From Bacteria to Bach and Back: The Evolution of Minds

by Daniel C. Dennett

evolution is a process that depends on amplifying things that almost never happen.

(the “eu” in “eukaryotic” is like the “eu” in euphonious, eulogy, and eugenics—it means good). Eukaryotes were the key ingredient to make possible multicellular life forms of all varieties.

the MacCready Explosion occurred in only about 10,000 years, or 500 human generations. According to MacCready’s calculations (1999), at the dawn of human agriculture 10,000 years ago, the worldwide human population plus their livestock and pets was only ~0.1% of the terrestrial vertebrate biomass. (We’re leaving out insects, other invertebrates, and all marine animals.) Today, by his estimation, it is 98%! (Most of that is cattle.)

Anthropocene explosion

our human intelligence created the technology (including agriculture) that then permitted the population boom, but as we shall see, evolution is typically an interwoven fabric of coevolutionary loops and twists:

native intelligence depends on both our technology and our numbers.

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.

I Am a Strange Loop (2007), describes a mind composing itself in cycles of processing that loop around, twisting and feeding on themselves, creating exuberant reactions to reflections to reminders to reevaluations that generate novel structures: ideas, fantasies, theories, and, yes, thinking tools to create still more.

(Yes, we have a soul, but it’s made of lots of tiny robots!)

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.

the prospect of denying dualism threatened horrible consequences as well: 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?

Terrence Deacon, has called “the Cartesian wound that severed mind from body at the birth of modern science”

There seem to be two competing orientations, the first-person point of view of the Defenders and the third-person point of view of the scientists,

The idea of Cartesian gravity, as so far presented, is just a metaphor, but the phenomenon I am calling by this metaphorical name is perfectly real, a disruptive force that bedevils (and sometimes aids) our imaginations,

When I hear the word “culture” I reach for my gun.6

the simplest reproducing thing is much too complex to arise by mere chance.

“Panglossian paradigm” as a deliberately abusive term for the brand of biology—adaptationism—that relies on the methodological principle of assuming, until proven otherwise, that all the parts of an organism are good for something.

Dr. Pangloss’s overfertile imagination, there was no quirk, no deformity, no catastrophe of Nature that couldn’t be seen, in retrospect, to have a function, to be a blessing, just what a benevolent God would arrange for us, the lucky inhabitants of the perfect world.

In chess, a gambit is a strategy that gives up material—a step backward, it seems—in order to take a better, forward step from an improved position.

Orgel’s Second Rule: “Evolution is cleverer than you are.”

Any system of thought that denies or seeks to explain away the overwhelming evidence for design in biology is ideology, not science.

Do we want to try to convince lay people that they don’t really see the design that is stunningly obvious at every scale in biology, or would we rather try to persuade them that what Darwin has shown is that there can be design—real design, as real as it gets—without an Intelligent Designer?

the physical stance, the design stance, and the intentional stance

physical stance is the least risky but also the most difficult; you treat the phenomenon in question as a physical phenomenon, obeying the laws of physics,

The design stance works only for things that are designed, either artifacts or living things or their parts, ...

The intentional stance works primarily for things that are designed to use information to accomplish their functions. It works by treating the thing as a rational agent, attributing “beliefs” and “desires” and “rationalit...

Evolution by natural selection is not itself a designed thing, an agent with purposes,...

it is a set of processes that “find” and “track” reasons for things to be arranged on...

The Blind Watchmaker (1986), nicely evokes the apparently paradoxical nature of these processes: on the one hand they are blind, mindless, without goals, and on the other hand they produce designed entities galore,

Evolutionary processes brought purposes and reasons into existence

How could mere large conglomerations of uncolored, unalive things add up to colored, live things? This is a rhetorical question that should be, and can be, answered (eventually).

meanings of “why.” The English word is equivocal, and the main ambiguity is marked by a familiar pair of substitute phrases: what for? and how come?” “Why are you handing me your camera?” asks what are you doing this for? “Why does ice float?” asks how come: what it is about the way ice forms that makes it lower density than liquid water?

The how come question asks for a process narrative that explains the phenomenon without saying it is for anything.

I was demanding a reason—a what for—and getting a process narrative—a how come—in reply.

The evolution of “why”: from how come to what for

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. How does this cascade of generative processes get under way?

In the abiotic world, many similar cycles occur concurrently but asynchronously, wheels within wheels within wheels, with different periods of repetition, “exploring” the space of chemical possibility.

In the world of software, two well-recognized phenomena are serendipity and its opposite clobbering. The former is the chance collision of two unrelated processes with a happy result, and clobbering is such a collision with a destructive result.

something alive but unevolvable. My term for such a phenomenon is a skyhook, named after the mythical convenience you can hang in the sky to hold up your pulley or whatever you want to lift (Dennett 1995). A skyhook floats high in Design Space, unsupported by ancestors, the direct result of a special act of intelligent creation.

Many people can’t abide Darwin’s strange inversion. We call them creationists. They are still looking for skyhooks—“irreducibly complex” (Behe 1996) features of the biosphere that could not have evolved by Darwinian processes.

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

What Darwin and Turing did was envisage the most extreme version of this point: all the brilliance and comprehension in the world arises ultimately out of uncomprehending competences compounded over time into ever more competent—and hence comprehending—systems.

Turing himself is one of the twigs on the Tree of Life, and his artifacts, concrete and abstract, are indirectly products of the blind Darwinian processes in the same way spider webs and beaver dams are, so there is no radical discontinuity, no need for a skyhook, to get us from spiders and beaver dams to Turing and Turing machines.

“Ontology” comes from the Greek word for thing. In philosophy, it refers to the set of “things” a person believes to exist, or the set of things defined by, or assumed by, some theory.

This common ontology was usefully named the manifest image by Wilfrid Sellars (1962).

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.

Jakob von Uexküll’s (1934) concept of the organism’s Umwelt, the behavioral environment that consists of all the things that matter

J. J. Gibson’s (1979) concept of affordances: “What the environment offers the animal for good or ill.”

design revision in Nature must follow the profligate method of releasing and test-driving many variants and letting the losers die, unexamined.

brilliantly designed motor proteins, proofreading enzymes, antibodies, and the cells they animate.