How much do I want to read more? 7/10

His first experiment is somehow fascinating and seems to "prove" what mystics & buddhists said for centuries "you are not your body":
Place a fake hand in front of you, and hide one of your real hand.
Then stimulate both your real hand and the fake hand perfectly in sync.
After a few min, the brain get tricked into thinking the fake hand is yours.
Later he goes further with the whole body.
It means you could "embody" anything. Your feeling of body ownership, or self-awareness would be "brain made". Possibly because it's needed for self-preservation and survival.

Similarly, the amputees having phantom limbs shows that the brain make up his own body's representation.
Amputees obviously notice the difference between what their brain think and what they see. But this same phenomenon applies to everyone.

Now, mystics and buddhists trained their awareness beyond their senses in such a way they could stop their mental and experience reality beyond their brain's representation. If that makes sense.

Some articles to dig deeper into this experiment (I should update my review after actually reading them)

Back to the book:
Metzinger is convinced the world appears to us through our own interpretation. He's very rational and methodical in his pursuit to "understand" some fascinating questions it implies, but he ends up even more puzzled.
Overall, I found some passages to be very valuable / insightful, and others to be very boring.


INTRODUCTION

In this book, I will try to convince you that there is no such thing as a self. Contrary to what most people believe, nobody has ever been or had a self.
When we speak of conscious experience what is the entity having these experiences?
Who is the feeler of your feelings and the dreamer of your dreams? Who is the agent doing the doing, and what is the entity thinking your thoughts? Why is your conscious reality your conscious reality?

THE PHENOMENAL SELF-MODEL

The rubber-hand illusion: A healthy subject experiences an artificial limb as part of her own body:
Both the artificial rubber hand and the invisible hand are stroked repeatedly and synchronously with a probe.

After a certain time (sixty to ninety seconds, in my case), the famous rubber-hand illusion emerges. Suddenly, you experience the rubber hand as your own, and you feel the repeated strokes in this rubber hand. Moreover, you feel a full-blown “virtual arm”—that is, a connection from your shoulder to the fake hand on the table in front of you.

The most interesting feature I noticed when I underwent this experiment was the strange tingling sensation in my shoulder shortly before the onset of the illusion—shortly before, as it were, my “soul arm” or “astral limb” slipped from the invisible physical arm into the rubber hand.

The PSM of Homo sapiens is probably one of nature’s best inventions. It is an efficient way to allow a biological organism to consciously conceive of itself (and others) as a whole.

Most animals are conscious to one degree or another, but their PSM is not the same as ours.
Our evolved type of conscious self-model is unique to the human brain, in that by representing the process of representation itself, we can catch ourselves—as Antonio Damasio would call it—in the act of knowing. We mentally represent ourselves as representational systems, in phenomenological real-time. This ability turned us into thinkers of thoughts and readers of minds, and it allowed biological evolution to explode into cultural evolution. The Ego is an extremely useful instrument—one that has helped us understand one another through empathy and mind-reading. Finally, by allowing us to externalize our minds through cooperation and culture, the Ego has enabled us to form complex societies.

whatever is part of your conscious Ego, is endowed with a feeling of “mineness,” a conscious sense of ownership. It is experienced as your limb, your tactile sensation, your feeling, your body, or your thought.

When I first experienced the rubber-hand illusion, I immediately thought it would be important to see whether this would also work with a whole rubber body or an image of yourself. Could one create a full-body analog of the rubber-hand illusion? Could the entire self be transposed to a location outside of the body?

there are phenomenal states in which people have the robust feeling of being outside their physical body—these are the so-called out-of-body experiences.
Could they be created in the lab?
The answer is Yes.

This is why it is a tunnel: What we see and hear, or what we feel and smell and taste, is only a small fraction of what actually exists out there. Our conscious model of reality is a low-dimensional projection of the inconceivably richer physical reality surrounding and sustaining us. Our sensory organs are limited: They evolved for reasons of survival, not for depicting the enormous wealth and richness of reality in all its unfathomable depth.
Therefore, the ongoing process of conscious experience is not so much an image of reality as a tunnel through reality.

Whenever our brains successfully pursue the ingenious strategy of creating a unified and dynamic inner portrait of reality, we become conscious.
First, our brains generate a world-simulation, so perfect that we do not recognize it as an image in our minds. Then, they generate an inner image of ourselves as a whole. This image includes not only our body and our psychological states but also our relationship to the past and the future, as well as to other conscious beings.
The internal image of the person-as-a-whole is the phenomenal Ego, the “I” or “self ” as it appears in conscious experience; therefore, I use the terms “phenomenal Ego” and “phenomenal self ” interchangeably.

We are not in direct contact with outside reality or with ourselves, but we do have an inner perspective. We can use the word “I.” We live our conscious lives in the Ego Tunnel.

A conscious world-model active in the brain is transparent if the brain has no chance of discovering that it is a model—we look right through it, directly onto the world, as it were.

The Ego, as noted, is simply the content of your PSM at this moment (your bodily sensations, your emotional state, your perceptions, memories, acts of will, thoughts). But it can become the Ego only because you are constitutionally unable to realize that all this is just the content of a simulation in your brain.
It is not reality itself but an image of reality—and a very special one indeed. The Ego is a transparent mental image: You—the physical person as a whole—look right through it. You do not see it. But you see with it. The Ego is a tool for controlling and planning your behavior and for understanding the behavior of others. Whenever the organism needs this tool, the brain activates a PSM. If—as, for instance, in dreamless deep sleep—the tool is not needed anymore, it is turned off.

It must be emphasized that although our brains create the Ego Tunnel, no one lives in this tunnel. We live with it and through it, but there is no little man running things inside our head. The Ego and the Tunnel are evolved representational phenomena, a result of dynamical self-organization on many levels. Ultimately, subjective experience is a biological data format, a highly specific mode of presenting information about the world by letting it appear as if it were an Ego’s knowledge. But no such things as selves exist in the world. A biological organism, as such, is not a self. An Ego is not a self, either, but merely a form of representational content—namely, the content of a transparent self-model activated in the organism’s brain.

What would it mean for an Ego Tunnel to branch out to include other Ego Tunnels? What happens to the Ego Tunnel during the dream state? Can machines possess an artificial form of self-consciousness, and can they develop a proper Ego Tunnel? How do empathy and social cognition work; how can communication take place from one tunnel to the next? Finally, of course, we must ask: Is it possible to leave the Ego Tunnel?

Yes, there is an outside world, and yes, there is an objective reality, but in moving through this world, we constantly apply unconscious filter mechanisms, and in doing so, we unknowingly construct our own individual world, which is our “reality tunnel.” We are never directly in touch with reality as such, because these filters prevent us from seeing the world as it is. The filtering mechanisms are our sensory systems and our brain, the architecture of which we inherited from our biological ancestors, as well as our prior beliefs and implicit assumptions. The construction process is largely invisible; in the end, we see only what our reality tunnel allows us to see, and most of us are completely unaware of this fact.

We don’t create an individual world but only a world-model.
Also, the Ego Tunnel is not about what psychologists call “confirmation bias”—that is, our tendency to notice and assign significance to observations that confirm our beliefs and expectations, while filtering out or rationalizing away observations that do not.
Nor is it true that we can never get out of the tunnel or know anything about the outside world: Knowledge is possible, for instance, through the cooperation and communication of large groups of people—scientific communities that design and test theories, constantly criticize one another, and exchange empirical data and new hypotheses

One question to be addressed is, How can all this take place inside the brain and at the same time create the robust experience of living in a reality that is experienced as an external reality?

right now, as you are reading this book. The robust experience of not being in a tunnel, of being directly and immediately in touch with external reality, is one of the most remarkable features of human consciousness. You even have it during an out-of-body experience.

All evidence now points to the conclusion that phenomenal content is determined locally, not by the environment at all but by internal properties of the brain only.
Moreover, the relevant properties are the same regardless of whether the red rose is there in front of you or merely imagined or dreamed about.
To smell anything it doesn’t even require a nose; in principle it can also be elicited by stimulating the right combination of glomeruli in your olfactory bulb.

The NCC is that set of neurofunctional properties in your brain sufficient to bring about a conscious experience. There is a specific NCC for the redness of the rose you experience, another for the perceptual object (that is, the rose as a whole), and yet another underlying your accompanying feeling of happiness and relaxation.

Why is consciousness subjective?
why a conscious world-model almost invariably has a center: a me, an Ego, an experiencing self. What exactly is the self that has the rubber-hand illusion? What exactly is it that apparently leaves the physical body in an OBE? What exactly is it that is reading these lines right now?


PART ONE - THE CONSCIOUSNESS PROBLEM

THE APPEARANCE OF A WORLD

Consciousness is the appearance of a world.
but in dreamless deep sleep, nothing appears. there is a reality out there. you do not even know that you exist.

Consciousness is a very special phenomenon, because it is part of the world and contains it at the same time.
All our data indicate that consciousness is part of the physical universe and is an evolving biological phenomenon.

This property, as noted, probably distinguishes us from most other animals on this planet: the ability to turn the first-person perspective inward, to explore our emotional states and attend to our cognitive processes.

The evening sky is colorless. The world is not inhabited by colored objects at all. It is just as your physics teacher in high school told you: Out there, in front of your eyes, there is just an ocean of electromagnetic radiation, a wild and raging mixture of different wavelengths. Most of them are invisible to you and can never become part of your conscious model of reality. What is really happening is that the visual system in your brain is drilling a tunnel through this inconceivably rich physical environment.

While we are drinking in all the colors, sounds, and smells—the diverse range of our emotions and sensory perceptions—it’s hard to believe that all of this is merely an internal shadow of something inconceivably richer. But it is.