Cultural Evolution · The Human Mind and Brain

Summary of From “Bacteria to Bach and Back” by Daniel Dennett

This is a summary of Daniel Dennett’s book From Bacteria to Bach: The Evolution of Minds. Copyright  2017.

In my opinion this is one of the most important recent books on the human mind.  Dennett has been working on how the human mind works and what human consciousness is, in relation to  both genetic and cultural evolution for his entire  career, which has been a long and fruitful one. This book is probably the apex of those long years of thinking about minds and evolution.  I think this book is possibly the beginning of some real answers to the most vexing and mysterious questions scientists have been asking for a long time. Questions like what exactly is human consciousness, how are genetic and cultural evolution related and what does this have to do with the human brain and with human success on the earth and why humans are the way they are.

This is a difficult and a long book, and this summary is also long and difficult.  In spite of this, I think the book is well worth reading and I highly recommend reading the book itself.  And writing this summary has been very valuable for me.    Actually I have written this summary mostly for my understanding of Dennett’s book as as a way to remember the salient points.  If anyone else finds it useful, I’m glad.  But no guarantees.

I think this book is also a good example of a somewhat recent trend: The philosopher as scientist and visa versa.  Dennett is a philosopher by profession but he spends much of his time talking to and being educated by working scientists and is very conversant about contemporary science.  Philip Kitchner is another philosopher who writes a lot about  about science.   And then there are scientists like Francis Crick, Richard Dawkins, Steven Pinker, Lisa Feldman, Robert Sapolsky, Joseph Heinrich, Josuha Greene and Peter Atkins, and Lee Smolin who spent a lot of their time written books about being and reality and time and essence, traditionally the topics of philosophy.  And I could probably name fifty more scientists who have written what are basically books about philosophy.   I guess what I am saying is that philosophy (except for analytical philosophy) seems to be gradually turning into science and that scientists are beginning taking the place of all the philosophers who used to speculate about reality.  As this happens,  I think traditional philosophers who still refuse to accept science as the new philosophy, are losing ground.

What follows is a summary of Daniel Dennett’s book From Bacteria to Bach and Back, written as I read the book.  This is not a book review or a commentary on the book.  This summary is an ongoing project which I hope to complete by the end of May, 2017.

Dennett begins the book by saying he is an amateur when it comes to cognitive science but he has had a lot of instruction over the years from the experts. So he claims this book to be merely a sketch, a brief outline,  about how minds actually evolve. In spite of this he says that the book is the  backbone of the best scientific theory to date on how our minds came into existence.  

Dennett  also says he has described the so-called “magic” of our minds without any magic at all.   He says that some of the things he says will challenge our innate beliefs and that we will have to abandon some of our intuitions and ideas that we consider obvious truths.  He says we will have to give up a lot our old comfortable ideas to follow him in this book. He says that actually  he really isn’t all that far out though and that more and more scientists are coming to agree with the strange ideas he presents in this book. He says that he is not the only one thinking these strange ideas.  He has a lot of company here from some very reputable scientists.

Dennett seems to realize that most people are going to be very uneasy about the ideas in this book and he spends a lot of time trying to get his readers to not instantly reject what he is about to say.  

Dennett  begins the book by giving us a bird’s-eye view of the journey he will take. Life, he says has been evolving on Earth for 4 billion years. At first there was only bacteria and archaea, what are called the prokaryotes. Then one prokaryote and engulfed another one and found itself more fit and this new species took off with a roar.  

This kind of thing is really rare he says. Beneficial mutation is always exceedingly rare. And new speciation is exceedingly rare. (Speciation is  when some members of a species get isolated in genetic space from their parent population and form a new gene pool.)

The new species we are considering her came about thru the fortuitous collision of a bacterium and archaeon, and this new combination was fitter and it survived. This kind of combination of two previous species into one new species is called endosymbiosis. One partner ended up literally inside the other. This event was the birth of the eukaryotic cell which rapidly became more versatile than its ancestors which were two prokaryotic cells.  (The Eu in Eukaryotic means good.)  The first Eukaryotes led to multicellular life. Every living thing big enough to be visible is a multicellular eukaryote.

This combination of a bacterium and an archaeon was called was the Eukaryotic Revolution.  The Eukaryotic Revolution led to the next big transition which was the Cambrian Explosion. (The Cambrian explosion happened during several million years, 530 million years ago.)   Then came what Dennett calls the McCready explosion, which most people call the agricultural explosion. This explosion happened only 10,000 years ago, and for such a recent event it was a very big deal.  

Before the agricultural explosion ten thousand years ago, humans and all their life-stock were only .1% of all  the terrestrial, vertebrate biomass. Nowadays, humans plus their livestock are 98% of the terrestrial biomass. This, of course leaves out all invertebrates and all marine animals.

MacCready says the order in which humans developed is from high populations to high technology to high intelligence, not visa versa. Intelligence did not come first.  Instead, our intelligence depends on both our technology and our numbers.

[This is in agreement with a lot of other books I have been reading recently.  For example, The Secret of our Success: How Culture is Driving Human Evolution, Domestication Our Species and Making us Smarter by Joseph Henrich or The Knowledge Illusion: Why We Never Think Alone. ]

Dennett says that many of the mysteries of human consciousness disappear when we ask questions like “How minds could have arisen.” To say mind is an unspeakable mystery or spiritual or just not understandable is just a nonsensical cop-out.

Dennett says human minds are very different from the minds of all other species and many times were more powerful and versatile. He asks, isn’t this just the old fallacy of human exceptionalism?  Dennett says the idea of human exceptionalism actually provokes equal outrage in opposite directions. Some people are outraged that we should think we are so much superior than animals and others are outraged that we don’t accept that of course humans are infinitely superior to animals because of our rationality and our creation by God.

The argument over animal intelligence is a long running argument. The Romantics think all animals are hugely intelligent and the Killjoys think animals are mindless robots. Actually, both sides are right about some things and are wrong about other things says Dennett. We are not the god-like geniuses we sometimes think we are, and neither are the animals, but both can sometimes deal brilliantly  with the challenges of the real world.

To understand minds, Dennett says we have to loop around a lot, looking at a lot of different evidence and a lot of different history. And, Dennett says, we are necessarily  going to  have to start somewhere in the middle of things.  And that somewhere he chooses to start is going to be Descartes.

Descartes was one of the greatest scientists of the 17th century.  He formulated some of  the basic ideas of human minds, what they are and how they worked at the birth of modern science.

Descartes was wrong about a lot of things, but he actually was one of the great scientists of the 17th century.  He proposed the original TOE. This means the Theory of Everything. Descartes’ book on The Theory of Everything was called La Monde, The World.  

It took Newton to come up with a better physics in his Principia, which was an explicit refutation of the Descartes Theory. Descartes  thought all human minds were wonderful, not just his own. So he concluded that minds were not material but special stuff that didn’t have to obey the laws of physics. This was the beginning of what is now called  Cartesian dualism. This idea that minds are not matter wasn’t really invented by Descartes. The church had long ago said this.

[It seems to me that Plato was the first to articulate this idea clearly. Then the church turned Plato’s Forms into heaven and the Good into God.   

And the mind-body concept has been an unsolvable problem in Western thought and science for the last 2000 years. There is still there is still a lot of confusion that exist today about this idea. And it is not easily dispelled.  

This is really what Riccardo Manzotti in his recent articles and dialogue about consciousness in the New York Review of Books is really talking about when he says consciousness is something that does not square with contemporary science, and that there is an error with our conception of reality somewhere.  ]

Dennett says that it was Descartes who distilled Plato’s ideas about body-mind dualism into an actual theory. The problem with the mind-body conflict is that no one has ever been able to figure out how mind and body could actually interact without violating the laws of physics. The solution to the mind-body problem seems to be either a radical revolution in science or a declaration that things are just a mystery.

The mysterious linkage between mind and matter has been a battleground of scientists and philosophers since the seventeenth Century.   Just before he died, Francis Crick wrote a book called  The Astonishing Hypothesis: The Scientific Search for the Soul.

In this book  Crick says dualism is false. The mind just is the brain, he says. Actually he is saying nothing really new here. He goes on to discuss the fact that denying dualism also denies free will. Again he saying nothing really new here.   The idea that the mind is nothing but atoms and molecules and neurons following natural laws and that therefore there is no such thing as free well is a well discussed idea says Dennett.

Terrence Deacon, says Dennett, has thought about the mind-body problem more creatively and called it the “Cartesian Wound which severed mind from body at the birth of modern science.”   He is more intelligent than Crick about the mind-Body problem and Dennett says we should read this book.

But actually, no one has ever managed to really be very convincing about understanding the  mind-body problem.

Dennis says that he has devoted his entire career to trying explaining the mind body problem and he has never succeeded, but he says this time he is going to try and explain the whole story as best he can and that he can now do a better job than ever before. Why he asks? Because science has made tremendous progress in the last 20 years and that now, for the first time, we can take seriously a materialist  theory of the mind.

The next section is titled “Cartesian Gravity.” By this Dennett means that there are powerful forces distracting us from understanding mind, and these forces, when we try to think about the mind-body problem, lead us astray.  Feelings of meaninglessness, feelings that free will doesn’t exist are very uncomfortable.  It is much more comforting to call the whole subject of mind-body unsolvable, mysterious, magical and just shove the whole thing under the rug.  

Cartesian gravity is a disruptive force that screws up how we think says Dennett.  Cartesian gravity is also something that has evolved. We need to ask why it arose on earth to understand it. It will us take several passes over the same subject, covering different ground each time, to understand this. We tend to underestimate the forces that destroyed our thinking and  imagination, especially when confronted by instinctive convictions that seem undeniable. We don’t even try to deny these convictions, we just accept them blindly and automatically.

Dennett shows us a couple  of images to make his point.  He shows us an image that changes back and forth from a Duck to a Rabbit and the Necker Cube which also flips back and forth.  These are examples of how easily we can be deceived, how we are programmed to see certain things as true and obvious when they are really not the way they appear at all.


Chapter 2. Before bacteria and Bach.

Dennett  says we should try not to react intuitively against what he is going to be staying in this book. We have long been programmed to see certain things as true and obvious and they really are not way at all. He says that throughout this book we will need to accept uncomfortable facts without prematurely rebutting them. Dennett  says to cut him some slack.

The idea that great societies are great because of a few great Geniuses is wrong.   Human culture itself is a more secure source of brilliant innovation than any one single group of geniuses.

Dennett says it’s not individuals, but cultural evolution that is the real author of our finest achievements. He says culture evolves by means of Memes.   By saying this Dennett is merely trying to point out that there are strong forces out there pushing people’s thinking one way or another.  At this point, he is not saying that one point of view or another is necessarily right or wrong.  He also says we will return to the idea of memes later and look both pros and cons for the idea.

Dennett says that the simplest, earliest life form, something like a bacterium was already a complex and brilliantly designed self-maintaining system.  Then he asks, didn’t I just give aid to the Intelligent Design crowd? No, he answers.  He asks how a good materialist, atheist, Darwinian like himself could say such a thing?  Just hold on he says.

Dennett goes on to say that some Intelligent Design proponents often ask how could life even start without a miracle, without an intelligent designer.  They want to know how there could be evolution without first having life forms capable of reproducing.  If there is no designer, this would mean the accidental throwing together of molecules and hoping they would form DNA or RNA.  They say that creating life in this way would involve such a huge coincidence that could never happen.  Therefore, the first life forms would have to be designed by some kind of a Designer.  

Dennett says this is a defective argument; a combination of misdirection and failure of imagination, as he will later show.  But, he says, the intelligent design people are right in saying that the first concoction of molecules capable of reproducing itself must have been incredibly complex.  How could could have this happened without a designer?  This poses a real problem for us Darwinians. How could this have happened without some kind of miracle?

The way for us to proceed is clear says Dennett. One way of understanding how life could come about without a miracle would be to start with the most simple form of life and then reverse-engineer it.  You begin with the minimum specification for a living reproducible thing, everything  it has to be able to do, and then make an list of the available raw materials and then ask what non-miraculous sequence of events would bring them together to accomplish the job.  

If you can figure out one way in which this might be done, the Darwinians will have won.   Its kind like achieving checkmate in chess, Dennett says.  This will obviously be a tough job though.  And there are a lot of researchers working on it.  And, there have been some big breakthroughs in this project.  For instance the Powner, Gerland and Sutherland project in 2009.  They haven’t completely solved the problem, but have come up with a “remarkably efficient solution to the problem of prebiotic ribonucleotide synthesis.

Dennett says that throughout this book he will exploit this idea of reverse engineering. This is based on the premise that every living thing is a product of a non-mysterious, physical process that gradually brought all the elements together.  This is the way science always works.  The reverse-engineering perspective is ubiquitous in biology and is obligatory in  investigations of the origin of life.

One way reverse engineers work is to assume that all parts of an organism are good for something and then figuring out how they came about.  There are exceptions to this, but this assumption is usually very helpful.  However, this technique has been criticized by some (Gould and Lewotin)  as being adaptationism which is usually considered a big no-no by evolutionists.  Gould and Lewontin compared those who assume that everything in an organism is good for something to Voltaire’s Dr Pangloss who is of course a total idiot. Dennett says this is an unfair caricature of the use of optimality assumptions in biology and that is has had unfortunate effects.  The attack by some evolution-haters  as tantamount to a refutation of the theory of natural selection and this has convinced many biologists to discontinue the idea of reverse engineering.

However, those scientists working on the origin of life have generally ignored the Pangloss critique of their methods.  There are risks to this strategy but the rewards have also been great.  Sometimes using the shortcut of assuming the optimality  of all parts of an organism leads to mistakes and steps backward, but in the long run there is really no other way to proceed.  Dennett again uses the chess analogy:  chess gambits are strategies that give up material in order to achieve an improved position.  The same is true in scientific research.  Researchers cannot afford to ignore devious but fruitful trails just as the chess player cannot afford to overlook apparent mistakes by his opponent.  As Francis Crick famously said, “evolution is smarter than you are.”  The blind, purposeless churn of evolution is always uncovering off-the-wall solutions to problems but this is not evidence for an Intelligent Designer or for abandoning reverse engineering.  As Dennett says, “As in chess, don’t give up: learn from your mistakes and keep on exploring, a imaginatively as you can, bearing in mind that your hypotheses, however plausible, still risk disconfirmation, which should be conscientiously sought.”

Dennett gives an example of a possible gambit in the origin of life.



This article is still in progress.  It will be finished soon.

The Oxbow and Mount Moran, Dawn, Teton National Park, Wyoming.  Picture by Hanselmann Photography. 

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