Brain Science with Ginger Campbell, MD: Neuroscience for Everyone

Episode BS 212: Thomas Metzinger on "The Ego Tunnel" (Encore)

Date: September 22, 2023
Guest: Dr. Thomas Metzinger, philosopher, author of The Ego Tunnel
Host: Dr. Ginger Campbell

Overview

This episode is a replay of Dr. Ginger Campbell’s insightful 2010 interview with philosopher Thomas Metzinger, exploring the ideas behind his influential book The Ego Tunnel. Metzinger bridges philosophy and neuroscience, focusing on the nature of consciousness, the notion of self, the function of conscious experience, and the ethical implications of our growing understanding of the mind. The discussion is accessible yet deep, covering altered states, virtual reality experiments, and how advances in mind science challenge our traditional self-image.

Key Discussion Points & Insights

1. Metzinger’s Background and Motivation

• Interdisciplinary Philosophy: Metzinger details his philosophical education and commitment to bridging philosophy of mind with neuroscience, AI, and neuroethics.
• Purpose for The Ego Tunnel: He aimed to make philosophical issues about consciousness accessible to lay readers and to connect them with ethical and anthropological questions.

  “I wanted to try if I can write a book that is accessible to normal people ... which combines just those issues in the field of consciousness research, of which I think these are the important issues everybody should know about.” (03:08)

2. Defining Consciousness

• Consciousness as a Bundle of Problems:
  • Metzinger describes consciousness as multifaceted: mind-body problem, intentionality, unity of consciousness, and especially subjectivity.

  “It is not one problem. It’s a whole bundle of problems.” (09:38)

• The First-person Perspective:
  • The subjective, felt experience is unique to consciousness and central to its mystery.

  “My very own sensation of green, or my very own feeling of happiness and relaxation is not a public object… it is, in a sense, which we haven’t fully understood, subjective.” (11:39)

• Working Definition:
  • Consciousness as “the appearance of a world” (12:52)—that, whether waking, dreaming, or hallucinating, what matters is the qualitative appearance to the subject.

3. The Ego Tunnel Metaphor & The Illusion of Self

• The ‘Ego Tunnel’:
  • Conscious experience is an internal, virtual simulation generated by the brain—the “appearance of a world” is a user illusion.

  “Conscious experience is, so to speak, Mother Nature’s own virtual reality … It is a simulated internal space.” (24:39)

  • Despite being generated in the brain, it feels as if we are really “in the world.”
• Self as Process, Not Thing:
  • Metzinger denies the existence of a substantial self, favoring a process-model:

  “What we have called the self… is not a thing, but it’s a process. And it’s a process that’s not always there.” (30:45)

• The Self-model:
  • The brain creates an “ego” or “self-model”—a simplified, user-illusion necessary for managing complexity and control.
  • The conscious sense of self boots up with wakefulness, is altered in dreams, and vanishes in deep sleep.

4. Consciousness as a Biological Process

• Embodiment and Evolution:
  • Consciousness (and subjectivity) is assumed to be strongly biologically determined and subject to evolutionary rationale.
  • The evolutionary advantage: Having a model of one’s own body and self (even before it’s conscious) provides survival benefits—flexible behavior, attention, concept-formation, and motor control.
  • Sleepwalkers:

    “Sleepwalkers do run into furniture and into walls. Sleepwalkers do fall downstairs. … They are more like a simple robot.” (19:41)

  • Conscious attention allows rapid, fine-grained adaptation.

5. Altered States and Out-of-Body Experiences

• Comprehensive Approach:
  • Metzinger insists any adequate theory of consciousness must account for altered states: dreams, hallucinations, mystical experiences, psychiatric conditions like Cotard’s syndrome.
• Out-of-Body Experiences (OBEs):
  • OBEs as Natural Phenomena:
    • OBE research reveals the bodily component of selfhood and shows that the unity of the self can be experimentally manipulated and divided.
  • Rubber Hand & Full-Body Illusions:
    • Metzinger describes collaborating on experiments that induce body-identification illusions via virtual reality, paralleling the famous “rubber hand” illusion (42:40).
    • Key finding: Multisensory integration and movement feedback “anchor” the self to the body, but when cut off (paralysis, anesthesia), alternate self-models arise, as in OBEs.

    “Your body is a very special perceptual object. It always bombards the brain with a lot of information… The body model is also philosophically interesting because it’s the only image in our mind of which you know, the object of reference is always there.” (51:44)

  • Body Emulator and Motor Loops:
    • The brain’s ability to emulate body movements in advance is crucial for efficient behavior and underlies much unconscious expertise.

6. Ethical & Societal Questions

• The “Naturalistic Turn”:
  • Advances in neuroscience and philosophy are naturalizing the mind, challenging traditional, often comforting images of the self and human exceptionalism.

  “Our image of ourselves is changing through all of this research, if we want it or not… even our mental properties are results of a process that had no direction, that pursued no goal.” (56:43)

• Neurotechnology and Consciousness Control:
  • As the capability to directly affect consciousness grows, so too does the urgent need for philosophical and ethical reflection.

  “Neurotechnology will slowly blend into consciousness technology and we will be able to control states of subjective experience in ever fine grained and reliable manners in the future… we have to ask what is a good state of consciousness?” (59:00)

• Societal Implications:
  • Metzinger warns of potential existential and cultural backlash: resurgence of fundamentalism, or a descent into reductive materialism and hedonism. He calls for collective thought about the kinds of consciousness and lives we want.

Notable Quotes & Memorable Moments

• On the Definition of Consciousness

  “Why does this feel like anything at all? From an inward perspective, how does all this subjective quality in our conscious lives come about?“
  — Thomas Metzinger, 09:30

• On the Self-model

  “The ego, your conscious self, is the mouse pointer on that desktop…that tells the animal, you are here and now, you are this and you are in control. That is how the sense of self emerged.”
  — Thomas Metzinger, 27:14

• On Illusion of Self

  “We don’t need the assumption of a substantial self anymore. We can explain the emergence of self consciousness, but also intelligent behavior, cognition, all these things, without assuming that there is a thing, a self.”
  — Thomas Metzinger, 30:45

• On Virtual Reality & Full-body Illusions

  “In a totally passive condition, you can briefly create this effect of jumping over and identifying with something else. As soon as you start to physically move, you’re locked in the physical body again.”
  — Thomas Metzinger, 45:24

• On Ethics and the Future

  “We have to ask not only what is a good action, but we have to ask what is a good state of consciousness? … What states of consciousness should be illegal in our societies, if any? … What is a good life given all this new knowledge about ourselves and all these new potentials for action?”
  — Thomas Metzinger, 59:00

Important Segment Timestamps

• 03:08 – Metzinger’s background and aim for The Ego Tunnel
• 06:37 – Three major problems in philosophy of mind (mind-body, intentionality, consciousness)
• 12:52 – “The appearance of a world” as working definition of consciousness
• 16:38 – Consciousness as a biological process and its evolutionary function
• 22:33 – Ego Tunnel metaphor and its explanatory value
• 29:26 – The self is a process, not a thing
• 34:40 – Rejection of a non-physical substantial self
• 35:09 – The value of scientifically studying altered states (OBEs, dreams)
• 41:13 – Metzinger’s early professional risk in writing about OBEs; the neuroscience breakthrough with Olaf Blanke
• 42:40 – Rubber hand illusion and the genesis of full-body illusions in VR
• 51:44 – The anchoring of the self-model through constant sensory and motor body feedback
• 56:43 – The “naturalistic turn” and its challenges
• 59:00 – Neurotechnology, normativity, and questions about the “good life”

Final Thoughts

This episode offers an expert yet approachable overview of cutting-edge philosophical and scientific thinking on consciousness and the self. Metzinger’s “Ego Tunnel” metaphor provides a vivid way to understand how the brain’s internal models create the illusion of a self inhabiting a world, and why that illusion, while adaptive, is ultimately fragile and provisional. By tying philosophy to contemporary neuroscience—including groundbreaking research on body-identity illusions and out-of-body experiences—Metzinger lays the groundwork for future ethical reflection on consciousness technologies and the changing human self-concept.

Recommended for:
Anyone interested in consciousness, philosophy of mind, neuroscience, neuroethics, and the future of self-understanding.

For deeper exploration:

• Metzinger, T. (2009). The Ego Tunnel
• Metzinger, T. (2003). Being No One
• Related podcast: BS 188 – Anil Seth, Being You: A New Science of Consciousness