Nature slapped both theories of consciousness in the face at the same time
2023
A world-class neuroscientist has lost a 25-year-old gamble
The bet is a case of wine
It's one of the deepest mysteries of mankind.
Where does consciousness live in the brain?
His name is Christopher Koch
I used to believe that within 25 years, science would find a neural marker of consciousness.
What happened?
He was at the Science of Consciousness Annual Meeting in 2023
Handed philosopher David Chalmers a bottle of 1978 Madeira
Admit with a wry smile
Things were not as clear as he had imagined
Chalmers takes the drink
He smiled and said something
It is clear that
Things are not clear
Hello
Hello.
I am Wang Lijie
But the story doesn't end there.
The year Koch lost the bet
One of the largest consciousness experiments in history
It is being promoted simultaneously in multiple laboratories around the world
This project is called COGITATE.
Funded by Templeton World Charitable Foundation
It took seven years.
2025
The results are finally out
Posted directly in Nature
This paper does something unprecedented
It brings together two theories that have dominated the science of consciousness for decades
Pull into the same ring
Use the same set of experiments to judge simultaneously
What happened?
Both theories have been substantially challenged
In vernacular
Both overturned
Today's video
I'm going to tell you the story of this paper.
But what I'd rather explore
Is a bigger problem behind this result
Why haven't we been able to find the switch on consciousness?
This failure itself
Are they telling us something profound?
Let's first understand these two theories
The first is called integrated information theory.
English abbreviation IIT
It's by Giulio Tononi at the University of Wisconsin-Madison.
The central proposition of this theory is very bold
It says consciousness is not a function of a certain area of the brain
It's a system's ability to integrate information itself.
Tononi even invented a mathematical symbol to measure it
It's called φ.
The higher the φ value of a system
The greater the degree of information integration
The richer the conscious experience
According to IIT
The central base of consciousness is in the back of the brain
That's the posterior cortex.
Why the back?
Because the posterior cortex contains a large number of densely interconnected neural circuits
The information is highly integrated there.
Forming a complex causal structure
IIT forecast
And it's this continuous synchronized activity in the posterior cortex.
Constitutes the consciousness you are experiencing right now
The second theory is called the global neural workspace theory
English abbreviation GNWT
The concept was first proposed by Bernard Barthes
Later, the French neuroscientist Stanislas Dea
Na developed it into a complete neuroscience model
Its core idea is
And consciousness is a sort of theater spotlight.
The sensory areas in the back of the brain are always processing input.
But most of it runs silently in the background
You don't even realize it.
Only when something is powerful enough to be pushed to the global stage
Broadcast throughout the brain
In particular, the prefrontal cortex participates in the global workspace
You will really realize it
The GNWT has a landmark prediction.
It's called ignition.
What do you mean?
The moment you become truly aware of something
There's a sudden burst of neural activity in the prefrontal cortex.
It's like a match being polished.
And this ignition occurs roughly 200 to 300 milliseconds after the stimulus is present.
Before ignition
And yet information just goes round and round in those sensory areas in the back of the brain.
After ignition
Information was thrust onto the global stage.
You really see it
Did you notice?
There's a very central disagreement between these two theories.
Does consciousness live in the front or the back of the brain?
IIT says behind
And that posterior cortical integration activity is consciousness itself.
GNWT says it's up front.
Ignition broadcasts without prefrontal lobes
There's no real conscious experience.
This is not philosophers arguing on the sofa.
This is a scientific disagreement that experiments can judge
But for decades
Each side does its own experiment
Cite their own evidence
No one can convince anyone
The experimental design you did was good for your theory
The experimental design I did was favorable to my theory
This phenomenon is called confirmation bias in the philosophy of science
How do we break this deadlock?
Someone came up with a genius solution
It's called adversarial collaboration.
Simply put
Bring proponents of both theories to the same table
Plus a bunch of neutral referee scientists
Let's design experiments together
Each side writes down their own predictions
If the result is A.
Explain that my theory is correct
If the result is B.
It means I was wrong.
We then pre-register all of those predictions.
lock
No post-mortem modification allowed
Finally, a neutral third party performs experiments and analyzes the data
The essence of this approach lies in
No one can make up a story after seeing the results
That's what the COGITATE Alliance does.
They recruited 256 subjects
And they're using three state-of-the-art brain imaging technologies.
functional magnetic resonance fMRI
You're looking at blood flow patterns.
High spatial accuracy
Magnetoencephalography MEG
It's the magnetic field.
High time accuracy
And intracranial electroencephalogram iEEG
This is putting electrodes directly into the brain to measure
What's the concept?
This kind of data can only be collected incidentally during surgical monitoring of patients with epilepsy
Extremely precious
Three tools are available at the same time
Simultaneous locking of brain activity in three dimensions: space, time and depth
The precision and scale of this experiment are unprecedented in the history of consciousness science
How do you do that?
Show subjects different types of visual stimuli
Such as faces, objects, letters
The length of each rendering is different
Half a second, a second, a second and a half.
And then we used all three of these tools to measure simultaneously in different areas of the brain.
Activity patterns at different points in time
Here it is.
Look at IIT first
IIT forecast
When you become aware of a visual stimulus
There should be sustained synchronized activity in the posterior cortex.
That is to say
Those circuits in the back should be tightly integrated.
And this synchronization should continue until the stimulus wears off.
What did the experiment find?
The posterior cortex does have a sustained response
Activity in the occipital and lateral temporal lobes does indeed reflect the duration of the stimulation
But the kind of continuous synchronization within the posterior cortex predicted by IIT
Did not appear
There is indeed information in the back.
But there is no IIT maintained between those regions.
The kind of tightly interconnected model required
This directly undermines the core proposition of IIT
The structure of neural networks determines consciousness
And look at GNWT.
GNWT predicts two things
first
When the stimulus wears off
The frontal lobes should have a clear ignition.
second
The prefrontal lobe should be able to represent the full range of visual content that you're aware of in every dimension.
For example, what category and orientation do you see?
What happened?
The first prediction basically failed.
Prefrontal lobe ignition when stimulation disappears
Did not appear under most experimental conditions
The second prediction was also discounted
You do have content-specific activity in the frontal lobes.
It can tell whether you're looking at faces or letters.
But for such details
The frontal lobes can do almost nothing.
This is far from the comprehensive global broadcast that GNWT describes
So you see
Experiments give partial marks to both theories
But it also deducts the most crucial points
IIT says consciousness is back-synced.
Experiments say that synchronization doesn't exist
GNWT says the front of consciousness ignites.
Experiments show that the ignition is often absent
It's a lose-lose situation.
And notice
The paper also points out a sentence in particular
These challenges are not limited to IIT and GNWT.
They also extend to other theories of consciousness that share similar predictions
What do you mean?
So the shockwave didn't just hit two contestants.
All the theories that bet big on posterior cortical synchronization or prefrontal ignition
Have to reassess their foundation
But I want you to stop.
Don't jump to the conclusion that these theories are rubbish
Because this is precisely what makes science most fascinating
Think about it.
Newtonian mechanics was also overturned
But is Newtonian mechanics rubbish?
Not at all.
It's still surprisingly accurate on an everyday scale
Einstein's general theory of relativity overturned Newton's absolute view of spacetime
But Einstein's theory itself is not fully compatible with quantum mechanics to this day
The deepest cracks in physics have yet to be repaired
So you're saying physics failed?
Nope.
Every time an elaborate theory falls apart in front of an experiment
Light leaking from cracks
Often the next breakthrough
And you look at the results.
Will find a very interesting pattern
Consciousness is indeed in the visual cortex.
Ventral temporal lobe and inferior frontal cortex were found
And the prefrontal and early visual areas
There is indeed content-specific synchronization.
That is to say
Consciousness doesn't live in the front, it doesn't live in the back.
It's more of a back-to-front, front-to-back dynamic.
The actual data is far more complex than any theory can draw
Interestingly, 2024
There was also a review paper co-authored by multiple proponents of the theory of consciousness
Published in Neuron, the top journal of neuroscience
This paper acknowledges an important fact
Current theories of consciousness
Including IIT, GNWT, higher-order theory
Cyclic processing theory and predictive processing theory
The controversy between them far outweighs the consensus
Even the most basic questions
What is consciousness and how to identify conscious states
What are the requirements for a qualified theory of consciousness?
No one agreed
What does that mean?
Means the current state of the science of consciousness
This is a little bit like physics a hundred years ago.
Classical physics thought it was finishing the puzzle of the universe.
Only two small dark clouds remain
It turned out that those two dark clouds exploded relativity theory and quantum mechanics
It directly overturned the entire foundation
The science of consciousness may now be standing at a similar crossroads
The old framework is no longer sufficient
But the new framework has not yet been born
And the methodology of COGITATE this adversarial collaboration itself
Perhaps more valuable than any single experimental result
Because it creates a scientific culture of honesty about failure.
You can't just do experiments that work for you.
You have to expose your core projections to the worst possible conditions.
If this method could be extended to other fields of science
The reproducibility crisis caused by many low-quality studies may be alleviated
Which leads me to a deeper question.
We humans have a deep-rooted cognitive habit
We like to find that thing.
What is consciousness?
Where is it?
Give me a place
A mechanism
It's a switch.
We love nouns.
We always turn verbs into nouns.
Turning sight into vision
Transforming thinking into thinking
Turning awareness into consciousness
But the moment you turn consciousness into consciousness
You've made a dangerous assumption
You assume it's a thing
An entity that can be located, measured, locked in a brain region
IIT locks it in the posterior cortex, GNWT.
We shut them up in the prefrontal workspace.
The results of the experiment found that
It doesn't stay in any room entirely
I made a point in the previous video about predictive coding
Consciousness is not a noun
It's a verb.
It's not something you can find.
It's an ongoing event.
I told you that your brain is a predictor.
It creates a controlled illusion about the world all the time
We then calibrate it with sensory data.
But the fabrication process itself
Neither in a single brain region
It's not a single ignition.
It's a prediction and calibration loop that the entire brain runs simultaneously on multiple levels.
The results of this COGITATE experiment
Instead, it confirms this view from the side
Consciousness doesn't live in the back, it doesn't live in the front.
Because consciousness may not be a thing that lives somewhere at all
It's a whole-brain dynamic.
Involving posterior sensory encoding
Classification Integration in the Middle and Attention in the Front
Continuous exchange of information between regulators
You single out any link and say it's consciousness
They all just grabbed the elephant by one leg
Only Knowledge Sect said something similar two thousand years ago
Consciousness is not an entity
It's a process of karmic convergence.
You go to the brain to find the location of consciousness
It's like you're looking for the wind in the wind where the wind lives
The wind doesn't live anywhere
The wind is the air itself.
It's not that science has gone wrong.
Quite the contrary.
This kind of rollover is a sign that science is approaching the truth
When your most well-designed models fall apart in the face of your most rigorous experiments
The crack exposed
It's a blind spot in the way we ask questions.
In 1995, Chalmers posed a question that no one has been able to answer.
It's called the hard problem of consciousness.
He said you could explain how the brain processes information.
How do you create behavior? How do you form memories?
But none of this answers a fundamental question
Why are these physical processes accompanied by subjective experience?
Why doesn't everything run in the dark?
Why is there someone feeling something inside?
This is a problem that, to this day, no theory has been able to get to the heart of.
Maybe we don't need a better theory to answer where consciousness is.
It's about learning to ask a better question.
After Koch loses the bet in 2023
Made another bet with Chalmers on the spot
Bet another 25 years
He said when I was 91
Science must be able to understand the neural mechanism of consciousness
Chalmers is 82 years old
Shake his hand
Say yes.
I'll take it.
This image particularly moved me
Two people who have been struggling with consciousness all their lives
One is the most optimistic neuroscientist.
One is the sharpest philosopher of consciousness.
Nobody convinced anybody.
But no one gave up
They're still willing to gamble for another 25 years
It's not because they know the answer.
It's because they know it's a problem worth a lifetime.
This reverence for the unknown and obsession with the truth
That's what impresses me the most about the scientific spirit.
And maybe that's what consciousness is.
The more you try to catch it
The more it slips through your fingers
It's like you're trying to use a flashlight to illuminate the source of the flashlight itself.
You can only shine anywhere else
But the process of you chasing it itself
It's a process of questioning, rolling over, rebuilding.
That's exactly what consciousness is doing.
You think you are searching for consciousness
But in fact consciousness is the very thing that is being sought.
What do you think?
Do you think science will eventually find the switch on consciousness?
Or is consciousness itself the seeker that can never be found?
I am Wang Lijie
See you next time.