BookTalk.org

Please use this thread to discuss the above listed chapter of "Darwin's Dangerous Idea: Evolution and the Meanings of Life" by Daniel Dennett.

I have a couple of questions I would like to throw out for discussion on this chapter.

First, Dennett says

time and again, they have come up with truly interesting challenges - leaps and gaps and other marvels that do seem, at first, to need skyhooks. But then along have come the cranes, discovered in many cases by the very skeptics who were hoping to find a skyhook.

So, for philosophers it is no doubt useful to determine whether, in general, skyhook ("mind first") approaches fail while crane (loosely, subprocesses of an algorithmic design process which are themselves algorithmic) approaches prove sufficient and therefore preferable. But imagined skyhook processes, by Dennett's own account, generate interesting cases.

Are we looking at a variation on the holism/reductionism theme? Do skyhook notions allow a holistic view which thereby puts on display whatever anomalies there may be which need their own subprocesses to address?

In my academic career I observed a difference between those who "believed in" deductive approaches, who tended to be aggressive police for analytical rigor, and those who "believed in" inductive approaches, who generated all the interesting observations but generally remained silent on methodology because their comparative advantage relied on processes held in disrepute. Is there a bias in the academic world against questions which do not fit neatly in the paradigm already in use?

Second, I think I have a quibble about his presentation on sex, which may illustrate the point I was just gnawing on. Dennett says that sex is useful in the long run, but "too expensive" in the short run, thus requiring a careful examination to justify (this examination is promised for later in the book). But "too expensive" turns out to mean "fails to pass on 50% of the genes of an organism." In fact, that is not an account of "expense" in Darwinian terms. The shortcut of assuming that genes operate with a "goal" of "passing themselves on" is not a careful or rigorous account at all of the selection process.

Expense, in Darwinian terms, must mean a burden on the ability of the organism to reproduce. So a more complete account says something like, "asexual reproduction permits a dramatic advantage to the better adapted individuals, so that they can, over the course of many generations, numerically dominate those who are less well adapted." The shortcut of assuming genes guide the process for the sake of their "goal" is not an actual mechanism.

And, just to flag a future point, there is an analogy to be drawn between the advantage of asexual reproduction and the advantage of polygamous sexual arrangements. In the latter, the most fit males reproduce much more than the less fit males. So there is an interesting question why monogamy ever caught on.

Separate issue. I like the account of the Baldwin Effect. It is useful to consider the way "plasticity" of adaptedness comes to carry an advantage.

It might sound obvious that flexibility of adaptedness is better than inflexibility, but as I think about it, the opposite seems true. Ecological niches may not be terrifically stable, but they do manage to persist over long periods of time. So, with the obvious exception of some ability to react to local variations, such as the ability of animals to move around over the landscape (or seascape), it looks like most kinds of flexibility are likely to be "too expensive" in terms of providing adaptation to rare and thus mainly irrelevant threats.

Probably an organism has to be somewhat omnivorous, and possibly carnivorous, to make general flexibility of adaptedness into an advantage rather than a costly extravagance. Thus it may have co-evolved with emergence of fruit-bearing trees, or some such "general" innovation in the environment which provides a variety of high quality food sources, and thus some benefit to plasticity.

Harry Marks wrote:Separate issue. I like the account of the Baldwin Effect. It is useful to consider the way "plasticity" of adaptedness comes to carry an advantage.

It might sound obvious that flexibility of adaptedness is better than inflexibility, but as I think about it, the opposite seems true. Ecological niches may not be terrifically stable, but they do manage to persist over long periods of time. So, with the obvious exception of some ability to react to local variations, such as the ability of animals to move around over the landscape (or seascape), it looks like most kinds of flexibility are likely to be "too expensive" in terms of providing adaptation to rare and thus mainly irrelevant threats.

Probably an organism has to be somewhat omnivorous, and possibly carnivorous, to make general flexibility of adaptedness into an advantage rather than a costly extravagance. Thus it may have co-evolved with emergence of fruit-bearing trees, or some such "general" innovation in the environment which provides a variety of high quality food sources, and thus some benefit to plasticity.

Glad you mentioned the Baldwin effect. Would you be able to summarize the point Dennett is making there? I'm just not sure I'm picking up the significance.

Harry Marks wrote: Second, I think I have a quibble about his presentation on sex, which may illustrate the point I was just gnawing on. Dennett says that sex is useful in the long run, but "too expensive" in the short run, thus requiring a careful examination to justify (this examination is promised for later in the book). But "too expensive" turns out to mean "fails to pass on 50% of the genes of an organism." In fact, that is not an account of "expense" in Darwinian terms. The shortcut of assuming that genes operate with a "goal" of "passing themselves on" is not a careful or rigorous account at all of the selection process.

I think you're taking "goal" too literally. I think a gene "trying" to be reproduced just means that a process that allows it to be passed on will tend to be selected for. So a process that leads to only a 50% pass rate will be costly in that sense, and the cost could also be in resources spent that could be used otherwise. There would need to be a major advantage to offset these costs.

DWill wrote:

Harry Marks wrote:I like the account of the Baldwin Effect. It is useful to consider the way "plasticity" of adaptedness comes to carry an advantage.

It might sound obvious that flexibility of adaptedness is better than inflexibility, but as I think about it, the opposite seems true. Ecological niches may not be terrifically stable, but they do manage to persist over long periods of time. So, with the obvious exception of some ability to react to local variations, such as the ability of animals to move around over the landscape (or seascape), it looks like most kinds of flexibility are likely to be "too expensive" in terms of providing adaptation to rare and thus mainly irrelevant threats.

Glad you mentioned the Baldwin effect. Would you be able to summarize the point Dennett is making there? I'm just not sure I'm picking up the significance.

Dennett has several balls in the air on this one, so it is possible that I am (or even he is) distorting the main issue. But let me take a stab. He wants to demonstrate how people motivated by the perception of a skyhook process (let's say, since he doesn't, that this is a belief that mind will "generate mind" in the evolutionary process by rewarding the flexibility to recognize a variety of opportunities in the ecological niche) might end up, indeed have ended up, discovering crane processes (special subprocesses of natural selection which can account for results challenging to the most simplistic version of the theory).

So Baldwin looked at the comparative rarity of truly advantageous opportunities ("Good Tricks") in "fitness space". Evidently a fourth surface on molars is one of those Good Tricks, but it won't work here. I might propose beavers building dams as a "Good Trick". (Dennett could use examples of his conceptual examples - evidently for a philosopher a "case" of academic work is a good example, but concepts are not the easiest blocks to build with for most of us.)

Baldwin noted that an exact adaptation (let's say, an instinct for building dams on streams) is a fairly difficult adaptation to hit spot on with genetic variation, but if the genotype includes adaptability in response to environment then any adaptation that is close (let's say, flat tails for swimming in streams) makes it more likely that the Good Trick will be discovered and built into the behavioral repertoire.

The bottom line point appears to be that the capability of response to environment has a "crane" for getting it past the expense of generating such flexibility, in that one need not start out so close to the Good Trick in adaptation space in order to get the ultimate benefit of it.

I have filled in some connections he left out, but I think I have fairly portrayed the point and that it is an interesting one.

Dexter wrote: I think you're taking "goal" too literally. I think a gene "trying" to be reproduced just means that a process that allows it to be passed on will tend to be selected for. So a process that leads to only a 50% pass rate will be costly in that sense, and the cost could also be in resources spent that could be used otherwise. There would need to be a major advantage to offset these costs.

I expect you are right about me taking it too literally, but the point of the book is "telos" and how teleological thinking is supposed to work. So I am trying to be very careful around any talk of "goals". In your rewrite of the point, for example, it needs to be said that the 50% pass rate only matters for advantageous genes, so, for example, all the neutral mutations used for the genetic clock are neutral on whether the pass rate should be high or low.

An interesting interview in the Financial Times. Dennett's take on some interesting topics, like AI, gets a quick once-over.

https://www.ft.com/content/96187a7a-fce ... 00c5664d30

Harry Marks wrote:. . . Second, I think I have a quibble about his presentation on sex, which may illustrate the point I was just gnawing on. Dennett says that sex is useful in the long run, but "too expensive" in the short run, thus requiring a careful examination to justify (this examination is promised for later in the book). But "too expensive" turns out to mean "fails to pass on 50% of the genes of an organism." In fact, that is not an account of "expense" in Darwinian terms. The shortcut of assuming that genes operate with a "goal" of "passing themselves on" is not a careful or rigorous account at all of the selection process.

Expense, in Darwinian terms, must mean a burden on the ability of the organism to reproduce. So a more complete account says something like, "asexual reproduction permits a dramatic advantage to the better adapted individuals, so that they can, over the course of many generations, numerically dominate those who are less well adapted." The shortcut of assuming genes guide the process for the sake of their "goal" is not an actual mechanism.

And, just to flag a future point, there is an analogy to be drawn between the advantage of asexual reproduction and the advantage of polygamous sexual arrangements. In the latter, the most fit males reproduce much more than the less fit males. So there is an interesting question why monogamy ever caught on.

Good points, Harry. For humans specifically, sex is the constant carrot dangling on the proverbial stick. So it drives us, sometimes makes us do crazy, stupid things. And, yet, it must not be too expensive in Darwinian terms, otherwise we wouldn't be here.

In the prologue, Dennett says: "Evolutionary thinking is all very well if you’re explaining the efficient wing of the albatross or the elegant nest of the weaverbird, but keep your dirty Darwinian hands off my “Ode to a Nightingale.”

He elaborates on this idea in Chapter 3:

Much of the controversy and anxiety that has enveloped Darwin’s idea ever since can be understood as a series of failed campaigns in the struggle to contain Darwin’s idea within some acceptably “safe” and merely partial revolution. Cede some or all of modern biology to Darwin, perhaps, but hold the line there! Keep Darwinian thinking out of cosmology, out of psychology, out of human culture, out of ethics, politics, and religion! In these campaigns, many battles have been won by the forces of containment: flawed applications of Darwin’s idea have been exposed and discredited, beaten back by the champions of the pre-Darwinian tradition. But new waves of Darwinian thinking keep coming. They seem to be improved versions, not vulnerable to the refutations that defeated their predecessors, but are they sound extensions of the unquestionably sound Darwinian core idea, or might they, too, be perversions of it, and even more virulent, more dangerous, than the abuses of Darwin already refuted?

Dennett mentions Stephen Jay Gould's concept of "nonoverlapping magisteria" but I was thinking of more recent begrudging acceptance of micro-evolution in creationist circles. They have redrawn the line there and it must have happened in recent years. But speciation or macroevolution continues to be denied at all costs. Keep Darwin's dirty ape hands off of that!

I like Dennett's sense of placing the modern synthesis of evolutionary theory in the context of pre-Darwinian thinking. In studying Shakespeare, I always like to refer to the great chain of being, which demonstrates a strict, religious hierarchical structure of all matter and life that was predominant from the Greeks to the Elizabethan era. Darwin literally changed everything. And it's always a struggle for us in modern times to truly grasp of how it was before.