your head narrating your life? No lab on Earth can explain where it comes from or why it exists. That thing you call “you” might be the biggest mystery in the universe.
The hard problem of consciousness is the question of how physical processes in the brain give rise to subjective experience — David Chalmers, philosopher of mind
2. Where Do Thoughts Come From?
You ever just catch yourself thinking about something random? A duck in a cowboy hat? Your third-grade teacher’s haircut? Where did that come from?
Neuroscientists can map which brain region lights up when you’re doing math or remembering a name. But they can’t track the original source of a new thought. Thoughts just… appear. Spontaneously. Uninvited. Like a pop-up ad in your brain. Try asking a scientist to predict your next thought. They can’t. And they probably won’t ever be able to.
No current theory explains how thoughts emerge from non-conscious neural activity — Christof Koch, neuroscientist
3. What Happens When You Sleep?
It gets even weirder. Almost all animals have to sleep. For example, dolphins can’t stop swimming or they’d die — so they evolved a trick. Sleep is so damn essential that nature found a way to cheat: dolphins let the left and right sides of their brain take turns sleeping. Half the brain sleeps while the other half stays awake to keep them moving. That’s how serious sleep is. Being half-conscious and vulnerable still beats skipping it. And science still can’t explain why it’s worth that risk.
The truth is, we don’t yet understand why we sleep or dream. We only know we have to — Matthew Walker, sleep scientist
4. Why Can You Be You With a Damaged Brain?
Some people lose half their brain and still function like normal. Kids with major brain damage can grow up speaking, walking, laughing. How?
Your consciousness doesn’t seem stuck in one spot. It moves. It adapts. You can cut a brain in half and get two minds in one skull (Google “split-brain patient” and be amazed). You can remove chunks of the brain and still get a person with personality and memories. So what the hell is the minimum brain for “you”?
The brain’s ability to rewire and relocate functions challenges our fixed ideas of where consciousness lives — V.S. Ramachandran, neuroscientist
5. How Do You Make Decisions?
You think you make decisions. You weigh options, pick one, act. Simple, right?
Except not. Your brain starts preparing for your action before you’re aware of deciding. It’s like the brain says, “We’re doing this,” and your consciousness just tags along pretending it made the call. Free will? Maybe just a clever illusion your brain runs to keep you from panicking.
The readiness potential appears before the subject reports the decision to move. This raises deep questions about the nature of volition — Benjamin Libet, neuroscientist
6. What Even Is a Self?
You think there’s a “you” in there. A little captain steering the ship.
But try to find that self in your brain. You won’t. It’s not in your thoughts, because those change all the time. It’s not in your body, because that gets replaced cell by cell. Your personality shifts. Your memories fade. So who’s left? What’s the constant “you”? Science can’t find a self. Just processes pretending to be one.
The self is a narrative the brain constructs. It’s not a thing. It’s a story — Thomas Metzinger, philosopher and cognitive scientist
7. Can Other Things Be Conscious?
Is your cat conscious? Your phone? A rock?
Science doesn’t even have a working definition of consciousness. We know we have it — probably. Maybe. But what about other creatures? Octopuses? They act weirdly human. What about AI? If it acts smart, is it aware? Nobody knows. And here’s the kicker: we may never be able to tell. You can only observe behavior. You can’t see consciousness.
We can’t test for consciousness directly. We rely on analogies to our own mind — which may miss the point entirely — Anil Seth, neuroscientist
The Verdict
Science can build rockets, cure diseases, and give you cat filters on Zoom. But when it comes to your mind? It’s still fumbling in the dark. Every answer leads to five more questions. And the biggest one might be: is the universe conscious too?
You’re not just a brain. You’re a mystery your brain hasn’t figured out yet.
Want to support my work to keep this space alive? You can do that here.
Sources and Further Reading
The Character of Consciousness — David J. Chalmers (2010)
Consciousness: Confessions of a Romantic Reductionist — Christof Koch (2012)
Being You: A New Science of Consciousness — Anil Seth (2021)
Why We Sleep — Matthew Walker (2017)
Phantoms in the Brain — V.S. Ramachandran and Sandra Blakeslee (1998)
The Ego Tunnel: The Science of the Mind and the Myth of the Self — Thomas Metzinger (2009)
Self Comes to Mind: Constructing the Conscious Brain — Antonio Damasio (2010)
This post was written and edited with the assistance of Grammarly.
Written by Tanner on Truth & Myths
I write about the myths that shape society, culture, and politics. Blunt takes, sharp history, no sacred cows. Read with curiosity. Leave with better questions.
本文於 修改第 1 次
|
|
自我和文化基於大腦神經網路 - Elizabeth Halligan
|
|
|
推薦1 |
|
|
|
我對下文作者哈里根女士觀點的批評，請見此文引言(該欄2025/12/30)。下文有其可觀之處，至少讓人耳目一新；我在此只介紹，不推薦；作者所言務請自行判斷後再做取捨。
請參閱此文、此文(該欄2025/12/30)、和拙作《唯物人文觀》。
The Neurology of Ego Death (DMN Collapse) and the Collapse of Civilization
Elizabeth Halligan, 09/01/25
Civilization isn’t failing because we lack solutions; it’s failing because most people’s brains won’t let them see the problem. The barrier to our survival isn’t technological, political, or economic. It is neurological.
This is a story that bridges the traditionally separate worlds of neurology and psychology. The “ego” isn’t merely a spiritual metaphor, something you encounter during an ayahuasca ceremony or a therapy session. It has a physical address in the brain: the Default Mode Network (DMN). This network is responsible for your sense of identity, continuity, and the continuous internal narrative we call the “voice in your head.”
The DMN runs when you’re not focused on a specific task — when you are daydreaming, worrying, imagining the future, or ruminating on the past. It is the architect of the story of “me,” weaving together a coherent narrative across time. But when this network is overactive and unintegrated, it can become a prison. This prison is the trauma loop, the cultural ego, and the inherited stories we mistake for reality. All of it is encoded in neural rhythm, a pattern so deeply defended that you can’t feel it’s running you instead of you embodying it.
Then, for some, a system-level event occurs — be it a trauma, a psychedelic experience, or a near-death experience — and the DMN can collapse. The ego dissolves. People who have experienced this report a feeling of becoming “everything,” merging with God, or experiencing a state of timelessness.
While these are profound spiritual experiences, they are rooted in a physical, neurological event: a decoupling of the brain’s networks.
This has a critical, species-level implication. The Default Mode Network is also a collective phenomenon. It’s how we align our inner worlds to co-create a shared “reality.” When a majority of individual DMNs are clinging to fear, control, and separation, the collective collapses the world into that very reality. The world you see is not an objective reality; it is, in a very real sense, a shared hallucination of eight billion DMNs, all out of sync and out of regulation, each trying to survive its own loop. This is not “human nature.” It’s pattern repetition fueled by millennia of unintegrated trauma.
So, what is locking us in?
The answer is the amygdala. The amygdala is the brain’s trauma guard dog, a primitive, fear-based survival mechanism. Its singular task is to keep the ego safe, even if that means keeping the person trapped in a self-destructive loop. It blocks access to a new reality if it perceives any threat, and to a traumatized system, even truth can feel like an existential threat. This is why it’s so difficult to “wake people up.” Their amygdala perceives new information as a threat to their survival, and it would rather have the certainty of a predictable story, no matter how self-destructive, than the uncertainty of change.
As a survivor of a high-control cult, I understand what it is like to be locked in such a loop. But I also know how the loop can be cracked. The key is not in battling the story from the outside, but in collapsing the DMN while the nervous system remains regulated. In this state, a new kind of perception opens. You don’t lose your Self; you remember what it always was. The true Self, unfiltered by constructs and illusions. It is not “me vs the world,” but a coherent, interconnected “We.”
This is the path of collective evolution. It is not a new technology, an AI savior, or a policy reform. It is a new center of coherence in human consciousness. A post-ego map. A species-wide nervous system update. You don’t have to be special to get there. You just have to be willing to feel what the amygdala locked away. To reclaim memory, regulate the body, and dissolve the story. Because the story isn’t you. It never was.
If you have already crossed this threshold, then hold the field, because others are tuning to you. If you have not, don’t worry, you are not behind. The pattern will unfold when it’s safe enough. And you will remember, not who you were…but what you’ve always been. Underneath the noise and filters. Your Self.
For further reading:
See my essay “Collapse Wasn’t Inevitable: We Locked Ourselves Out of Evolution” for a deeper dive into the thesis around neural plasticity and epigenetics as the true driver of human evolution: https://medium.com/@elizabethrosehalligan/collapse-wasnt-inevitable-we-locked-ourselves-out-of-evolution-d9101dc34c1c
When we turn down the Default Mode Network, the ego dissolves: https://www.iflscience.com/when-we-turn-down-the-default-mode-network-the-ego-dissolves-67685
The default-mode, ego-functions, and free-energy: a neurobiological account of Freudian ideas: https://academic.oup.com/brain/article/133/4/1265/307446?login=false
Default Mode Network
Written by Elizabeth Halligan
Systems theorist & consciousness researcher. I don’t monetize through the system. I work to shift it. To donate: https://venmo.com/u/Elizabeth-Rose85
本文於 修改第 1 次
|
|
用腦神經科學來思考哲學議題 - Rachel Barr
|
|
|
推薦1 |
|
|
|
以我對大腦神經學的了解，自然沒有資格對芭爾教授這篇論文說三道四。不過，我對「自由意志」、「人生的『意義』」、和「自我本質」這三個議題都很有興趣；也認真思考過；或許，可以借這個機會整合一下自己多年來的觀點。
3 philosophical debates from the 20th century that neuroscience is reshaping
Neuroscience isn’t dissolving philosophy’s hardest problems — it’s forcing us to rethink where they live.
Key Takeaways
* Modern neuroscience is reframing classic 20th-century philosophical questions about free will, meaning, and the self.
* Rather than eliminating these ideas, brain science shows how they emerge from the brain’s physical, probabilistic, and embodied processes.
* These debates now hinge less on abstraction and more on how brains actually work.
Rachel Barr, 12/22/25
Philosophers and scientists have always kept close company. Look back far enough, and it’s hard to tell where one ends and the other begins.
Featured Videos
3 powerful mind states: Flow state, good anxiety, and Zen Buddhism
Before we had instruments to measure reality, we had to reason our way into it, but that intellectual lineage is what eventually gave us the scientific method. As technology advanced and the scope for observation expanded, specializations splintered off from philosophy to reconstitute as the sciences.
Astronomy cleared the sky of deities and showed us a universe governed by gravity, not gods. Geography mapped a not-so-flat Earth, then geology dated it, stratifying earthly time in isotopes and sedimentary layers. Physics folded time into space, and with it, reimagined us not as beings apart from nature, but as a continuation of its energy and mass. We are not, as Pink Floyd suggested, “lost souls swimming in a fishbowl.” We are matter, muddling our way through life in relativistic motion.
Now, in the 21st century, science is tracing a map through the other great unknown: the mind.
Advances in biophotonics and neuroimaging have brought us closer than ever to a material picture of the mind, but the questions we’re now brushing up against aren’t melting away under empirical gaze. Instead, neuroscience has wandered back to philosophy’s front door, testing the limits of its most durable questions.
1. Free will
In the early 19th century, French physicist Pierre-Simon Laplace imagined the Universe as clockwork, each gear turning in obedience to natural law. He conceived of a demon who, knowing the position and momentum of every particle, could predict the future with perfect accuracy. This thought experiment crystallizes classical determinism: a world where there is no freedom, only inevitability.
Modern neuroscience can feel like Laplace’s demon in biological dress; if thoughts and actions arise from the physical machinery of the brain, are we anything more than cogs in the same cosmic clock?
Stanford neurobiologist Robert Sapolsky presses that case in Determined: A Science of Life Without Free Will. The deterministic nature of our neural universe, he writes, is a totalizing argument against free will. Every act is an inevitable output of prior conditions — from genes to stress to social context. Even the air in the room, he notes, subtly alters our behavior.
Some cases seem to justify his position. In Our Brains, Our Selves, Oxford neurologist Masud Husain tells the stories of patients who were dramatically reshaped by disease and injury. One such patient, David, developed profound apathy after a stroke damaged circuits that link the frontal lobes with the basal ganglia — structures heavily involved in motivation and action. He was awake, aware, and physically capable, yet the inner spark seemed gone. Neurologists call this syndrome abulia, the loss of will. Before treatment, others had to prompt him repeatedly to do even simple actions, but a simple dopamine-boosting medication restored David to his former ambitious self. Whether the drug restored free will is a philosophical question. What the case makes hard to deny is that whatever we call will — free or not — depends largely on the health of a few cubic centimetres of tissue and the concentration of a particular neurotransmitter.
Legal systems, psychiatry, and ethics all operate on a sliding scale of agency. Courts distinguish between crimes committed under premeditation and those committed under psychosis, for example.
This graded scaffold of responsibility sits more comfortably with the compatibilist view that determinism and free will can coexist. Philosopher and cognitive scientist Daniel Dennett has argued that freedom and responsibility arise from acting according to your own motives. The obvious objection is never far behind: “But where do those motives come from? Who chose them?”
This line of reasoning recurs endlessly in free-will debates — a philosophical whack-a-mole of causes causing causes. There’s a metaphor for this impasse: turtles all the way down. The phrase comes from a folk tale in which a scientist explains that the Earth orbits the Sun. A woman in the audience objects, “That’s nonsense, young man. The world rests on the back of a giant turtle.” When asked what the turtle stands on, she replies, “It’s turtles all the way down.”
One way out of this infinite regress is to stop sprinting back to the beginning of time and instead pay attention to what actually happens in the here-and-now of a living brain.
The past shapes us, but shaping is not the same as puppeteering. Causality is the medium in which agency emerges; it is a precondition of free will. A creature that could not be influenced by its history or environment would also be a creature that could not learn, plan, or take advice. In a very literal sense, you need causes in order to become the kind of system that can weigh options at all. As Dennett puts it, “the past does not control you; it causes you, but it does not control you.” Even the studies Sapolsky cites to illustrate biological and contextual determinism rely on statistics. They deal in distributions and averages, not one-to-one inevitabilities. For all practical purposes, brains and behavior must be described probabilistically.
Brains are not like the simple physical systems that populate a physics textbook. It is not a swinging pendulum, an ideal gas, or a neat circuit with a fixed input-output table. It’s a vast, nonlinear, adaptive network. Billions of neurons — each with thousands of synapses — form feedback-rich loops that are constantly being reshaped. When those neurons interact, their collective behavior no longer resembles a simple chain of causes.
At any moment, different coalitions of neurons can temporarily synchronise, form a functional team to guide perception or action, and then dissolve again. Neuroscientists describe this as a metastable system; it doesn’t lock into one pattern and stay there. The brain’s activity wanders across a landscape of possible patterns. Some regions of that landscape are attractors, preferred configurations the system tends to fall into. Others are ridges or passes that allow transitions between those attractors.
All of this is, of course, shaped by genetics and experience, but it doesn’t behave like a simple line of dominoes. Within this probabilistic terrain, neural circuits don’t dictate a single inescapable fate so much as bias the odds. Given your current state — your mood, your level of fatigue, the cues in the room — some patterns of activity are more likely to ignite than others. Causality constrains the menu of possibilities, but it does not pre-write the exact sequence of states you will traverse. This is where Laplace’s demon starts to lose its nerve.
Since the underlying dynamics are nonlinear, small differences in timing or input can, in the right conditions, be amplified into very different outcomes. Dynamical systems theorists call this sensitive dependence on initial conditions. In the brain, that sensitivity shows up at the boundary between competing options, where tiny fluctuations — an extra spike here, a few milliseconds’ delay there — can bias which attractor wins out. That isn’t indeterminism magically giving birth to freedom; rather, it is sensitivity placed where control signals can matter. It’s a thoroughly material feature of the brain’s organization that leaves the door to something like free will open a crack.
A decision does not require some magical breaking of the causal chain. It is a reconfiguration of the system’s dynamics: a shift in which neural coalition comes to dominate, a redirection of probabilistic flow through a lawful network. In theory, any non-zero degree of agency could be sufficient to move the needle.
To call this free will may stretch the term, but it captures a naturalistic form of agency, the ability of a physical system to use its own internal organization and history to navigate its causal possibilities. Neural computation operates squarely within the laws of physics. No synaptic transmission outruns light; no action potential violates Maxwell’s equations. Yet the brain transforms these laws into degrees of freedom. Brains are neither pure dice nor pure clockwork; they sit somewhere in between. That in-between space may be where whatever is worth salvaging under the name “free will” actually lives.
2. The existentialist crisis of meaning
Existentialism emerged from the collapse of theological certainty. In the 18th and 19th centuries, God was dead, or dying, and humanity found itself cut loose from the moral scaffolding that had once anchored its world. In the vacuum that followed, early existentialist thinkers, such as Søren Kierkegaard and later Friedrich Nietzsche, tried to rebuild with reason.
By the mid-20th century, after two world wars and the horror of Auschwitz, reason itself had come to look like a false idol. Writing amid the ruins of postwar Paris, second-wave existentialists Jean-Paul Sartre and Simone de Beauvoir found that both religious and secular systems of moral governance had crumbled under the weight of human brutality. What remained was the individual, alone with the burden of choosing.
For a paper-knife, Sartre explains, “essence precedes existence.” Its maker conceives its purpose first; only then is the knife brought into being. Humans have no such luck, however. We give knives their purpose, but who gives purpose to us? According to Sartre and many other existentialists, we do. Since meaning is not given, it must therefore arise from how we live and act in the world.
Albert Camus, writing a few years later, found this project misguided. The very hunger for meaning was the problem, he argued. The mismatch between that yearning and the Universe’s indifference is what he called l’absurde. Any attempt to reconcile this impossible correspondence was, for Camus, “philosophical suicide.” According to his view, we must live for “the struggle itself,” in full awareness of its futility.
Today, existentialism has entered a third phase — a movement philosophers Owen Flanagan and Gregg Caruso call neuroexistentialism. If consciousness is “the hard problem” in mind science, then “the really hard problem,” writes Flanagan, is explaining how subjective significance can arise in a purely material brain. His answer — eudaimonistic naturalism — suggests meaning can be studied empirically, by examining what allows human beings to flourish.
I don’t necessarily disagree. However, looking at it from my perspective turns this question slightly on its axis. Meaning, I would argue, is not something we elect to create; it’s something that happens to us. To be conscious at all is to translate sensation into experience. The brain cannot help but impose coherence on the flux of sensory data — stitching cause to effect, moment to moment — because that is the mechanism by which it constructs and perceives reality.
At Northwestern University, researchers asked volunteers to write about the past or future, imagining themselves in the experience. Whether the scenes they pictured were joyful or sad didn’t seem to matter — the very act of temporal simulation increased their reported sense of meaning. And the greater detail they imagined into the experience, the stronger the effect, on average. This suggests meaning is dialogical, emerging when engaged in process. The very act of being alive to our experience, and to time’s unfolding, appears to feed some part of our existential hunger, which, don’t forget, is the brain’s fault in the first place.
The brain constructs our hunger for meaning, just as it conceives of meaning in the first place. Nobody else experiences meaning, aside from, perhaps, some other intelligent creatures whose existential despair remains private. Meaning has always been a brain-made construct. It was ours to begin with.
Seen this way, Camus’ absurd takes on a new texture. The Universe is unfeeling because, of course it is. It’s the very environment from which feeling emerged. It provided a world of sensations, and then organisms evolved to feel them — spawning abilities to help them navigate material reality and, crucially, survive inside it. For what other reason could we have awoken, were it not for evolutionary pressures that privileged the survival of reality-sensing organisms? Absurdity is simply the natural condition of consciousness awakened from unresponsive matter.
We are, whether we like it or not, phenomenological creatures. However we define it, meaning is ultimately a felt sense of coherence and value, not a fact about the world but a relation to it. This shifts the existential task. Meaning isn’t something to be manufactured ex nihilo, but a felt sense that arises when we feed the brain the kinds of patterns and environments it reliably metabolises into a sense of coherence. Which is not unlike the eudaimonistic naturalism Owen Flanagan suggested. I did tell you I don’t necessarily disagree.
3. The self
If you follow the trail of 20th-century philosophers chasing the self, what strikes you is how restlessly the thing keeps moving. Martin Heidegger moved it out of the skull and into the world. In his view, selfhood is expressed in what you do, what you care about, and how your life is organized under the awareness of mortality, or “being toward death.”
Maurice Merleau‑Ponty tightened the focus from world to flesh, describing selfhood as a lived body. For him, the self isn’t a story you tell, but a pre-reflective feeling of mineness braided into perception and movement.
Derek Parfit located it in something more abstract: in the continuing causal organization of mental life. He arrived at this conclusion via a thought experiment. Imagine your brain is divided and transplanted into two new bodies. Which one is you? Parfit argues that identity, as we imagine it, can’t do the job we want it to, because identity can’t branch. Psychological continuity, however, can — and that, he thinks, is what really grounds your concern about the future. You plan ahead, assuming that your future self will remember your past, carry your intentions forward, and feel the consequences of what you do now. After the transplant, your life continues in two streams, and what you care about is present in both. So perhaps, Parfit suggests, “you” can survive as two.
Above, we have three different answers to the same question: Where does the ‘I’ live? At the turn of the millennium, a new candidate was discovered.
When you let your attention drift inward — to your past, your future, your inner monologue — the default mode network (DMN) kicks into gear. Neurologist Marcus Raichle first noticed it when certain midline areas would hum to life when his volunteers were waiting idly in the scanner between trials. Mind-wandering was the first function linked to this network. Since then, the DMN has been implicated in autobiographical memory, rumination, and self-referential thinking — exactly the sort of heavy lifting you’d expect from a narrative self-system.
When that network is perturbed, the felt shape of the self can change. Under psychedelics, the DMN becomes less internally coherent. As its activity falls away, so too does the bounded, narrating self — a state referred to as ego dissolution. At the same time, sensation and emotion flood more freely into awareness. Experience can feel more immediate and emotionally saturated, as if the editorial voice has gone quiet and the world has rushed in.
Depersonalization looks like the bleak mirror image. Here, DMN hubs chatter away, but their links to salience and interoceptive networks are weakened. The part of the brain that keeps up a running commentary about “me” is still humming, sometimes even overactive, but its conversation partners in the body and emotional brain have gone quiet. Patients describe feeling like a spectator sealed behind glass. They know who they are, and they remember the events of their lives. What’s missing is the felt mineness of experience.
Depersonalization exposes the limits of what Parfit’s psychological continuity can explain. Continuity may be enough to ground the forward flow of memory, intention, and character, but it is not sufficient for the phenomenology of selfhood. In depersonalization, the continuer persists; the mineness does not.
Experience is not a faithful readout of external reality, or of internal viscera; it’s the brain’s best Bayesian explanation of viscerosensory inputs. You can’t see your pupils dilate; you often can’t place a visceral shift precisely in space or time. That forces the brain to lean heavily on estimation models, making guesses that help it to integrate interoceptive signals — like heart rate, breathing, and temperature — with sensory feedback from the external world.
In depersonalization, the system appears to down-weight those interoceptive signals, treating them as noisy and uninformative. The DMN keeps rehearsing the script of the self, but it’s no longer anchored to the visceral stream coming up from the body. From the inside, that feels like your life continuing in theory while someone else does the living.
The brain is ultimately an organ of regulation, which is why cognitive neuroscientist Anil Seth describes us as “beast machines.” We are biological control systems first, reflective narrators only later. Nervous systems arrive late in evolutionary history, appearing as specialized gadgets for helping bodies anticipate and avoid trouble. Perception and action evolved in service of keeping the body alive, and so our experiences are never really disembodied.
Merleau‑Ponty was onto something, it seems.
Still, Seth relocates the self once more. He’s proposed that conscious selfhood arises from the brain’s role as a prediction-driven control system for the body. Feeling like a self, he argues, is the brain’s best effort to wrangle body, narrative, and world into a coherent stance. Selfhood lives in the connective tissue that binds story to sensation.
Psychedelics and depersonalization are instructive precisely because they pry those agreements apart. One loosens the narrator while flooding the body; the other preserves the narrator while muting ownership.
The primary project of a living system is not to understand the world; it is to avoid dying in it. Perception, action, memory, and even our hunger for meaning are elaborations of that basic constraint. The brain is not made of celestial material. It is tissue and salt water, warmed, fed, and continuously informed by the rest of the organism.
A brain removed from a body is not a mind; it is a rapidly failing organ.
Inside the organism that feeds it, the brain becomes a dynamical system that can model its own future, argue with itself about responsibility, suffer the absence of meaning, and feel like someone rather than something. We perceive the world and ourselves because of, not in spite of, being “beast machines.”
Sign up for Big Think on Substack
The most surprising and impactful new stories delivered to your inbox every week, for free.
Subscribe
本文於 修改第 3 次
|
|
意識所在之處 ---- Elizabeth Rayne
|
|
|
推薦1 |
|
|
|
下文報導或詮釋本欄2025/09/27柯頗納教授的論文。這是個重要又有趣的議題，值得多方面了解。
以我的了解，這當然只是外行人的外行話：「意識」離不開「記憶」；從而，神經學家也需要從和「記憶」相關的細胞、結構、機制、與大腦內部化學物質來了解「意識」。至少要加強這方面的實驗。
Scientists Think They Know Where Consciousness Lives In Your Brain
New research suggests that consciousness originates in the subcortex, and is polished by the cortex and cerebellum.
Elizabeth Rayne, 10/02/25
Experts Think They Know Where Consciousness Lives VICTOR de SCHWANBERG/SCIENCE PHOTO LIBRARY - Getty Images 請至原網頁觀看示意圖
Here’s what you’ll learn when you read this story:
* It used to be thought that without the cerebral cortex, consciousness could not exist.
* New research, however, has found that humans and animals missing part or all of their cortices are still capable of having experiences associated with consciousness.
* This research suggests that consciousness instead originates in the subcortex, and is polished by the cortex and cerebellum.
Whether consciousness is generated by quantum forces or connected to the entire universe is still up for debate, but even the theoretical physicists who suggest these complicated theories have not yet answered one question: Where are consciousness’ origins in the brain?
Peter Coppola, a neuroscientist from the University of Cambridge, sought to answer this question with an exhaustive analysis of brain studies going back decades. Consciousness is defined (at least in neuroscience) as “qualitative subjective experience, or ‘what it is like’ to be a specific organism in a specific state,” he said in a study recently published in the journal Neuroscience & Biobehavioral Reviews. Coppola wanted to see what the evidence said, rather than relying on the dominant theories.
While there are functions in all parts of the brain that contribute to consciousness, some might be more instrumental than others in giving us that awareness of who and what we are.
The prevailing thought is that consciousness arises from the outer-layer region of the brain called the cortex, which is mostly made up of the more-recently-evolved neocortex. The cerebellum at the base of the brain and the subcortex -- which includes the brain stem and has not seen much change in 500,000 years of evolution -- are thought to be involved in consciousness, but not so critical that they can power consciousness on their own. However, that might be about to change.
Through his research, Coppola found studies showing that animals with part or all of their cortices removed -- as well as humans who were born with conditions in which the cortex was partially missing -- showed that they were still conscious to some extent. To gauge consciousness in a lab, the researchers used observable behaviors related to vision, movement, and verbalization. But those indicators bring with them a few questions. Is movement automatic, such as blinking, or does it have a purpose? Is vision following something, or just a startle response? Is verbalization intelligent or nonsensical? Even the absence of certain behaviors does not necessarily mean a subject is not conscious.
Besides the brutal and ethically questionable animal studies in which researchers surgically removed part or all of the cortex, studies of human children born with a rare condition known as hydraencephaly were telling. Hydraencephaly occurs when the cerebrum does not develop, and is instead replaced by cerebrospinal fluid. The only parts left are the basal ganglia (a cluster of nuclei in the subcortex associated with motor control, reward, and cognition), the meninges (membranes that line the skull), and the brainstem (which has been linked to consciousness in the past).
Hydraencephaly often means a permanent vegetative state. However, studies of people born with the condition showed that their brains were capable of more than they appeared to be. In one case of a 32-year-old woman with a small part of her frontal cortex preserved, she was able to react to music with pleased facial expressions and vocalizations, even though the vocalizations were not understandable. This goes directly against the theory that consciousness cannot exist without the cerebral cortex. Observations from another study focusing on hydraencephalic children were similar.
Coppola’s research suggests that the base of consciousness lies in the subcortex, while the parts of the brain that evolved more recently -- such as the neocortex -- refine consciousness. However, this idea is highly nuanced, and further investigation is needed.
“If the embodied subcortex is truly sufficient for experience to emerge, then investigations may be undertaken to narrow down what specific subcortical functions engender experience,” he said. “[more research] may yield further insights as to minimal neural circuitry required for an experience.”
本文於 修改第 3 次
|
|
大腦神經學可能錯置意識關鍵部位 -- Peter Coppola
|
|
|
推薦1 |
|
|
|
Major theories of consciousness may have been focusing on the wrong part of the brain
Peter Coppola, University of Cambridge, 09/22/25
What gives rise to human consciousness? Are some parts of the brain more important than others? Scientists began tackling these questions in more depth about 35 years ago. Researchers have made progress, but the mystery of consciousness remains very much alive.
In a recently published article, I reviewed over 100 years of neuroscience research to see if some brain regions are more important than others for consciousness. What I found suggests scientists who study consciousness may have been undervaluing the most ancient regions of human brains.
Consciousness is usually defined by neuroscientists as the ability to have subjective experience, such as the experience of tasting an apple or of seeing the redness of its skin.
The leading theories of consciousness suggest that the outer layer of the human brain, called the cortex (in blue in figure 1), is fundamental to consciousness. This is mostly composed of the neocortex, which is newer in our evolutionary history.
Figure 1, the human brain (made with the assistance of AI). Peter Coppola, CC BY-SA 請至原網頁觀看人類大腦結構圖
The human subcortex (figure 1, brown/beige), underneath the neocortex, has not changed much in the last 500 million years. It is thought to be like electricity for a TV, necessary for consciousness, but not enough on its own.
There is another part of the brain that some neuroscientific theories of consciousness state is irrelevant for consciousness. This is the cerebellum, which is also older than the neocortex and looks like a little brain tucked in the back of the skull (figure 1, purple). Brain activity and brain networks are disrupted in unconsciousness (like in a coma). These changes can be seen in the cortex, subcortex and cerebellum.
What brain stimulation reveals
As part of my analysis I looked at studies showing what happens to consciousness when brain activity is changed, for example, by applying electrical currents or magnetic pulses to brain regions.
These experiments in humans and animals showed that altering activity in any of these three parts of the brain can alter consciousness. Changing the activity of the neocortex can change your sense of self, make you hallucinate, or affect your judgment.
Changing the subcortex may have extreme effects. We can induce depression, wake a monkey from anaesthesia or knock a mouse unconscious. Even stimulating the cerebellum, long considered irrelevant, can change your conscious sensory perception.
However, this research does not allow us to reach strong conclusions about where consciousness comes from, as stimulating one brain region may affect another region. Like unplugging the TV from the socket, we might be changing the conditions that support consciousness, but not the mechanisms of consciousness itself.
So I looked at some evidence from patients to see if it would help resolve this dilemma.
Damage from physical trauma or lack of oxygen to the brain can disrupt your experience. Injury to the neocortex may make you think your hand is not yours, fail to notice things on one side of your visual field, or become more impulsive.
People born without the cerebellum, or the front of their cortex, can still appear conscious and live quite normal lives. However, damaging the cerebellum later in life can trigger hallucinations or change your emotions completely.
Harm to the most ancient parts of our brain can directly cause unconsciousness (although some people recover) or death. However, like electricity for a TV, the subcortex may be just keeping the newer cortex “online”, which may be giving rise to consciousness. So I wanted to know whether, alternatively, there is evidence that the most ancient regions are sufficient for consciousness.
There are rare cases of children being born without most or all of their neocortex. According to medical textbooks, these people should be in a permanent vegetative state. However, there are reports that these people can feel upset, play, recognise people or show enjoyment of music. This suggests that they are having some sort of conscious experience.
These reports are striking evidence that suggests maybe the oldest parts of the brain are enough for basic consciousness. Or maybe, when you are born without a cortex, the older parts of the brain adapt to take on some of the roles of the newer parts of the brain.
There are some extreme experiments on animals that can help us reach a conclusion. Across mammals – from rats to cats to monkeys – surgically removing the neocortex leaves them still capable of an astonishing number of things. They can play, show emotions, groom themselves, parent their young and even learn. Surprisingly, even adult animals that underwent this surgery showed similar behaviour.
Altogether, the evidence challenges the view that the cortex is necessary for consciousness, as most major theories of consciousness suggest. It seems that the oldest parts of the brain are enough for some basic forms of consciousness.
The newer parts of the brain – as well as the cerebellum – seem to expand and refine your consciousness. This means we may have to review our theories of consciousness. In turn, this may influence patient care as well as how we think about animal rights. In fact, consciousness might be more common than we realised.
Peter Coppola, Visiting Researcher, Cambridge Neuroscience, University of Cambridge
This article is republished from The Conversation under a Creative Commons license. Read the original article.
本文於 修改第 1 次
|
|
大腦是意識存在的必要條件？-M. Gazzaniga/B. Queenan
|
|
|
推薦1 |
|
|
|
嘉薩尼嘉博士為《大腦比你先知道》一書作者；下文見解深遽、非常有趣、更是以生花妙筆娓娓道來；不愧是大師。對「意識」或大腦神經學有興趣的朋友請慢慢欣賞、咀嚼。
Is your brain really necessary for consciousness?
People with missing brains make clear the mystery of consciousness
Michael Gazzaniga/Bridget Queenan, 08/05/25
Editor’s Note：We think that the bigger the brain, the more developed the consciousness. Humanity prides itself over the rest of the animal kingdom for having larger brains, but neuroscientist Michael Gazzaniga and his colleague Bridget Queenan explore cases of people living full lives with shockingly little brain matter. Challenging the “more is better” bias, they suggest consciousness may be less about structures, and more about harmony and improvisation.
In 2007, a strange headline made its way around the world: the mysterious case of the white-collar worker “without a brain.” On the outside, a normal 44-year-old: employed, married, with two children and an acceptable IQ. On the inside, a gaping fluid-filled cavity where a brain would normally be. There was a hole in this story: How can a person lead a full and functional life while missing most of their brain?
These days, headlines feature a different white-collar worker “without a brain”: the AI systems writing emails, book reports, and manuscripts in schools and offices worldwide. Now we have another hole in our story: How can a person lead a full and functional professional life without using their brain?
Both developments challenge our already fragile definitions of “consciousness.” It may be time for a new approach to brains and “consciousness”—as the music of the mind.
As Long as she got a dime the music will never stop
The case of the missing brain is rare, but not unique. A 2013 case reported a 60-year-old missing the back of her brain. Again, normal on the outside: employed until recently, married, with one child and the ability to live alone. Inside, a cavity where the cortex should be. A 2018 case reported a 60-year-old, unmarried and unemployed, but active in a band and a choir, with his head full of fluid and only a thin sheet of cortex. A 2021 case reported a 72-year-old living independently, again largely without what we might recognize as “a brain.” Even rats got in on the action: R222 lived well into adulthood, performing well in lab-rat escapades despite a hollowed-out brain.
Collectively, these findings suggest that the human (and rat!) brain is considerably more plastic than expected. If you were born with bones or muscles half the expected size, or a quarter, or a tenth, you wouldn’t carry on unimpeded. If you were born with a tenth of your liver, we’d have a problem. Yet, somehow, the human brain can rise to the occasion—at a performance review, a brain can pass inspection; only after imaging, do we see it’s just 3 owls in a trench coat.
Now, if you are born with no cortex (hydranencephaly), things look bleak. But apparently you can get by on a lot less cortex than we thought (ventriculomegaly). When it comes to the developing human brain, you might not need the whole dollar—if you’ve got a dime, you can keep the jukebox jumping.
It’s such a sight to see somebody steal the show
“No-brainer” stories make headlines for three reasons:
1. It looks wrong: In the era of modern brain imaging (CT, MRI, PET), we know what brains look like, and these brains don’t look right. Our entire nervous system (brain + brainstem + spinal cord) is floating in cerebrospinal fluid, and our brain has a few cisterns (“ventricles”) which keep the operation pristine. But the cisterns shouldn’t be that big. If you look inside the skull of a normal adult, you see mostly brain, with some fluid in the center and around the edges. If you look inside the skulls of our friends above, you see mostly fluid with only a thin layer of brain on the outskirts—the central cisterns (the ventricles) seem to have overflown completely.
2. Fluid is bad: When the central cisterns (ventricles) overflow in adulthood, bad things happen. The adult skull is a fixed volume, and the adult brain has grown accustomed to its space. If excess fluid accumulates in the skull, it will infringe on your brain’s territory, squishing it as it tries to work. Accordingly, in adulthood, the progressive filling of the skull with excess fluid (hydrocephalus) impairs cognitive, behavioral, and motor function. Shunts need to be installed to drain the fluid. Yet, apparently, folks can grow up with a different ratio of brain-to-fluid: a skull full of fluid and a brain that can work around it. Their brain and its fluid shared the space fine, just in a different arrangement than is found in other folks’ skulls.
3. Brain is good: We have assumed for several centuries that it’s the brain part of the nervous system that does the thinking, the working, the talking, and the living. If folks are walking around, chit-chatting, getting jobs, getting married, raising children, and running their lives with a lot less brain than expected, it raises some serious questions about how we approach the conscious mind.
At the core of these concerns, we find only one issue: We assume it is possible to see whether brains are working well or poorly. We take a picture inside a person’s skull, measure how much brain they have in different places, and pronounce: too much, too little, and just right. Volumetric brain analyses assume that the overall volume of brain tells you how well those areas are working. Lots of brain volume in the memory area = good memory; little brain volume in the memory area = bad memory.
None of this seems unreasonable. It’s great to see things with your eyes. More is more, and less is less. But might it be unreasonable to care only about the volume? Might it even be kind of ridiculous to expect we could see it with our eyes?
It goes to show you never can tell
The volume of music is not the sole determinant of whether a song is good. The volume – the overall amount of sound participating at any given time—is one dimension of music, but there are many other components: the rhythm (low frequency waves which entrain the entire song), the harmony (higher frequency waves which structure the sound), the melody (highest frequency waves which tell the story). Music is the elaborate interplay between waves of sound, or vibration, in small, medium, and large (fast, medium, and slow), which braid together in a way that seems beautiful.
Similarly, the “volume” of brains is not the sole determinant of whether a brain is good. The volume —the overall amount of brain participating at any given time—is one dimension of brain activity, but there are many other components: the circadian rhythms (low frequency waves which entrain us to the Sun and seasons), the central pattern generators (higher frequency waves which structure our heartbeat and our breathing), the real-time brain activity (highest frequency waves which allow us to analyze the world and tell the story). A conscious mind is the elaborate interplay between waves of neural activity in small, medium, and large (fast, medium, and slow), which braid together in a way that seems beautiful.
It is easy to quantify the volume of music. You measure the total amount of pressure exerted by the air waves. It is harder to quantify the rhythm (especially for certain cultures). It is shockingly difficult to quantify the harmonies and melodies (ask anyone who has tried to study music theory).
It is (relatively) easy to quantify the volume of brains. You measure the total amount of signal detected in the scanner. It is harder to quantify the circadian rhythms (which are not necessarily identical based on latitude or season). It is shockingly difficult to quantify neural activity from regularly firing neurons, let alone from neurons that only respond to certain things (ask anyone who has tried to record from awake behaving brains).
In both cases, volume tells you some of the story, but not all of it. Great music isn’t the music played at the highest volume. Same apparently goes for brains.
Roll Over Beethoven
Volumetric analysis focuses on the brain’s appearance, and, admittedly, the human brain is arranged like an orchestra. There is a central ‘conductor’ (the brainstem) in our neck. Other parts of the brain form a vague semicircle, with everyone oriented towards their bandleader in the brainstem. Seated closest to the conductor, we find the hypothalamus and thalamus. Seated around them in a larger semi-circle, we find the basal ganglia. Seated beyond, in the largest arc, we find the cortex—the choir seated behind the orchestra.
Modern brain imaging has made us familiar with this orchestral arrangement. Neuroscientists have determined which part of the brain does what—we can point to a spot on a brain scan and tell you who sits there and what part they play—language is here, vision is there, memory is in that section.
However, modern brain imaging now demands that “normal brains” be orchestrated like Beethoven’s 9th Symphony—we expect to see an enormous orchestra of brain with a large choir in the cortex. We demand to see a stage (skull) full of musicians (brain areas) arranged in a specific way.
That’s why we’re surprised to see our friends “without brains”—it appears they have a bandleader in the brainstem and a small choir in the cortex, but they don’t have any of the “instruments” in the middle. We are surprised these folks’ brains can produce full and functional “consciousness”—the music of the mind—out of only a conductor and a choir.
As anyone familiar with the Gospel tradition knows, you can do a whole lot with “just” a conductor and a choir. In the absence of any instruments whatsoever, a Gospel choir can generate the rhythmic, harmonic, and melodic components of music in a way that is not just acceptable, but transcendent.
Tell Tchaikovsky the news
A stage full of instruments can be lovely, but it’s not a requirement for music. A great Gospel choir is more than capable of taking matters into their own hands, literally. They can easily outperform an entire orchestra of musicians, no matter how large.
A skull full of brain can be lovely, but it’s not a requirement for consciousness. Our friends above proved you can lead full and functional lives with “only” a cortex. These folks had a cortical choir that really knew what it was doing.
Music helps us expose the inherent problem with the volumetric approach to brains. We can point to the brass section of an orchestra or band and confidently tell you where the trumpet and sax should be sitting. But that doesn’t tell you what piece they’re going to play or when. It doesn’t tell you whether they’re good or bad. The only thing you can see about an orchestra or band is how big a section is. If your brass section is no good, smaller is better. Same goes for brains—we can tell you how a brain is orchestrated (how big each section is), but we have to wait for the performance to determine whether that’s good or bad news.
We can’t see music, but we have learned to understand it. Perhaps it’s time to officially learn certain lessons from music. How would we define “consciousness” from a musical perspective?
It’s got a backbeat you can’t lose it
We tend to talk about consciousness as an object: you can have it or not, you can lose it, you can regain it, you can acquire it. But consciousness is not an object—it’s a rhythm.
When it comes to brains, the only absolute requirement—for life—is that the bandleader in the brainstem keeps time. If your brainstem can no longer keep time, you are “braindead”: your body can no longer generate the rhythms needed to beat your heart, expand your lungs, etc.
When it comes to brains, the only absolute requirement for consciousness is that you have a choir in your cortex making music. You can’t be awake and conscious without any cortex. But a small cortex choir that knows what it’s doing can handle things just fine.
About 75 years ago, Chuck Berry started summarizing this situation in his lyrics. “It’s got a backbeat you can’t lose it” isn’t a musical philosophy—it’s a physiological reality: if the bandleader in your brainstem loses the backbeat, you are dead, not just musically and metaphorically, but medically. That same song contains an important insight into consciousness: “That’s why I go for that rock n’ roll music any old way you choose it.” It simply doesn’t matter how your brain gets there. You can be good in a lot of different ways.
Got no kick against modern jazz, unless they try to play it too darn fast
There are a few basic requirements for consciousness, just like there are for music.
We recognize features of music that make it unacceptable: we can pinpoint when someone is massively off-beat or out of tune. However, we don’t have a formula for “great music.” We recognize characteristic features of different genres of music: music from Western Europe, West Africa, and the West Indies tends to play by different mathematical rules, so we can guess which calculations were made in which musical tradition. But we haven’t explained how certain musicians assembled constellations of waves into arrangements so exquisite that they changed the course of human history. We can’t articulate why music is great—we just know it when we hear it.
Similarly, we recognize features of brain activity that make it unacceptable: we can pinpoint when someone is having a seizure or a stroke. However, we don’t have a formula for “great minds.” We recognize characteristic features of different genres of mind: the consciousness of artists, activists, athletes, musicians, scientists, soldiers, and writers presumably play by different mathematical rules, so we can guess which calculations were made in which mental tradition. But we haven’t explained how certain minds assembled constellations of waves into arrangements so exquisite that they changed the course of human history. We can’t articulate why minds are great—we just know it when we see it.
We can explain what makes music bad, though it’s much harder to explain what makes it good or great. That’s why we need to build a definition of consciousness from the ground up.
Sitting down by the rhythm review
If we approach the human nervous system from a rhythm perspective, we can define specific classes of consciousness. In fact, we can guess that the human mind categorizes states of consciousness (in others) by observing the rhythms those bodies display:
* Dead = generates no waves, an instrument or band that is silent
* Asleep = generates a simple polyrhythm (the beat of heart v. breathing). Humans expect to observe characteristic “tempos” in each other when at rest. We expect to observe a heart rate of 40–60 beats per minute (largo to andante) and a breathing rate of 12–20 breaths per minute (below grave, slower than a funeral dirge).
* Awake = generates a complex polyrhythm (beat of heart vs. breathing vs. blinking vs. moving). This body appears to contain a whole rhythm section, and they’ve picked up the pace. For example, we expect to observe a heart rate of 60-100 beats per minute (andante to moderato) and a blink rate of 4–25 beats per minute (again, below grave).
* Awake and aware = generates a complex polyrhythm that can change and evolve in response to circumstance (the rhythms of heart vs. breath vs. blink vs. move can change independently, producing a new polyrhythm on demand). This body appears to contain a whole rhythm section that can “jam” or “improvise.”
However, if we use these quantifiable rhythmic definitions of consciousness, we will find that humans aren’t the only ones who can play. Chimps, crows, dogs, dolphins, orcas, octopi, and elephants have already made strong cases that they should be admitted to the academy—they demonstrate the sophisticated music of the mind we call “consciousness.”
Never ever learned to read or write so well
Historically, we have denied animals (and plenty of humans) a place in the consciousness club because they don’t write lyrics. Humans have been the great lyricists of the planet—we have the capacity for “language,” meaning we can write lyrics to accompany the music of the mind.
Lyrics are not the same as music. Language is not the same as consciousness. Plenty of composers —Beethoven and Tchaikovsky among them—are in the Pantheon of “Great Composers” for music alone. We don’t require them to handle the words. We only seem to demand words when we want to exclude members from the club.
It’s time to admit that many living creatures aren’t so great at language, while being perfectly good at consciousness. They are musicians, but not singers; they are composers, but not librettists—get over it and move on. Johnny B. Goode “never ever learned to read or write so well, but he could play a guitar just like a-ringing a bell.” A brain capable of generating the music of the mind gets to join the consciousness club, just like a musician who can play gets to join the band, regardless of whether they sing and write songs, too.
These are particularly timely discussions considering that AI systems are being trained daily to outperform us on language. We are outsourcing our lyric writing, meaning we are turning ourselves into Johnny B. Goode. Soon, we may have to defend our own inability to read and write so well. Hopefully, our consciousness will still be recognized as present and valid.
Any ol’ way you choose it
There is a long history of policing consciousness, just as we police music—“official” schools and conservatories determine which form is “correct” or preferable or allowed. These schools of thought pretend there is one way to “do consciousness” just as they pretend there is one way to “do music” —they are therefore always hilariously and tragically wrong. Consciousness, like music, is not a single physical object, nor is it a specific performance tactic. Consciousness, like music, emerges when a body tries to braid waves together into something coherent. However badly someone is playing or singing, rising or shining, we recognize what they’re trying to do: play. “Consciousness,” like “music,” is a standard of proof: the minimum performance necessary for us to recognize a fellow performer. You can have beginner, intermediate, and advanced performers, but if you really care about music, you want everyone to get involved. If you really care about consciousness, you should feel the same.
When Berry ushered in the new musical and mathematical philosophy of rock’n’roll, he didn’t throw out Beethoven—he just told Tchaikovsky the news: “My heart’s beating rhythm and my soul keeps a-singing the blues.” When it comes to brains, your brainstem is beating rhythm and your cortex is a-singing the blues. The music you make with those components is all “you.”
Neuroscience hasn’t yet experienced its rock’n’roll revolution. We’re still largely pretending there’s a “correct” way of doing things. We don’t yet have lots of different radio stations celebrating lots of different types of consciousness, in different folks and different species. But we will, especially if musicians help out. Stay tuned.
Michael Gazzaniga is a renowned cognitive neuroscientist known for pioneering research on split-brain patients.
Bridget Queenan is a researcher who led the NSF-Simons Center for Mathematical Biology at Harvard and the Brain Initiative at UC Santa Barbara.
Related Posts:
The neurodivergence paradox
The reality gap
Phone addiction is worse than smoking or cocaine
Forgetting is more important than remembering
SUGGESTED VIEWING
Consciousness beyond the brain With Rupert Sheldrake
Consciousness and material reality With Avshalom Elitzur
Consciousness in the clouds
The normal and the abnormal
We misunderstand mental health
A Mad World
本文於 修改第 1 次
|
|
決定那些性質能顯示「意識」 - Tim Bayne
|
|
|
推薦1 |
|
|
|
不客氣的說，下文前半段在「喃喃自語」或玩文字遊戲。在我們對「意識」的性質有共識之前，不可能對顯示「意識」的「徵象」取得共識。這種「哲學家」真是把書讀到膝蓋裏去了。
順著作者最後一段所表達的意思，我或許可以說：
根據多數意識理論科學家目前對「意識」(性質)的「共識」，意識實驗科學家應該試圖尋找能顯示研究對象具有這類「意識」的各種「徵象」。它們能夠幫助意識理論科學家增加對「『什麼』是『意識』」的了解，從而做為建立一個「意識」精準「定義」的基礎。
Babies, bees and bots: On the hunt for markers of consciousness
To truly understand consciousness, we need new methods to measure it and detect it in other intelligent systems.
Tim Bayne, 07/30/25
請至原網頁觀看示意圖
One of the key scientific questions about consciousness concerns its distribution. We know that adult humans have the capacity for consciousness, but what about human neonates, bees or artificial intelligence (AI) systems? Who else—other than ourselves—belongs in the “consciousness club,” and how might we figure this out?
It is tempting to assume, as many do, that we need a theory of consciousness to answer the distribution question. In the words of neuroscientists Giulio Tononi and Christof Koch, “we need not only more data but also a theory of consciousness — one that says what experience is and what type of physical systems can have it.” This is what philosopher Jonathan Birch has labeled the “theory-heavy” approach to the distribution problem.
But there are serious issues with the theory-heavy approach. One is that we don’t have a consensus theory of consciousness. In a highly selective review that Anil Seth and I published in 2022, we listed no fewer than 22 neurobiological theories of consciousness. This overabundance of theories could reasonably be ignored if most agreed on fundamental questions in the field, such as which systems have the capacity for consciousness or the question of when consciousness first emerges in human development, but they don’t.
A further problem with the theory-heavy approach is that in order to speak to the distribution problem, a theory cannot be restricted to consciousness as it occurs in adult humans, but must also apply to human infants, nonhuman animals, synthetic biological systems and AI. But because theories are largely based on data drawn from the study of adult humans, there will inevitably be a gap between the evidence base of a general theory and its scope. Why should we think that a theory developed in response to adult humans applies to different kinds of systems?
This isn’t just an issue of the legitimacy of applying theories developed from adult human data; it also concerns how the theory itself is specified. A comprehensive theory needs to distinguish features that might be essential to (adult) human consciousness but are not essential to consciousness as it might occur in other systems. However, it’s not clear how that distinction can be drawn if our primary data are drawn from the study of adult humans.
In light of the challenges facing the theory-heavy approach, many have tried to develop an alternative approach to the distribution problem: the marker approach. Think of markers as a bit like a detective’s clues. Rather than constituting proof of consciousness, markers need only be indicative (or “credence-raising”). Converging evidence of different types of markers might establish the presence of consciousness, in the same way that evidence from various clues might establish guilt beyond a reasonable doubt.
The basic idea behind the marker-based approach isn’t entirely new. Consider the fact that in ordinary life, we rely on capacities for agency and verbal communication to ascribe consciousness to other people. These behavioral markers of consciousness are crucial in clinical contexts. For example, the capacity to reliably follow commands is taken to be an indicator of consciousness in severely brain-damaged patients.
But behavioral markers have their own limitations. The capacity to produce intelligent linguistic behavior is one of the most trustworthy markers of consciousness in humans, but few of us are inclined to regard the linguistic behavior of large language models such as ChatGPT or Claude as evidence that they, too, are conscious. There are also cases—involving cerebral organoids or neonates, for example—in which consciousness might exist in the absence of complex behavioral capacities. If the marker approach is to make serious headway against the distribution problem, behavioral markers will need to be supplemented with nonbehavioral markers, such as those that involve neural, physiologic, metabolic or computational features.
Whatever form they take, markers will need to be validated, and we need to reach a consensus on when and why we should trust them. How, then, shall we proceed?
The standard approach appeals to the contrast between conscious and unconscious states in our consensus population (that is, adult humans who can report on their experiences). To see how this works in practice, consider a marker that has received significant attention recently: the “global effect.” Developed by Tristan Bekinschtein and his colleagues at the University of Cambridge, the global effect exploits the fact that consciousness appears to be required for a certain type of auditory “oddball.” It has long been known that when people are exposed to a sequence of identical tones followed by one that differs in some way (the oddball), the brain generates a “surprise” response to the stimulus. This response is known as the P300 response, because it occurs roughly 300 milliseconds after the oddball. What Bekinschtein and his colleagues found is that the brain produces P300 responses to local (or “first-order”) oddballs (e.g., AAAB) even when a person is unconscious, but consciousness does appear to be required for P300 responses to global (or “second-order”) oddballs, such as those taking the form AAAB AAAB AAAB AAAA.
Taking inspiration from this finding, theorists have suggested that the global effect might be indicative of consciousness in other populations. For example, the fact that it can be found in 3-month-old infants, newborns and perhaps even in fetuses past 35 weeks’ gestational age has been taken by many to provide some evidence in favor of consciousness in early infancy (and, more tentatively, in late-stage fetuses).
Although I myself have used data about the global effect to justify claims about the emergence of consciousness in human development, this line of reasoning is not immune to criticism. The problem is that neural responses functioning as markers of adult consciousness might not function as markers of infant consciousness. And there are questions about how well the global effect tracks consciousness in systems that are even less like “us” than infants or fetuses are. Finding a global effect in an AI system surely provides little to no evidence that it is conscious.
The upshot, then, is that we need principled ways of identifying the scope of putative markers of consciousness—an account of when features that indicate the presence (or absence) of consciousness in us also indicate the presence (or absence) of consciousness in systems that are very different from us. If such an account requires a theory of consciousness, then the marker-based approach collapses back into the theory-heavy approach. Is there a middle ground between these two approaches?
Perhaps. Together with various colleagues, I’ve suggested that we can bootstrap our way toward a solution to the distribution problem by a process of iterative revision. For example, we use our most promising theories of consciousness to tell us when the global effect is a reliable guide to the presence of consciousness, and we use what our markers tell us about the distribution of consciousness to further refine our theories. Eschewing foundationalism, we should regard neither theories nor markers as sacrosanct but look for an account that maximizes the fit between them.
Tim Bayne, Professor of philosophy, Monash University
本文於 修改第 1 次
|
|
夢的功能 -- Clarissa Brincat
|
|
|
推薦1 |
|
|
|
我不是醫學院或生命科學領域出身；我的意見自不過是門外漢的道聽塗說。根據我的經驗以及讀過的相關書籍、論文、和報導，我認為：「夢」屬於意識活動種種形式中的一個；因此，我把下文歸於此欄。
What’s the purpose of dreaming?
Dream experts have plenty of possible answers.
Clarissa Brincat, 06/16/25
Your brain never rests. Image: PM Images/Getty Images5 請至原網頁觀看示意圖
We all dream — but why? As with many mysteries of the mind, science doesn’t have one neat answer.
“You’ll get as many answers to the question ‘What is the purpose of dreaming?’ as there are dream psychologists,” says Deirdre Barrett, dream researcher at Harvard University and author of The Committee of Sleep.
According to Austrian neurologist and founder of psychoanalysis Sigmund Freud, dreams offered vital clues to unresolved conflicts buried deep within our psyche. But Freud’s theory, introduced in his 1899 book The Interpretation of Dreams, sparked plenty of controversy. Critics argued that his dream interpretations were overly focused on sex, highly subjective, and impossible to verify—two analysts might offer entirely different readings of the same dream, with no objective way to know who was right.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
In the decades since Freud, other scientists have offered alternative explanations for why we dream. One of the most prominent is the threat simulation theory, proposed by Finnish neuroscientist and psychologist Antti Revonsuo in 2000. According to this view, dreaming is an ancient biological defense mechanism. By simulating dangerous situations, our brains rehearse the skills needed to recognize and avoid threats—a kind of virtual reality training ground for survival. A 2005 study lent support to this theory by examining the dreams of Kurdish children exposed to war and trauma. Compared to non-traumatized Finnish children, these children reported more frequent dreams filled with severe threats, suggesting that their minds were practicing how to cope with danger.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
But even the threat simulation theory is debated. A 2008 study comparing residents of high-crime areas in South Africa to those in low-crime parts of Wales found that South African participants, despite facing more real-world threats, actually reported fewer threatening dreams than their Welsh counterparts. This result challenges the idea that the brain uses dreams to simulate danger when exposed to trauma.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
Another theory suggests that dreams are simply a side effect of memory consolidation—the brain’s way of replaying and reinforcing new memories while we sleep. As the brain’s hippocampus and neocortex work together to file away fresh information, they may also blend it with older memories, creating the often strange mashups we experience as dreams.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
Dreams may also help us process and manage emotions, especially negative ones, according to the emotion regulation theory of dreaming. Research focusing on recently divorced individuals experiencing depression found that participants who dreamed about their ex-spouses were more likely to show significant improvement in their mood one year later, particularly if their dreams were vivid and emotionally rich. Another study found that people who dreamed about stressful events they had experienced before sleep woke up feeling more positively about the events the next day, suggesting that dreams can help transform emotional distress into resilience.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
Recent brain imaging studies support this idea. People who frequently experience fear-related dreams show reduced activation in fear centers of the brain during waking life, hinting that these dreams may serve as a kind of overnight therapy session, helping us better regulate our emotions when awake.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
Ultimately, Barrett suggests that we may be asking the wrong question. “We’d rarely ask the analogous question: ‘What is the purpose of thinking?’” she says. Just as waking thought serves many functions—from planning to problem-solving to daydreaming—dreams likely do too. “The value of dreaming lies in its difference. It’s a distinct mode of thought—one that supplements and enriches our waking cognition.”
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
In fact, some researchers believe dreams offer a unique mental space for solving problems that stump us during the day. In this altered brain state, regions responsible for imagery become more active, allowing the mind to solve problems requiring visualisation. History is full of famous examples: Mary Shelley reportedly dreamed the central scenes of Frankenstein; German chemist August Kekulé envisioned the ring structure of benzene in a dream; and Russian chemist Dmitri Mendeleev dreamed his final form of the periodic table of the elements.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
In the end, dreams may serve many purposes—or none at all—but they remind us that even in sleep, the brain never truly rests.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
This story is part of Popular Science’s Ask Us Anything series, where we answer your most outlandish, mind-burning questions, from the ordinary to the off-the-wall. Have something you’ve always wanted to know? Ask us.
Trump is already lowering the bar on China tariffs blasting President Xi as ‘hard to make a deal with’
Related Sleep Stories
* Can tracking make my sleep worse? The quiet torment of sleep tech.
* Why do some people need less sleep?
* Poor sleep can make you more susceptible to conspiracy theories
* How to fix your sleep schedule without pulling an all-nighter
* 5 reasons you can’t sleep
本文於 修改第 1 次
|
|
|
本城市首頁
看回應文章
等級：8
