Robert Blum Website

Robert L. Blum, MD, PhD

The Mystery of Consciousness: Introduction

Consciousness is perhaps the most fundamental unsolved problem in science.

Look at what you are experiencing at this moment.

You are aware of your body, perhaps sitting in a chair, staring at a computer screen.

As you read my words every few moments a competing emotion or sensation flicks across the screen of your consciousness and distracts your attention. And, this you are also aware of. Your eyes and attention flick back and forth between the picture below and the words here.

Or consider this - you, eating a particularly good orange, savoring its sweetness,

its texture, the juice flowing onto your tongue and lips; or this - conversing with friends, watching their faces, delighting in the dialogue but aware of subtle rippling of your emotions as you react to their remarks and weigh comments that you consider making.

This is the most fundamental aspect of the human experience - conscious awareness of self and the world around us: an external world filled with colors, sounds, and textures and an internal world full of feelings and emotions.

Icelandic landscape

Our capacity to do this defines the human experience. We do it; mice to a lesser extent;

fish, lesser still; trees – I say not; rocks, robots, and the internet - not at all (or so we surmise).

(The wonderful Icelandic landscape above is by Nathan Myhrvold, former CTO of Microsoft.)

Understanding consciousness was my holy grail when I was in my youth at MIT

and in medical school. How does it work? Can it be understood by simply knowing enough neurobiology?
Can it ever be designed into, say, robots? Or, are robots and other AI projects
destined forever to be fancy clockwork machines devoid of feelings, vision, and wisdom.

(David Gelernter of Yale Computer Science says “robots are just clockwork.”)
Also, might their critical lack of feelings and compassion make it dangerous to build them?

Obtaining a true and complete understanding of consciousness is critically important to a number of enterprises. First, it would revolutionize psychology and psychiatry by placing them on firm neuroscientific ground. Second, it would advance the age-old dictum to "know thyself." What could be more fundamental than knowing who you really are?

Third, it might finally settle key scientific questions concerning the real nature of the subjective universe
(the world as experienced by each of us) as opposed to the objective world of atoms and physical forces.

Fourth, it might portend an era of consciousness engineering in which we might (if we chose)
redesign our conscious selves (or our artifacts) to be more powerful, more intelligent,
more broadly integrated, more world-encompassing, and hence, wiser and more compassionate.
(Consciousness was the subject of my recent San Francisco Bay Area AI colloquium shown here.)

Of note, one of the most prominent consciousness researchers was Francis Crick,

Nobel laureate and co-discoverer of DNA. Crick devoted the last thirty years of his career
to trying to discover the basis of consciousness, having switched from molecular biology to neurobiology.

At age 78 in 1994 Professor Crick published The Astounding Hypothesis, which relates

his general framework for investigating consciousness. In the very first sentence of the book he

states …

“The Astonishing Hypothesis is that “You,” your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. As Lewis Carroll’s

Alice might have phrased it: “You’re nothing but a pack of neurons.”

Now, the Astonishing Hypothesis – let’s called it AH! – may strike you as it struck me –

not so astonishing or maybe even obviously true. What else could it be? We think and feel

with our brains, which are made of a vast assembly of neurons. What’s so astonishing about that?

I hope you’re in that camp, because, if you’re not, I’m not going to address your beliefs

in this, or possibly any, of my essays - except right here.

Here is the top-level argument that consciousness, thinking, and feeling are mediated by

brains and only by brains (and NOT say a divine spirit that comes to rest in you when you are born and that floats away when you die.) 1) In one minute by injecting an anesthetic into the appropriate nerves I can make a painful finger, hand, arm, or foot totally disappear from awareness. 2) In less than one minute by injecting an anesthetic intravenously I can take you from fully alert to comatose. 3) In patients injured by stroke, head trauma, or cancer there is a tight correspondence between the part of the brain that’s injured and a change in the person’s capabilities. 4) There is a reliable correspondence between brain waves (eeg) and state of consciousness (alertness, deep sleep, dreaming, coma). 5) At death the brain waves cease.

6) There is a reliable spatial and temporal correspondence between various abilities, images, and thoughts with highly specific regions of the brain with fMRI and other imaging methods.

Now, you might believe that consciousness exists prior to conception or after death.
Many people and religions espouse that view. Even some transpersonal psychologists
think that’s the case. Or, you might believe in panpsychism – consciousness is everywhere
in the Universe, including the trees, rocks, water, and stars. Again, you would have
lots of company, including New Age folks and others of a spiritual bent. (I am also
of a spiritual bent, but not in the sense of free-floating apparitions - more in the sense of
a Universe that is inherently generative a la Thomas Berry or Teilhard de Chardin.)

Until the mechanism of consciousness is finally elucidated, who’s to stay – you might argue – that a rock is not conscious or your computer is not conscious or that your immortal soul survives the death of your body.

Yes, those propositions might be true, but as scientists we are committed to reasoning based upon evidence. The evidence that I summarized above, as well as millions of neuroscience studies confirm the Astonishing Hypothesis – you’re a pack of neurons!

Get used to it! (but see below - you are also a soul!)

Please note, however, that I don’t really mean just a pack of neurons. 1) The fact that

the nervous system is intimately connected to the body and that the body is situated in the world is hugely important. 2) The phrase pack of neurons is misleading – the actual number is one hundred billion neurons with one quadrillion synapses (average of 10,000 per neuron).3) The notion of a synapse as just an on/ off switch is obsolete. According to Stanford neuroscientist Stephen Smith, each synapse is more like an entire microcomputer with a kilobit of memory. So, the brain is vastly more complex than even the entire internet.

Pack of Neurons vs Soul: Emergence

And now for an almost 180 degree shift ...
When is a pack of neurons not a pack of neurons?
When it's a soul! (Here for the moment the equation is soul = consciousness .)

Might that network of neurons be so vast and so elaborate that it would be
a gross conceptual error to identify the whole with the sum of its parts.
Yes! Consciousness is exactly that - a property that somehow EMERGES
from the operation of many parts and yet is quite distinct from them.

EMERGENCE is found many times in science
and in the history of the Universe. It most obviously occurs when atoms
bind together to form molecules. There is nothing in the properties of the gases
hydrogen and oxygen that would in any way suggest what the properties
of water might be. Water is completely different from the sum of its parts
despite being composed of only three atoms. Water is quite complex. Even water
has emergent properties as its phase changes from ice to water to steam.
It was only in 2007 that the properties of water were finally modeled.
Table salt - sodium chloride - is an even more dramatic example,
composed of one atom each of an explosive metal and a deadly gas

In more complex systems such as living matter the emergent properties
are even more unpredictable. While it is possible to model some aspects of
living systems with computers, modeling entire systems is not possible.
One well known example is the protein-folding problem. Every living organism
is made from proteins - long strings of amino acids. However, proteins can only work
if they are folded into precise 3D configurations (which they do themselves).
This process is so complex that it can only be modeled for small proteins
by the world's most powerful computers. Modeling the complete
function of an entire organism - like a bacterium - is just not possible.

When it comes to organisms with nervous systems, the complexity
that results from the multi-way interaction of billions of components is far
beyond current computational feasibility. As an example, the 1 millimeter
round worm, Caenorhabditis Elegans, has only 302 neurons and 6000 synapses
in its transparent body. The structure of its nervous system has been known
for two decades, and yet it has proven impossible to model and predict its behavior.

With human brains it is clear that multi-way, time-varying interactions
among its quadrillion synapses are the norm. If emergence occurs in a
water molecule with its three atoms, the notion that consciousness = soul
can be reduced to "just a pack of neurons" seems exceedingly unlikely.
That does not mean that neuroscience is not making progress.
It does mean that we have a long ways to go.

Zombie vs Sentient: Do Atoms Have Feelings?

The real question, of course, is “how does consciousness emanate from the workings of a pack of neurons?”
Until we show how it actually happens, some skepticism about the validity of the AH! may be justified.

Suppose neuron A fires neuron B, which, in turn, fires neuron C, etc. So what!
How and where does the actual seeing and feeling occur? Where does consciousness arise?
Entire collections of neurons in our bodies can fire, and we are completely unaware of them.
The thirty billion neurons in the cerebellum produce no imprint on consciousness whatsoever.
Similarly, millions of neurons may fire in the spinal cord or the gut of which we are unaware.

What is the purpose of consciousness? What does it do?
It is easy to imagine building a robot that does some or perhaps all of what we do
but which is totally unconscious. That is, it works but there is "no one home."
It feels like nothing to be that robot. That is David Gelernter's position,
and it is also mine. Enlightenment scientist Leibniz (co-inventor of calculus)
posited the same thing in 1714.

"Suppose we had a windmill whose construction enabled it to think, to sense,
and to have perceptions. Upon visiting this machine and walking around inside,
one would find only parts pushing one another and never anything to explain perception."

Philosophers regularly discuss the possibility of a zombie - a human being that
does everything we do but who completely lacks sentience. The zombie does not see, hear, feel,
or have any emotions but otherwise can do everything we do. One can imagine building that sort of robot -
but a robot that actually sees and feels? How does one do that?

Furthermore, what exactly is consciousness - actual seeing, actual feeling?
Is it made out of atoms or electrochemical forces or is it something entirely different?
Philosopher David Chalmers and neuroscientist Giulio Tononi say consciousness = information,
but what is that? Does that mean my computer might be conscious or my thermostat?

I briefly addressed the beliefs of those of a religious bent above.

However, more interesting to me than the religious stance is the stance and skepticism of

some of my friends who are engineers and scientists (not in brain science).

Their question is “how do we even know that consciousness is real?”
I know that I am conscious, but how can I ever show that you are conscious?

My scientist friends may also take the following tack.
Since consciousness is forever subjective, and therefore not objectively verifiable,
it cannot be attacked scientifically.

In the strictest sense they may be right. If my own consciousness is something
that only I can observe, then how can it ever be verified or measured?

My hunch is that as the neural correlates of consciousness become known
in greater detail the issue will become clearer. Meanwhile it seems to me that
1) the world of consciousness is all we really know directly; 2) that any description of the world
that leaves it out (as does the current standard model of physics) is glaringly incomplete;
and 3) that this is at least as important a scientific problem as current attempts at grand unification of forces.
Our attempts to engineer consciousness into machines will be stymied until its nature is understood.

Meanwhile, let’s accept Crick’s Astonishing Hypothesis (AH!) for now.

Armed with just the AH! there is a hugely important corollary:

Subjective Reality is All There Really Is! (SRIATRI)

If everything we know, think, and feel IS due to the precise state of our brain,
then we have no direct contact with the world outside. Instead, we are just information processing machines
that get our knowledge of the outside world in just the same way that robots, computers,
and other machines do – from an array of sensors.

Now, just like the AH!, the SRIATRI corollary may strike you as being just as trivial
and self-evident. However, my sense of SRIATRI is that it is deeply profound.

In the movie The Matrix, the hero, Neo, takes the red pill, and wakes up
to the absolute tangible, first hand knowledge that his entire life and all his beliefs
have been a computer- induced hallucination. That is – in a milder form – the actual state of affairs in the real world.

My perception of myself is that I am staring out at the world through my eyes,
looking at a world filled with colored objects. In reality, I don’t exist as a unitary agent,
the colored objects of the world are phantasmagoras, and I (whatever that is) am utterly unconscious
of the output of my retinal ganglion cells that form my one million fiber optic nerves.
The whole thing is an elaborately engineered illusion. Instead of the body in a vat plugged into the Matrix,
what we actually have is a brain, floating in cerebrospinal fluid in a totally dark, calcified box
connected to a sensor array by a collection of cables (the spinal cord and cranial nerves).
Of course, the resulting hallucination has great correspondence with the outside world,
otherwise none of our ancestors would have survived to reproduce.

The hallucinatory life that Neo normally leads (the blue pill / normal reality) is what

cognitive scientists and philosophers call NAÏVE REALISM . Naïve realism is
the patently false belief that “the way I experience the world is the way it actually is.” It is NOT!

Science tells us that what's actually out there is a collection of atoms and photons
electromagnetically interacting. On the other hand I experience a world of solid objects
with my eyes and hands. Not only do we not experience the atoms and photons, the sight and touch of

solid objects is different for each of us. And if that is the case, then each of our experiences
of intangible objects and events – what it’s like to live life, what’s important in the world,
what we think of other people and places is hugely subjective.
So, every shred of experience is SUBJECTIVE. Naive realism is out!
In fact, it’s dangerously naive (less so if you're a child, more so if you possess weapons of mass destruction.)

Now, nobody who has studied neurobiology accepts naive realism; so rejecting it is not new.
Psychologists and neurobiologists accept that the brain constructs and stores
a WORLDVIEW which is a map of the organism's external reality
and that we live and die by that worldview. (and, that the map is not the same as the territory.)

SRIATRI means nobody is in touch with absolute reality. It’s not possible.
The best any of us can do is to plug into consensus reality – the world described
by our culture at large, including all its scientists, teachers, opinion leaders, politicians,
writers, artists, and media people. Of course, consensus reality is constantly changing and evolving.
(My favorite examples are the big paradigm shifts like those described by Thomas Kuhn,
for example, theory of evolution, quantum mechanics, plate tectonics, the role of asteroid impact in evolution, etc.)

By the way, the world’s population is about 6.8 billion. My guess is that well over 6 billion are naïve realists.
So, there is a lot of work for teachers in every country on earth. That is why the internet, Wikipedia,
and One-Laptop-Per-Child are so important.

(I just caught myself in an error that I must immediately clarify.
Naïve realism and global consciousness are really about states of knowledge
and not about consciousness in the sense of the Icelandic waterfall above.
Those are two quite distinct uses of the word, and it is really the sense that pertains
to direct vision or hearing that I will be predominantly addressing, not its meaning
as in the phrase “higher consciousness.”

Here, I’ve just introduced the importance of the consciousness problem,
that is, the mind/body problem. The real question is how precisely does it work? How does

the conscious or subjective world arise from the brain? That is what I shall address in the accompanying essays.

For those who can’t stand the suspense, my essays in the coming weeks
will review work by Professors Christof Koch, Thomas Metzinger, Bernard Baars,
Giulio Tononi and other top researchers. Topics will include the quest for the
neural correlates of consciousness, the illusion of self, the biologic function or purpose of consciousness,
and methods for quantifying consciousness.