Discuss Daniel Dennett’s From Bacteria to Bach and Back: The Evolution of Minds

On August 16, 2025, six of us reviewed the three conditions needed for Darwinian evolution in Daniel Dennett’s From Bacteria to Bach and Back. These requirements form an algorithm that describes how organisms evolve. However, it cannot predict future events as well as the physics formula that precisely predicts where an arrow lands after it is launched from a bow, prompting some critics to claim Darwinian evolution is not scientific. Though the fossil record is incomplete, Darwinian evolution guides paleontologists to find transitional fossils in higher sedimentary layers. Although biology is considered a descriptive science, so is astronomy. As evidence from observations accumulated, astronomers shifted from the geocentric to the heliocentric interpretation. Mendelian genetics and DNA sequences provide further evidence that supports Darwin’s interpretation of evolution, thereby widening the credibility gap between it and other interpretations. Science is a process of making explanations that are consistent with observations without resorting to a deus ex machina.

How did brains evolve? Even the simplest organism, such as bacteria, can sense gradients so that it can move away from toxic environments and move toward nutrients that foster growth and reproduction. As multicellular organisms evolve, some cells become neurons, specializing in sensing changes in the environment and coordinating the organism’s responses to it. As animals become more complex, their brains evolve to handle the many tasks to keep their bodies functioning. Earth has evolved humans, and we have become the apex omnivore. When humans domesticated livestock 10,000 years ago, the total mass of humans and their livestock made up less than 0.1% of the biomass of terrestrial vertebrates. Now, Paul MacCready estimates humans and their livestock make up 98% of terrestrial vertebrate biomass. What was special about human brains that made the MacCready explosion possible?

Are brains computers? Owen Holland developed the SlugBot, which feeds on slugs in grain fields and digests them to generate electricity to power the microprocessors that control it. However, the SlugBot is not able to repair and maintain itself, nor even make offspring and evolve, a distinction still held by living things. Although brains and computers are physical devices that use signals, the brain coordinates signals with neurons made of carbon, utilizing carbon compounds such as neuromodulators as signals, and uses oxygen to metabolize glucose to power its activities, making the brain an analog and not a digital processor. Brains are made of multiple analog processors working in parallel, enabling us to coordinate information and actuate muscles to accomplish tasks such as walking along crowded sidewalks without bumping into other pedestrians or driving a car on the highway without crashing into other cars. The brain uses Bayesian statistical estimations rather than computing precise, exact values.

One task that computers find difficult to do is reading handwritten letters that a first grader can read at a glance. The student uses Bayesian processing of prior expectations to read scribbles on a page, but a digital computer needs to search deeply in its database to decipher them. When you are solving a math word problem, are you conscious of the parallel processing that eventually bubbles up to an approach that gets the answer? Brains are composed of billions of idiosyncratic neurons organized in modules running in parallel, bubbling up solutions for us to choose to solve problems. Those brain modules are examples of competence without comprehension. Comprehension arises from those competences. The brain is now equipped to host another kind of replicator, memes.

By the way, Dennett advocates an approach to education that develops competence without comprehension. In the movie The Karate Kid, Daniel LaRusso learns karate with Mr. Miyagi, who starts by having Daniel put wax on Mr. Miyagi’s old car and rubbing it off using a specific set of motions. After several days, Daniel was tired of waxing the car and confronted Mr. Miyagi, asking how doing this tedious task would help him learn karate. Mr. Miyaki throws several punches at Daniel, who has gained the strength and quickness from waxing the car, and deftly blocks Mr. Miyaki’s punches. We struggle through Daniel Dennett’s text, trying to make sense of it, but going through the motions of reading this book will give us the strength and quickness to counter-punch those who use science as a punching bag.

We invite you to find out how memes can infect and affect our comprehension in our continuing discussion of Daniel Dennett’s From Bacteria to Bach and Back: The Evolution of Minds, B105.C477D445 2017, on August 30, 2025, from 2 PM to 4 PM.