Darwin's Dangerous Idea by Daniel Dennett

Rating: 8/10

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High-Level Thoughts

A wonderful book about evolution and what it means for our interpretation of life. It’s tough to get through at parts, there’s a ~100pg section refuting his critics that you can mostly skip, but it’s brilliant and makes you rethink the meaning of life.

Summary Notes

Tell Me Why

In all his brilliant musings, Darwin never hit upon the central concept, without which the theory of evolution is hopeless: the concept of a gene. Darwin had no proper unit of heredity, and so his account the process of natural selection was plagued with entirely reasonable doubts about whether it would work.

A teleological explanation is one that explains the existence or occurrence of something by citing a goal of purpose that is served by the thing. Artifacts are the most obvious cases; the goal or purpose of an artifact is the function is was designed to serve by its creator.

If Locke is right, Mind must come first—or at least tied for first. It could not come into existence at some later date, as an effect of some confluence of more modest, mindless phenomena.

An Idea is Born

Natural selection would inevitably produce adaptation, as the summary makes clear, and under the right circumstances, he argued, accumulated adaptation would create speciation. Darwin knew full well that explaining variation is not explaining speciation. The animal-breeders he pumped so vigorously for their lore knew about how to breed variety within a single species, but had apparently never creates a new species, and scoffed at the idea that their particular different breeds might have a common ancestor.

Darwin had discovered the power of an algorithm. An algorithm is a certain sort of formal process that can be counted on—logically—to yield a certain sort of result whenever it is “run” or instantiated.

… the tactic of finessing ignorance by randomly generating a candidate and then testing it out technically is a ubiquitous feature of interesting algorithms. Not only does it not interfere with their provable powers as algorithms; it is often the key to their power.

… the most common misunderstanding of Darwinism: the idea that Darwin showed that evolution by natural selection is a procedure for producing Us. [56]

[Annealing: Evolution can be thought of like the way to forge a sword or other metalwork, constantly heating and let cool the metal and banging it into place, which better aligns its molecular structure over time.] [57]

Here, then, is Darwin’s dangerous idea: the algorithmic level is the level that best accounts for the speed of the antelope, the wing of the eagle, the shape of the orchid, the diversity of species, and all the other occasions for wonder in the world of nature. [59]

Universal Acid

What, then, are living things? they are things that defy this crumbling into dust (entropy), at least for a while, by not being isolated—by taking in from their environment the wherewithal to keep life and limb together. [69]

Consider how expensive would it be to make a device that would take scrambled eggs as input and deliver unscrambled eggs as output? There is one ready solution: put a live hen in the box! [70]

Was it not unfortunate, in fact, that Darwin had chosen to call his principle “natural selection,” with its anthropomorphic connotations? Wouldn’t it have been better, as Asa Gray suggested to him, the replace the imagery about “nature’s Guiding Hand” with a discussion of the different ways of winning life’s race? [73]

Let us understand that a skyhook is a mind-first force or power or process, an exception to the principle that all design, and apparent design, is ultimately the result of mindless motiveless mechanicity. A crane, in contrast, is a subprocess or special feature of a design process that can be demonstrated to permit the local speeding up of the basic, slow process of natural selection, and that can be demonstrated to be itself the predictable (or retrospectively explicable) product of the basic process. [76]

He cites the “Prelude…Ant Fugue,” about how our minds could be a bunch of ants running around, in GEB as a great example of reductionism “in its proper place.”

Greedy reductionists think that everything can be explained without cranes, good reductionists think that everything can be explained without skyhooks.

Darwin’s dangerous idea is that Design can emerge from mere Order via an algorithmic process that makes no use of pre-existing Mind. Skeptics have hoped to show that at least somewhere in this process, a helping hand )more accurately, a helping Mind) must have been provided—a skyhook to do some of the lifting. In their attempts to prove a role for skyhooks, they have often discovered cranes: products of earlier algorithmic processes that can amplify the power of the basic Darwinian algorithmic processes that can amplify the power of the basic Darwinian algorithm, making the process locally swifter and more efficient in a nonmiraculous way. Good reductionists suppose that all Design can be explained without skyhooks: greedy reductionists suppose it can all be explained without cranes.

The Tree of Life

Surely many more species have gone extinct than now exist—perhaps a hundred extinct species for every existent species. [86]

Speciation can now be seen to be a phenomenon in nature that has a curious property: you can’t tell that it is occurring at the time it occurs! You can only tell much later that it has occurred, retrospectively crowning an event when you discover that its sequels have a certain property. [96]

Other concepts exhibit similar curiosities. I once read about a comically bad historical novel in which a French doctor came home to supper one evening in 1802 and said to his wife “Guess what I did today! I assisted at the birth of Victor Hugo!” [96]

Mitochondrial Eve is the woman who is the most recent direct ancestor in the female line, of every human being alive today. She’s not necessarily the first human, just the oldest one that we’re all related to by chance. [97]

The major branching that we would retrospectively crown as the parting of the plants from the animals began as a segregation of two gene pools every bit as inscrutable and unremarkable at the time as any other temporary drifting apart of members of a single population. [100]

When what provokes our curiosity are the large patterns in phenomena, we need an explanation at the right level. In many instances this is obvious. If you want to know why traffic jams tend to happen at a certain hour every day, you will still be baffled after you have painstakingly reconstructed the steering, braking, and accelerating processes of the thousands of drivers whose various trajectories have summed to create those traffic jams. [102]

The Possible and the Actual

Does it make a real difference if the winning lottery number is chosen after you buy your ticket, or do you still have an opportunity to win, a real opportunity, if the winning number is sealed in a vault before the tickets are put on sale?

Even completely intact dinosaur DNA would be powerless to re-create a dinosaur without the aid of a dinosaur DNA reader, and those are just as extinct as dinosaurs. You need a dinosaur ovary. [114]

There aren’t any [horned birds], and we don’t know why. Might it be because they are ruled out by a biological law? Are horned birds flat impossible? [122]

Threads in Actuality in Design Space

In chess, when there’s only one way of staving off disaster, it is called a forced move. Such a move is not forced by the rules of chess, and certainly not by the laws of physics, but by what Hume might call a “dictate of reason.” [128]

If we found the inhabitants of another planet using our arabic numerals, we would be quite sure that it was no coincidence, that there had to be a historical connection. Why? Because the space of possible numeral shapes in which there is no reason for choosing one over the other is Vast; the likelihood of two independent “searches” ending up in the same place is Vanishing. [131]

There is only one design space, and everything actual in it is united with everything else. [135]

[We could lose the Principia, and math would still have been figured out. But if we lost the Eiffel Tower’s designer, it never would have been built.] [140]

Priming Darwin’s Pump

We’re seriously trying to get at the truth here, and if you think that this common but unspoken understanding about faith is anything better than socially useful obfuscation to avoid mutual embarrassment and loss of face, you have either seen much more deeply into this issue than any philosopher ever has… or you are kidding yourself. [154]

Here is a quandary: since living things have existed for only a finite time, there must have been a first one but since all living things are complex, there couldn’t have been a first one! [156]

… the building blocks of life began their careers as quasi-parasites of sorts, clinging to replicating clay particles and growing in complexity in the furtherance of the “needs” of the clay particles until they reached a point where they could fend for themselves. No skyhooks—just a ladder that could be thrown away… once it had been climbed. [158]

What must be the case is not that we are here, but that since we are here, we evolved from primates. [166]

Biology is Engineering

The Local Rule is fundamental to Darwinism; it is equivalent to the requirement that there cannot be any intelligent (or “far-seeing”) foresight in the design process, but only ultimately stupid opportunistic exploitation whatever lucky lifting happens your way. [191]

Only some things in the universe manifest intentionality. A book or a painting can be about a mountain, but a mountain itself is not about anything. A map or a sign or a dream or a song can be about Paris,but Paris is not about anything… Where does intentionality come from? It comes from minds, of course. [205]

… you are made of robots—or what comes to the same thing, a collection of trillions of macromolecular machines. And all of these are ultimately descended from the original macros. So something made of robots can exhibit genuine consciousness, or genuine intentionality, because you do if anything does. [206]

And if the winner of a [coin flipping] tournament thinks there has to be an explanation of why he won, he is mistaken: there is no reason at all why he won; here is only a very good reason why somebody won. [214]

Evolution does explain all the features that you inherited from your ancestors, but not by explaining why you are lucky enough to have them… Consider: you order a new cary, and specify that it be green. On the appointed day, you go to the dealership and there it sits, green and new. Which is the right question to ask: “Why is this car green?” or “Why is this green car here?” [215]

Achievements that at first seem either literally miraculous or at least intrinsically Mind-dependent can be broken down into the ever smaller achievements of ever smaller and stupider mechanisms. [228]

Searching for Quality

Even small children can readily learn to manipulate such complicated objects as VCRs… They are operating from what I call the design stance.

The VCR repairer knows a great deal more about the design of the VCR, and knows, roughly, how all the interior parts interact to produce both proper functioning and pathological functioning, bt may also be quite oblivious of the underlying physics of the processes. Only the designer or the VCR had to understand the physics; they are the ones who must descend to what I call the physical stance…

But when they engage in reverse engineering, of some other manufacturer’s VCR, they avail themselves not only of the physical stance, but also of what I call the intentional stance—they try to figure out what the designers had in mind. [229]

The aquatic apes theory! [243] Aquatic ape hypothesis

The tragedy of the commons occurs when there is a finite “public” or shared resource that individuals will be selfishly tempted to take more of than their fair share—such as the edible fish in the oceans. This is also why redwoods and other trees have to keep making themselves as tall as possible.

Bully for Brontosaurus

Intentional objects are the creatures of beliefs, and hence they play a more direct role in guiding (or misguiding) people’s behavior than do the real objects they purport to be identical to. The gold in Fort Knox, for example, is less important than what is believed about it, and the Albert Einstein myth is, like Santa Claus, much better known that the relatively dimly remembered historical fellow. [262]

The Cranes of Culture

But why does sleep need a “clear biological function” at all? It is being awake that needs an explanation, and presumably, its explanation is obvious. Animals—unlike plants—need to be awake at least part of the time, in order to search for food and procreate… Being awake is relatively costly, compared with lying dormant. [339]

[To Mother Nature] A life of sleep is as good a life as any other, and in many regards better—certainly cheaper—than most. [340]

A scholar is just a library’s way of making another library. [346]

The invasion of human brains by culture, in the form of memes, has created human minds, which alone among animal minds can conceive of things distant and future, and formulate alternative goals. The prospect for elaborating a rigorous science of memetic are doubtful, but the concept provides a valuable perspective from which to investigate the complex relationship between cultural and genetic heritage.

Losing Our Minds to Darwin

When comparing the time scales of genetic and cultural evolution, it is useful to bear in mind that we today—every one of us—can easily understand many ideas that were simply unthinkable by the geniuses in our grandparent’s generation! [377]

Science, however, is not just a matter of making mistakes, but of making mistakes in public. Making mistakes for all to see, in the hopes of getting the others to help with the corrections. [380]

The Evolution of Meanings

Then your selfish genes can be seen to be the original source of your intentionality—and hence of every meaning you can ever contemplate or conjure up—even though you can then transcend your genes, using your experience, and in particular the culture you imbibe, to build an almost entirely independent locus of meaning of the base your genes have provided. [426]

The Emperor’s New Mind, and Other Fables

… what Godel proved, beyond any doubt, is that when it comes to axiomatizing simple arithmetic, there are truths that “we can see” to be true but that can neverbe formally proved to be true.

To make the question more specific, consider some rather special varieties of mathematical truth. It is well known that there can be no all-purpose program that can examine any other program and tell whether or not it has an infinite loop in it, and hence will not stop if started. This is known as the Halting Problem, and there is a Godel-style proof that it is insoluble. [449]

On the Origin of Morality

The genetic fallacy—the mistake of inferring current fiction or meaning from ancestral function or meaning. [465]

Does that mean that religious texts are worthless as guides to ethics? Of course not. They are magnificent sources of insight into human nature, and into the possibilities of ethical codes. Just as we should not be surprised to discover that ancient folk medicine has a great deal to teach modern high-tech medicine, we should not be surprised if we find that these great religious texts hold versions of the very best ethical systems any human culture will ever devise. [476]

… in all the mammalian species that have so far been carefully studied, the rate at which their members engage in the killing of conspecifics is several thousand times greater than the highest homicide rate measured in any American city. [478]

What is the reasonable and just response of insurance companies to the actuarial facts about the different life expectancies of men and women? Is it fair to adjust their premiums accordingly? Or should we treat both genders alike in the premium department and accept their differential rate of receiving benefits as fair? [482]

… Jane Lancaster does in fact object to the word “harem” used to refer to the group of females guarded and mated by a single male—such as an elephant seal; she recommends the term “one-male group” since these females are “virtually self-sufficient, except for fertilization.” [492]

Redesigning Morality

For the most part, philosophers have been content to ignore the practical problems of real-time decision-making, regarding the brute fact that we are all finite and forgetful, and have to rush to judgment, as a real but irrelevant element of friction in the machine whose blueprint they are describing. [496]

We need to have “alert,” “wise” habits of thought—or, in other words, colleagues who will regularly, if not infallibly, draw our attention in directions we will not regret in hindsight. [505]

Faced with a world in which such predicaments are not unknown, we can recognize the appeal of a little old-time religion, some unquestioning dogmatism that will render agents impervious to the subtle invasions of hyper rationality. [508]

Ethical decision-making, examined from the perspective of Darwin’s dangerous idea, holds out scant hope of our ever discovering a formula or an algorithm for doing right. But that is not an occasion for despair; we have the mind-tools we need to design and redesign ourselves, ever searching for better solutions to the problems we create for ourselves and others. [510]

The Future of an Idea

The genius exhibited by Mother Nature can be disassembled into many acts of micro-genius—myopic or blind, purposeless but capable of the most minimal sort of recognition of a good (a better) thing. [511]

There is no “natural” way to mark the birth of a human “soul” any more than there is a “natural” way to mark the birth of a species. [513]

Those who think that we should preserve the elephants’ pristine environment at all costs should contemplate the costs of returning the United States to the pristine conditions in which the buffaloes roam and the deer and the antelope play. We must find an accommodation. [515]

If your religion advocates slavery, or mutilation of women, or infanticide, or puts a price on Salman Rushdie’s head because he has insulted it, then your religion has a feature that cannot be respect. It endangers us all. [516]

And there’s the rub. What will happen, one may well wonder, if religion is preserved in cultural zoos, in libraries, in concerts and demonstrations? It is happening: the tourists flock to watch the Native American tribal dances, and for the onlookers it is a folklore, a religious ceremony, certainly, to be treated with respect, but also an example of a meme complex on the verge of extinction… [520]

Is something sacred? Yes, say I with Nietzsche. I could not pray to it, but I can stand in affirmation of its magnificence. The world is sacred. [520]

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