From Bacteria to Bach and Back: The Evolution of Minds

by Daniel C. Dennett

Life has been evolving on this planet for close to four billion years. The first two billion years (roughly) were spent optimizing the basic machinery for self-maintenance, energy acquisition and reproduction, and the only living things were relatively simple single-celled entities—bacteria, or their cousins, archaea: the prokaryotes.

evolution is a process that depends on amplifying things that almost never happen. For instance, mutation in DNA almost never occurs—not once in a billion copyings—but evolution depends on it.

Over billions of years, on a unique sphere, chance has painted a thin covering of life—complex, improbable, wonderful and fragile. Suddenly we humans … have grown in population, technology, and intelligence to a position of terrible power: we now wield the paintbrush. (1999, p. 19)

Some people would like to persuade the curious to keep their hands off the beloved mysteries, not realizing that a mystery solved is even more ravishing than the ignorant fantasies it replaces.

There are some people who have looked hard at scientific explanations and disagree: to their taste, ancient myths of fiery chariots, warring gods, worlds hatching from serpent eggs, evil spells, and enchanted gardens are more delightful and worthy of attention than any rigorous, predictive scientific story. You can’t please everybody.

The task is made difficult by a feature it doesn’t share with other scientific investigations of processes (in cosmology, geology, biology, and history, for instance): people care so deeply what the answers are that they have a very hard time making themselves actually consider the candidate answers objectively.

The problem with dualism, ever since Descartes, is that nobody has ever been able to offer a convincing account of how these postulated interactive transactions between mind and body could occur without violating the laws of physics.

If “we are just machines,” what happens to free will and responsibility? How could our lives have meaning at all if we are just huge collections of proteins and other molecules churning away according to the laws of chemistry and physics? If moral precepts were nothing but extrusions generated by the hordes of microbiological nano-machines between our ears, how could they make a difference worth honoring?

Evolutionary processes brought purposes and reasons into existence the same way they brought color vision (and hence colors) into existence: gradually.

good deed might be clumsily executed and even fail in its purpose, while a good tool might be an efficient torture device or evil weapon.

In Darwin’s Dangerous Idea (1995), I argued that natural selection is an algorithmic process, a collection of sorting algorithms that are themselves composed of generate-and-test algorithms that exploit randomness (pseudo-randomness, chaos) in the generation phase, and some sort of mindless quality-control testing phase, with the winners advancing in the tournament by having more offspring.

Before we can have competent reproducers, we have to have competent persisters, structures with enough stability to hang around long enough to pick up revisions.

Both Darwin and Turing claim to have discovered something truly unsettling to a human mind—competence without comprehension.

(In 1999, NASA’s $125-million Mars Climate Orbiter got too close to Mars because one part of the control system was using meters and another part was using feet to represent the distance from the planet. The spacecraft got too close and destroyed itself. People make mistakes.)

Comprehension, far from being a Godlike talent from which all design must flow, is an emergent effect of systems of uncomprehending competence: natural selection on the one hand, and mindless computation on the other.

Evolution, in contrast, has no goals, no predefined problems, and no comprehension to bring to the task; it myopically and undirectedly muddles along with what it has already created, mindlessly trying out tweaks and variations, and keeping those that prove useful, or at least not significantly harmful.

a process with no Intelligent Designer can create intelligent designers who can then design things that permit us to understand how a process with no Intelligent Designer can create intelligent designers who can then design things.

The behavior is neither a simple “knee-jerk” reflex inherited from her ancestors nor a wily scheme figured out in her rational mind; it is an evolution-designed routine with variables that respond to details in the circumstances, details that the sophisticated soliloquy captures—without excess—in the rationale of that design.

Linguists and philosophers of language use the term pragmatics to refer to those aspects of meaning that are not carried by the syntax and “lexical” meanings of the words but conveyed by circumstances of particular utterances, by the Umwelt, in effect, of an utterance.

The law of copyright tries to separate “utilitarian” function from aesthetic function, and while there are good legal reasons for trying to make this a bright-line distinction, there are good theoretical reasons for seeing this as an ad hoc undertaking, as Learned Hand observes about the “idea”/“expression” distinction.

If the brain were an organ for secreting bile or purifying the blood, the chemistry and physics of the working parts would matter greatly, and it might be impossible to find suitable substitutes for the materials used, but the brain is an information-processor, and information is medium-neutral. (A warning or a declaration of love or a promise can be “made out of anything,” provided the recipient has the know-how to pick it up.)

Brains are more like termite colonies than intelligently designed corporations or armies.

are very unlike the computers in use today. Composed of billions of idiosyncratic neurons that evolved to fend for themselves, the brain’s functional architecture is more like a free market than a “politburo” hierarchy where all tasks are assigned from on high.

The fundamental architecture of animal brains (including human brains) is probably composed of Bayesian networks that are highly competent expectation-generators that don’t have to comprehend what they are doing. Comprehension—our kind of comprehension—is only made possible by the arrival on the scene quite recently of a new kind of evolutionary replicator—culturally transmitted informational entities: memes.

The brain-tokens will not look like “word” or sound like “word” (they’re brain events, and it’s dark and quiet in there), but they will no doubt be physically similar to some of the events that normally occur in your brain when you see or hear “word.”

Language evolved to fit the brain before the brain evolved to better accommodate language.

Synanthropy is probably the route to domestication taken by most of our domesticated species. For instance, as Coppinger and Coppinger (2001) argue, the myth of wolves being turned into dogs via the deliberate removal of wild wolf pups from their dens by intrepid domesticators is hardly plausible. Almost certainly once human settlements began to generate concentrations of discarded edible food, these dumps became attractive to wild wolves who varied, initially, in their ability to tolerate proximity to dangerous human beings. Those who could bear to be that close became geographically and reproductively isolated from their more wary cousins, who kept their distance, and what emerged over time was the junkyard dog, belonging to nobody, nobody’s pet or companion, but a familiar presence in the community, like house mice, rats, and squirrels. Dogs in effect domesticated themselves over many generations until their human neighbors became their owners, their companions, their guardians, their masters.

the manifest image of each species: a user-illusion brilliantly designed by evolution to fit the needs of its users.

A better analogy for a gene than either a word or a sentence is a toolbox subroutine in a computer.

Darwinian evolutionary processes are amplifiers of noise.

Speaking without gesturing is a difficult feat for many people, and it might be that gesturing and vocalizing have traded places, with gestures now playing the embellishing role that was originally played by vocalizations. The vestigial hand movements so many of us find all but irresistible may in effect be fossil traces of the original languages.

Human culture started out profoundly Darwinian, with uncomprehending competences generating various valuable structures in roughly the way termites build their castles. Over the next few hundred thousand years, cultural exploration of Design Space gradually de-Darwinized, as it developed cranes that could be used to build further cranes that lifted still more cranes into operation, becoming a process composed of ever more comprehension.

They knew the reasons, and we are grateful that they taught us, even though they didn’t tell us why. It’s a short step from here to God works in mysterious ways.

the heroic age of intelligent design is beginning to wane just when its would-be heroines are finally getting to prove their powers.

Our ability to do this kind of thinking is not accomplished by any dedicated brain structure not found in other animals. There is no “explainer-nucleus” for instance. Our thinking is enabled by the installation of a virtual machine made of virtual machines made of virtual machines. The goal of delineating and explaining this stack of competences via bottom-up neuroscience alone (without the help of cognitive neuroscience) is as remote as the goal of delineating and explaining the collection of apps on your smartphone by a bottom-up deciphering of its hardware circuit design and the bit-strings in memory without taking a peek at the user interface.

And what is this self? Not a dedicated portion of neural circuitry but rather like the end-user of an operating system.

people tend to treat belief in the supernatural as not only excusable but also morally praiseworthy. Credulity is next to godliness.

If the brain were so simple we could understand it, we would be so simple we couldn’t.

I believe it was John Cage who once told me, “When you start working, everybody is in your studio—the past, your friends, enemies, the art world, and above all, your own ideas—all are there. But as you continue painting, they start leaving, one by one, and you are left completely alone. Then, if you’re lucky, even you leave.” (2011, p.