Consciousness Explained

I just finished a great book written by philosopher Daniel Dennett entitled, Consciousness Explained.  The title is ambitious but not misleading, as Dennett forms a theory for how consciousness might actually happen.

If you’re like me, then thinking about how it’s possible for you to experience a sunset or enjoy a symphony isn’t easy.  Dennett argues that many of our intuitions about consciousness trick us into how it actually works. The book is challenging because our intuitions about our inner experiences are so strong that it’s difficult to wrap your head around any possible alternative.

I’d like to summarize the key points in Dennett’s book, but a short article really can’t do justice to the depth of the full book. I suggest anyone who is interested in a theory of how consciousness works to pick up a copy of the book.

Why You Aren’t an Expert on Consciousness

In a recent TED Talk, Daniel Dennett explains why his job can be difficult.  Everyone feels that he or she is an expert on consciousness.  You’ve had first-hand experience with the phenomenon for your entire life, so that gives you a privileged view on the subject. While you might have direct experience with how consciousness seems to you, that doesn’t give you any favored position for saying how consciousness happens.

Hundreds of years ago, our intuitions made it “obvious” that the sun revolved around the earth.  Because, of course, that’s what it looks like.  However, as Eliezer Yudkowsky points out, “What would it look like if the earth did revolve around the sun?”  Of course, the answer is, it would look exactly the way it looks now.  It’s good to watch our intuitions, but also not to follow them blindly, as that can lead us to roadblocks in understanding.

Consciousness isn’t an “Emergent” Phenomenon

Consciousness is often explained as being an “emergent” phenomenon of complex computing.  As Eliezer explains again, this really doesn’t explain anything.  Using the word “emergent” may sound like a scientific definition, but it does the same job as the word “magical”.  Instead of offering new understanding it’s merely a wave of the hand explaining away something we don’t understand. If you tell yourself consciousness is a “magical” phenomenon, it sounds sillier, but it has the same impact on deeper understanding.

Descartes’ Dualism and the Cartesian Theater

Dennett begins the book with a familiar perspective, Descartes’ dualism.  Descartes was the famous philosopher who uttered “Cogito, ergo sum”, or “I think, therefore I am.” Descartes also had a model of consciousness which depended on the universe being made of two ontologically different sorts of stuff, matter and mind.

According to Descartes, this mind stuff was linked to the matter stuff through the pineal gland in the brain.  This was where he presumed that it all came together and consciousness happened.  This place where mind meets brain is referred to as the Cartesian Theater.  Since our conscious experience seems very much like watching (and participating in) a theater.

There are many problems with dualism (violating the currently understood laws of physics is just one) which make it unattractive to philosophers and scientists for understanding the world.  However, as Dennett makes clear in the book, the ghost of dualism and the Cartesian Theater are so intuitively comfortable that many strictly materialistic scientists fall under it’s spell.

There is No Theater

Dennett’s model of consciousness he calls the Multiple Drafts model.  In this model, there is no theater.  There is no single anatomical place in the brain where all the sounds, smells and thoughts converge together.  Instead, consciousness is the result of many independent processes each writing and rewriting the ongoing narrative of conscious life.

Dennett uses many different neurological and psychological experiments to justify his counterintuitive perspective.  Anatomically, it appears, that the brain has no headquarters.  It seems as if the activities of consciousness aren’t localized in one part of the brain, but spread around the brain, often amongst unconscious processes.

The ghost of the Cartesian Theater still haunts many experts in the field, according to Dennett.  As one example, there has been extensive research on the topic of how hearing is processed in the brain, but relatively little research on how speaking is formed (which is half of communication).  Dennett believes that this is because researchers are struggling to find an “initiating point” where speech acts originate.  And since, according to his view, there is no theater where all consciousness begins, this single point is impossible to find.

Consciousness isn’t in the Hardware…

Instead of being in a single location, Dennett imagines that consciousness is better described as a virtual machine.  A virtual machine, for those who have studied computers, is basically a system built on top of a different system.  The word processing software I’m using now is a type of machine, responding to keystrokes and button clicks to form words on a screen.  However, it is only a virtual machine, as the hardware it is built on is a completely different system of 1’s and 0’s.

Reseach in artificial intelligence has lead to computer scientists making simple brainlike, parallel computers off of linear, digital computers.  Dennett believes consciousness could be an opposite process.  It is a linear, sequential machine built on top of a massively parallel structure such as the brain.  This machine is the reason people have the intuitive sense of events happening in a linear fashion, even though the processing to create them is happening simultaneously in the brain.

Thought Experiments

Dennett attacks several thought experiments proposed by other authors that lead people to make incorrect observations about the nature of consciousness.  Although he takes down several in his book, two of the big ones are often known as “Mary the Color Scientist” and the “Chinese Room” thought experiments.

Mary the Color Scientist

The first experiment is set to show that the intrinsic qualities of our experience (known as qualia) exist separately from the neural connections of our brains.  This is a popular view because it feels so obvious: “How can the blueness of the color blue just be from firing neurons in my brain?” The thought experiment typically goes like this:

Imagine Mary the color scientist was born in a black and white room, and only had a black and white television to view the world through.  Assuming there were no mirrors or reflective surfaces in the room, we would assume that Mary had no access to any color her entire life.

She studies color and learns every physical fact about color.  One day her captors decide to free her and let her back into the colored world, at which point, Mary sees the color yellow.  Does Mary learn a new fact when she enters the world?

The problem with this thought experiment, according to Dennett, is that it misleads you with the sentence, “She learns every physical fact about color”.  This is deceptive because the thinker of the thought experiment is invited to make an impossible imagination, proceeds to ignore it, and then creates a false assumption about the experiment.

“Knowing every physical fact about color” is different than, “knowing a lot about color.”  The thought experiment invites you to do the first, but it’s only possible for you to do the second.  If you truly knew every fact about color you wouldn’t just know the properties of light, but how it reacts, in detail, with your brain.  This level of knowledge isn’t impossible, but it is far beyond our current understanding of color and perhaps will be forever.

Dennett uses this to argue that if Mary really did know everything about color, she would be able to anticipate her own reaction to seeing the color yellow.  By entirely anticipating her entire cognitive simulation and response to the stimulus, she would know what yellow is like.

The Chinese Room

The second thought experiment Dennett attacks in his book is John Searle’s infamous Chinese Room thought experiment.  This thought experiment is designed to show that no matter how sophisticated a robot could become, it could never be conscious.  Unfortunately, this thought experiment makes the same mistake as the preceding one, by asking the thinker to make an impossible imagination which is ignored, leading to an incorrect conclusion.

The thought experiment typically goes like this:

A computer program has been developed to interpret and speak Chinese.  It is sophisticated enough that it can fool an ordinary Chinese person into believing it is conscious, via something like an internet messaging system.

In fact, the program isn’t run on a computer, but is actually run by a man inside of a room.  He has a detailed set of instructions for how to run the computer, this involves taking the input from the computer, and moving the symbols around according to the instructions until it results in the output.

Where is the consciousness?

As Searle notes, the man operating the program isn’t conscious of any Chinese.  He wouldn’t “know” Chinese like a native speaker, he is just following simpleminded instructions.  Similarly, all the symbols and instructions are inanimate objects.  So where, is the thinking?

Dennett notes the problem with this approach is that it invites the thinker to imagine a machine that can fool someone into believing it is conscious, but doesn’t invite them to think in any considerable depth.  The level of detail required to run this program would mean that, even for a single sentence and response, the man operating the room would likely need to perform billions of operations with the symbol over hundreds of billions of pieces of memory.  The reader can’t imagine this, so instead imagines a relatively simple system and declares it to be not conscious.

In the Chinese Room, it isn’t the man who is conscious (just like your individual neurons aren’t conscious), but the room itself.  If the system were complex enough to fool a person into believing it is conscious, the program would be so sophisticated that the system would be consciousness.

Consciousness Explained

I’ve just touched on a few points in the book, but it goes into far more detail.  The book is subtly profound as even after you understand the analogies Dennett uses to describe a conscious process, you are still trying to wrap your head around their implications.

Is consciousness just a mystery that is better left unknown?  Although learning more about a phenomenon strips it of some of its mystique, it adds understanding.  That understanding gives us power and opens the way for new, unsolved mysteries.

Getting a grasp on how your inner mental life might come about isn’t just a philosophical quest with no bearing on current life.  Understanding it is key in an age where technological advancements are questioning our identity.  If we don’t figure out what makes us what we are, then we will be hopelessly lost in an era where we may be losing our position as the most intelligent point in our universe.

A famous physicist once remarked that, “I never think of beauty when I’m looking for a solution.  But if I find a solution that isn’t beautiful, I know it isn’t correct.” Dennett’s theory may not be obvious, but I think it is beautiful once you wrap your head around it.

  • J.D. Meier

    Great write up.

    It reminds me of the saying, “all models are wrong, but some are useful.”

    Useful is a great test and I measure against effectiveness.

  • Liz

    Consciousness is undefinable, yet it’s qualities can be known. Consciousness, is awareness, is self-growing, is continual and without end and undiscriminating. Consciousness is the ability to know itself in as many ways as is possible. Consciousness is awareness of expansion through recognizing itself as the agent of expansion. As consciousness manifests itself in physical properties, ie brain matter, rocks, neurons, wood, concrete and all possible variations of stuff, it also recognizes itself without physical boundaries. It just is an awareness non-localized and growing and is not dependent on the container through which is flows and experiences itself.

  • Nick Egrotes

    i prefer to read your ideas than the boo itself

    is meaningless at the moment to explain consciousness, we are just waiting the neuroscience to locate and explain it-in near future i hope-

    Dennett’s theory, is just another theory, not a ny truth

    bye bye

  • Nick Egrotes

    hello again,

    consciousness indeed, is becoming real challenge for science in general,

    of course is not “magic”, i agree with you, still big enigma though


  • david thurman

    “Instead of being in a single location, Dennett imagines that consciousness is better described as a virtual machine”

    This is where dennett stumbles into his own Cartesian theater. The machine metaphor is directly linked to a correspondence way of looking at the brain. This very much reductionist view is fairly dated although I would say it’s the pop view of the brain and really is sort of silly. The illusion is that somehow we can wrap around on ourselves in some simplistic clear defining reductionist way is well simply Cartesian theater looking at Cartesian theater. Our emotions play a key role so a machine model is not going to work very well. I think the move towards a metaphor of nonlinear dynamic system is much more accurate, and I would say Alva Noe is giving us a much more modern and accurate description of consciousness than Dennett. We will never Get around on ourselves so to speak, but we can understand ourselves and i think through that understanding, find our links in who we are in relationship the larger framework that surrounds us. Dennett, he’s a boomer like me, sort of old and tired, has some good insights, I love the Cartesian theater description very nice, It’s already been said thousands of years ago in many if not most religious texts.

  • Gil Gaudia

    While you have done a fine job in summarizing Dennett’s position, I still am unable to imagine who is in control of my thoughts–other than the simplisticly naive little me floating around inside my cranium. When I attempt to consider a mechanistic explanation of consciousness it always comes back to who puts the final stamp on the thought. I know there can be no interaction between non-physical and physical phenomena, yet I am unable to escape the mind-body dualism. I’m an atheist who is imprisoned by a “feeling” that someone (me) is inside my head looking out at the world.

    Thanks for trying.

  • Scott Young


    Yes, our intuitions make it difficult to envision a mechanistic consciousness. However, Dennett does a much better job than I do of reconciling intuition with current neurological theory.


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    Yes, our intuitions make it difficult to envision a mechanistic consciousness. However, Dennett does a much better job than I do of reconciling intuition with current neurological theory.