Dennett’s book “From Bacteria to Bach and Back”

by Neil Rickert

This post will be mostly rambling notes, rather than a review.

The subtitle of the book is “The Evolution of Minds” and that perhaps better describes what Dennett is trying to do in this book.  I started reading this book almost a year ago.  And then I put it down to take a break.  I have recently resumed reading, starting again from the beginning.

I mostly disagree with Dennett.  Yet I see this as an important book, particularly for people with an interest in minds and consciousness.

Dennett is, himself, some sort of heretic.  He disagrees with conventional view of the mind.  But his disagreement is not enough for me, nor is it is a direction that fits my views.

Cartesian thinking

Dennett is critical of the dualism coming from Rene Descartes.  This is not particularly surprising.  Many philosophers and scientists have rejected dualism.  Descartes argued that the mind could not work in the mechanistic way that we see with human inventions (such as clocks, for example).  So he idea was that minds were constituted of an immaterial substance.

Dennett embraces Descartes ideas of mechanism, as what we can expect in the physical world.  But he rejects the idea that minds are different.  He (Dennett) takes the view that it is all mechanism.

I agree with Dennett to the extent of opposing dualism.  But I am not persuaded that “mechanical” is a useful descriptive term for biological organisms.

Natural selection

Dennett discusses natural selection at great length.  He sees it as a great explanation of how minds evolved.  Stephen J. Gould famously criticized Dennett about his use of Darwinism in an earlier book.  I lean toward Gould’s position in that debate.  One of my disagreements with Dennett, is that I see him overusing natural selection.

My problem here, is that Dennett wants to explain far too much with natural selection.  If NS explains everything, then it explains nothing.  Or, at least, it doesn’t explain anything very well.


Dawkins came out with the idea of memes (cultural memes), and how natural selection works with those.  Dennett takes that up, and uses it to explain the origin of language and  the origin of human reason.

Personally, I have never cared for the idea of memes.


Dennett attempts to explain where understanding comes from.  He illustrates this with the idea of an elevator operator, who would stop the elevator at the right position, and warn people to watch their step.  Today, there are very few elevator operators.  They have been replaced by automatic elevators, where the riders press buttons to indicate the floor where they want to stop.  Dennett describes the operation of the automatic elevator as “competence without comprehension”.

Dennett then uses this phrase “competence without comprehension” to illustrate the evolution of understanding.  His idea is that natural selection will select for competence.  And he presumes that comprehension and understanding will eventually emerge from that concentrated competence.  I’m not persuaded that this is the full story of how understanding can arise.


He discusses information at some length.  Unfortunately, “information” is used to mean many different things.  Dennett mentions Shannon information (defined in Shannon’s theory of communication).  But he spends more time on what he calls “semantic information”.  I see this as a huge mistake, not just by Dennett but by most people studying human cognition.  I’ll probably do a future blog post on information.

Consciousness as illusion

Dennett is often criticized for suggesting that consciousness is an illusion.  But perhaps they have not fully understood.  Then again, with Dennett’s talk of “competence without comprehension,” perhaps they have as much understanding as Dennett could expect.

It will help here to mention the terms “manifest image” and “scientific image”.  I believe they were introduced by Wilfrid Sellars.  To a first approximation, the manifest image is the world as we see it, and the scientific image is the world as it is seen by science.  For example, we see a dining table as solid and smooth.  Science sees it as mostly space between atoms.  Personally, I always took those “images” to be complementary.  But Dennett seems to take them to be inconsistent.  Here’s part of what he says about consciousness as an illusion:

The manifest image that has been cobbled together by genetic evolutionary processes over billions of years, and by cultural evolutionary processes over thousands of years, is an extremely sophisticated system of helpful metaphorical renderings of the underlying reality uncovered in the scientific image. It is a user-illusion that we are so adept at using that we take it to be unvarnished reality, when in fact it has many coats of intervening interpretive varnish on it.

So Dennett seems to see the scientific image as factual, and the manifest image as an illusion that evolution has created for us so as to make it easier for us to manage.


I’ve briefly discussed some of the highlights of Dennett’s book.  I mostly disagree, because I am more of a heretic than is Dennett.  However, if you are interested in questions related to human cognition, this is a book that is worth reading, even if you will end up disagreeing with Dennett.

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