Thursday, July 02, 2009

Metzinger: A tour of the ego tunnel

Metzinger's "The Ego Tunnel" - Abstracted Chapter Two - A tour of the tunnel
(This chapter has really fascinating ideas)

1- The One-World problem: the unity of consciousness.
2- The Now Problem - the appearance of a lived moment
3-The Reality Problem - why you were born as a naive realist
4-The Ineffability Problem - what we will never be able to talk about
5-The Evolution Problem - what consciousness was good for
6-The Who Problem - what is the entity that has conscious experience

1- The One-World problem: the unity of consciousness.

What binds things together in a comprehensive, simultaneous whole? In apperceptive agnosia, no coherent visual model emerges on the level of conscious experience, despite the fact that all the patient’s low-level visual processes are intact. An intact visual field is perceived, but not its content.

To sum up, it would seem that feature-binding occurs when the widely distributed neurons that represent the reflection of light, the surface properties, and the feel of the device you are using to read at this moment start dancing together, firing at the same time. This rhythmic firing pattern creates a coherent cloud in your brain, a network of neurons representing a single object for you at a particular moment. Holding it all together is coherence in time. Binding is achieved in the temporal dimension. The unity of consciousness is thus seen to be a dynamic property of the human brain. It spans many levels of organization, it self-organizes over time, and it constantly seeks an optimal balance between the parts and the whole as they gradually unfold. It shows up on the EEG as a slowly evolving global property, and, as demonstrated by meditators, it can be cultivated and explored from the inside, from the first-person perspective.

2- The Now Problem - the appearance of a lived moment

One essential function of consciousness is to help an organism stay in touch with the immediate present - and properties in the environment that may change fast and unpredictably...Presence is a necessary condition for conscious experience. If the brain could solve the One-World Prolem but not the Now Problem, a world could not appear to you. In a deep sense, appearance is simply presence, and the subjective sense of temporal immediacy is the definition of an internal space of time. There is an upper limit to what you can consciously experience as taking place in a single moment: It is almost impossible to experience a musical motif, a rhythmic piece of poetry, or a complex thought that lasts for more than three seconds as a unified temporal gestalt...the sense of presence is an internal phenomenon, created by the human brain. Not only are there no colors out there, but there is also no present moment. Physical time flows continuously...neuroscience tells us that we are never in touch with the present, because neural information-processing itself takes time. Signals take time to travel from your sensory organs to your brain and be processed and transformed...the moving window of the conscious now successfully bundles perception, cognition, and conscious will in a way that selects just the right parameters of interaction with the physical work, in environments like those in which our ancestors fought for is a form of knowledge about what will work with this kind of body and these kinds of eyes, ears, and limbs.

3 - The Reality Problem - why you were born as a naive realist

The pivotal question is how to get from a world-model and a Now-model to exactly what you have as you are reading this: the presence of a world...these models active in the brain are transparent if the brain has no chance of discovering that they are models. ..The brain creates what are called higher order representations - if the first-order process creating the seen object, the book in your hands - integrates its information in a smaller time-window than the second order process (namely, the attention you are directing at this new inner model), then the integration process on the first-order level will itself become transparent...Transparency is not so much a question of the speed of information-processing as of the speed of different types of processing (such as attention and visual perception) relative to each other. The binding of the model of your current reading device with the rest of your experience space, optimized over millions of years, is so fast and reliable that you never notice its existence. It makes your brain invisible to itself. You are in contact only with it content; you never see the representation as such: there you have the illusion of being directly in contact with the world.. you become a naive realist, thinking to be in touch with an observer-independent reality.

The notion of metabolic price is a useful concept. To develop a new cognitive capacity, the brain must pay a metabolic price, if a biological organisms want to develop a conscious self or think in concepts, then this new level of mental complexity must be sustainable. It requires additional neural hardware that requires fuel. Any theory of consciousness must reveal how it paid for itself...This evolutionary perspective helps solve the problem of naive realism.

Our ancestors did not need to know that a bear-representation was currently active in their brains or that they were currently attending to an internal state representing a slowly approaching wolf...All they needed to know was “Bear over there!” or “Wolf approaching from the left!” Knowing that all of this was just a model of the world and of the Now was not necessary for survival. This additional kind of knowledge would have required the formation of what philosophers call meta-representations, or images about other images, thoughts about thoughts. It would have required additional hardware in the brain and more fuel.

Thus, the answer to the question of why our conscious representations of the world are transparent - why we are constitutionally unable to recognize them as representation - and why this proved a viable, stable, strategy for survival and procreation probably is that the formation of meta-representations would not have been cost-efficient: It would have been too expensive in terms of the additional sugar we would have had to find in our environment.

Consciousness is the space of attentional agency, that set of information currently active in our brains to which we can deliberately direct our high level attention. Low level attention is automatic and can be triggered by entirely unconscious events. .. most things we’re aware of are on the fringe of our consciousness and not in its focus. But whatever is available for deliberately directed attention is what is consciously experienced...we are constitutionally unable to apprehend the earlier processing stages.

That is why the walls of the tunnel are impenetrable for us: Even if we believe that something is just an internal construct, we can experience it only as given and never as constructed. We would be overwhelmed if we could apprehend earlier processing stages.

A minimalist concept of consciousness - or how the brain moves from an internal world-model and internal Now-model to the full-blown appearance of a world. If the system in which these models are constructed is constitutionally unable to recognize both the world-model and the experience of the present as models, as only internal constructions, then the system will of necessity generate a reality tunnel. It will have the experience of being in immediate contact with a single, unified world in a single Now, a world appears... the global neural correlate of consciousness (GNCC) will be a dynamic brain state exhibiting large-scale coherence. (Metzinger predicts it will be understood within 50 years).

4 - The Ineffability Problem - what we will never be able to talk about

We are much better at discriminating perceptual values than we are at identifying or recognizing them. For this section, see the May 22, 2009 mindblog posting.

5-The Evolution Problem - what consciousness was good for

There are many potential candidate functions of consciousness: goal hierarchies and long-term plans, enhancement of social coordination,... a long list. A useful idea is of the Global workspace: that subset of active information in the brain that requires monitoring because it’s not clear which of your mental capacities you will need to access next...

Consciousness as a new kind of virtual organ, unlike permanent hardware of liver, kidney, or heart..., that forms for a certain time when needed (like desire, courage, anger, or an immune response)...a new computational strategy, a consciousness tunnel, makes classes of facts globally available and allows attending, flexible reacting, within context.... ‘reality generation’ allowed animals to represent explicitly the fact the something is actually the case, the world is present. (conscious color gives information about nutritional value, red berries among green leaves, empathy gives information about emotional state of conspecifics). Only homo sapiens (and higher apes?) have evolved the additional ability to run offline simulations in the mind, experiencing some things are ‘real’ and other elements of our tunnel as mere thoughts about the world, representing that we are representational systems. Old things in the evolution of consciousness are ultrafast and reliable (like qualities of sensory experience) and transparent: abstract conscious thought is not, it is slow and unreliable, experienced as ‘made.’

6-The Who Problem - what is the entity that has conscious experience

A successful theory of consciousness must match first person phenomenal content to third-person brain content, inner perspective of experiencing self with outside perspective of science... It is likely that consciousness is epistemically irreducible... one reality, one kind of fact, but two kinds of knowledge: first-person knowledge and third-person knowledge, that never can be conflated.

The existence of an experiencing self may not be a necessary component of consciousness... in Cotard’s syndrome, patients sometimes stop using first person pronoun, and claim that they do not really exist. Mystics report deep spiritual experiences in which no ‘self’ exists. Many of the simpler organisms may have a consciousness tunnel with nobody living in it. The need is to understand how in evolution the consciousness tunnel turned into an Ego Tunnel, the experience of being ‘someone’ in a centered model of reality.


  1. All well and good, and fascinating stuff, but I think the notion that there is an actual boundary that is crossed--thus delegating something as concsious--is wrong. There is always a meta-process. So the human brain has more.

    I know we humans like to label everything as "self vs other", or in this case "conscious vs. not", as a matter of utility (and survival), but isn't it more realistic to ask "how conscious" rather than "is it conscious"? What is "simulation" other than feed-forward process control at a higher level of abstraction?

  2. Anonymous1:18 PM

    "but isn't more realistic tos "how conscious" rather than "is it conscous?" Be careful of falling into the judgement trap of more or less.

  3. Anonymous4:23 AM

    Excellent interpretation and summary of Metzinger's book. I appreciate your clear and penetrating account! Thank you!