Wednesday, May 02, 2007

Cato on Employment Verification

Jim Harper of the Cato Institute testified at the House's Hearing on Proposals to Improve the Electronic Employment Verification System last week, and made some very important points about privacy and government intrusiveness. Here are some quotes. There is much more valuable material in the complete text.

[I]mprovements that prevent eligible citizens from working should not be adopted. It is more important that American citizens and eligible people should be able to work than it is to exclude illegal aliens from working. There is probably no way to change the current system so that it prevents more ineligible people from working without also preventing more citizens and eligible people from working. [...]

The policy that will dissipate the need for electronic verification by fostering legality is aligning immigration law with the economic interests of the American people. [...]

Because the I-9 process and employer sanctions seek to defeat their economic interests, the system has two principle opponents: employers and workers. It relies on them for implementation, though, which is why success has been so elusive and will continue to be. [...]

Let there be no illusion that people seeking redress for a "tentative nonconfirmation" from the Social Security Administration or the Department of Homeland Security will enjoy a pleasant, speedy process. [...] People will wait in line for hours to access bureaucrats that are not terribly interested in getting them approved for employment. [...]

Electronic verification would have far greater privacy consequences than the current system — and these consequences would fall on American citizens, not on illegal immigrants. [...]

Ironically, all of this government spending and expanded bureaucracy would go toward preventing productive exchanges between employers and workers. Taxes and spending would rise to help stifle U.S. economic growth. Astounding.

Sunday, April 22, 2007

Cell Phones in the Third World

This year's Edge question: "What are you optimistic about?" generated more responses than earlier years' questions, so it has been taking me a while to get through the whole thing. The best line I've read so far (I'm on page 13 of 16) is by Sandy Pentland of MIT:
The International Telecommunications Union estimates that in the poorest countries each additional cell phone installed adds $3000 to the GDP, primarily due to the increased efficiency of business processes.

Sunday, April 01, 2007

Lee Smolin, The Trouble with Physics

Lee Smolin's book The Trouble with Physics is a very well written overview of the state of modern physics. I've been trying to keep up with String Theory, Quantum Theory, wormholes, and all the rest for quite some time, but until now I hadn't noticed that I was looking at trees and didn't know which forest any of them were in. Smolin's book gives a feeling for the lay of the land while he sets about laying waste to String Theory, which has been the great hope for a final unified theory for 25 years or so. I want to come back to the survey, but I'll cover what Smolin has to say about String Theory first, since that was his focus.

String Theory, it turns out, is a family of theories which matches what we know about the universe in some telling details, but which has too many loose ends to give specific predictions on any of the things we know we don't know. The basic idea gives an outline for what a more specific theory would look like, but there's nothing in the outline that gives a rigorous suggestion for how to fill in about thirty parameters that it leaves open. People in the field have been expecting that if someone does the right experiment or makes the right guess about one parameter, that the equations will fall into place, and the rest of the implications will be obvious. But it hasn't happened yet, and the brightest people in physics have been pursuing this path for a couple of decades.

One of Smolin's simplest demonstrations that the field has been unproductive recently is a description of the steady progress that has been made in fundamental physics for more than 200 years. From 1780 through 1980, there wasn't a quarter century that passed without important new contributions to our understanding of the basics of matter, time, energy, and motion. But most of what has been added since 1980 is String Theory, along with Dark Matter and Dark Energy. But Dark Matter and Dark Energy are questions, not answers and String Theory doesn't make any predictions that aren't made by the Standard Model, which was completed in 1973. String Theory also doesn't seem able to produce a theory that incorporates the background independence that general relativity requires.

Smolin is convinced that a major cause of the problem is that a form of groupthink has enveloped all of theoretical physics, enforced (probably unconsciously) by the oldest generation of theorists. He shows that the standard signs are all present, and shows how it has restricted researchers' choices of what to areas to explore. It's a plausible charge; I've seen compelling cases in at least two other fields that similar dynamics prevented progress for decades at a time.

Smolin ends with a plea that more research effort be funded in a variety of areas that are at odds with mainstream String Theory. He does a reasonable job of showing that they have some promise, though I'll admit that I'm way out of my depth by the time he gets here.

But I was really impressed by the first section of the book, in which Smolin presented all of fundamental physics from Copernicus, Bruno, and Galileo to the present day in a very approachable format. The focus was consistently on what pre-existing concepts were brought together in one of two ways. Sometimes the unification shows that two familiar things that are thought of as distinct are really the same thing, giving a deeper theory of both. (the Earth is one planet among several, the Sun is one star among many.) Other times, two phenomena that weren't understood well are explained as one common thing (Bacon showed that heat is a kind of motion; Newton showed that gravity explained both planetary orbits and ballistic trajectories; Maxwell showed that electricity and magnetism are the different aspects of the same phenomenon.) All of this is stuff that I have understood since high school, but viewing it this way gives me a hook to hang a few more things on. The rest of physics constitutes theories that I've been able to understand at a surface level, but which have never been integrated in any deep way. Smolin's framework makes it possible for me to hold a few more theories in my head and see how they give shape to the entire universe.

Einstein was responsible for the next three major unifications. Special relativity forces space and time to be interchangeable in order for the speed of light to be an observer-independent limit. (Mass and energy, too, must be epiphenomena of some more fundamental construct.) General relativity showed that gravity is indistinguishable from acceleration, and that space has no geometry independent of the mater and energy that it contains. These are still a little hard for me to grok completely, but I feel much more knowledgeable about them post-Smolin. Previously, I was satisfied with being familiar with the equations, even though I didn't really understand what they implied about the universe. Now I feel like I understand them as facts about the universe, though of course it's a stretch to claim I understand how they fit together.

Even with QED, QCD, supergeometry, and the two DSRs, I am much happier that I understand what they are theories about than I was before. I've read several books on the frontiers of modern physics, but I'd have been hard pressed to say, more than a month after putting each down, what they implied about the universe. With Smolin's help, I now feel like I understand what the point of most of these theories are, and what it would mean to bring them together.

Tuesday, March 27, 2007

Prometheus finalists announced

This year's Prometheus finalists have been announced. The links from the titles are to my reviews.

The finalists for Best Novel are: * Empire, by Orson Scott Card * The Ghost Brigades, by John Scalzi * Glasshouse, Charles Stross * Rainbows End, by Vernor Vinge * Harbingers, by F. Paul Wilson

And the finalists for Hall of Fame are: * A Clockwork Orange, a novel (1963) by Anthony Burgess * "As Easy as A.B.C.," short story (1912) by Rudyard Kipling * It Can't Happen Here, a novel (1936) by Sinclair Lewis * Animal Farm, a novel (1946) by George Orwell * The Lord of the Rings, a trilogy of novels (1954) by J.R.R. Tolkien * "True Names," a novella (1981) by Vernor Vinge

I haven't written reviews of any of the hall of fame nominees, though I've read them all. Perhaps that's a sign that I should read them again.

Saturday, March 24, 2007

Robert A. Heinlein and Spider Robinson: Variable Star

The author of Variable Star is listed as Robert Heinlein and Spider Robinson, but it's really a recently discovered outline by Heinlein that Robinson has turned into a novel. The story has a very anachronistic feel to it, with many heinleinian plot points (it appears to be set in Hienlein's Future History) but references to recent events and relatively modern mores.

I don't much care for stories with a reluctant hero, and Joel Johnston has to be dragged, kicking and screaming, through each of his life transitions. He's actually a fairly decent character in between, but the switch-overs are wrenching.

The story was a nominee for the Prometheus award, but wasn't chosen as a finalist. It doesn't have much to say about freedom or self-direction; it's not a cautionary tale; the governments are benign and consensual or required by circumstances (a 500 person starship has to have a captain and someone to keep the peace) and minimal, but in either case, neither something to fight against or to hold out as a model. The characters are pushed around by fate and circumstance.

The story takes so many hairpin turns that there's not much else I can say without spoiling the plot. Talking about anything after the first 50 pages would tell way too much about the most surprising development, and after that, things are pretty much pre-ordained other than the details. I'd rather read a real Heinlein juvenile, and make allowances for Heinlein's atavatistic viewpoint or a modern story by Robinson (with all the puns) than this mishmash.

Thursday, March 15, 2007

Would you Trade your Sense of Smell for a Longer Life?

Recent experiments on fruit flies undergoing Caloric Restriction seem to show that the effect of CR is reduced or eliminated if the flies are exposed to the odor of food (yeast in their case). That led to experiments in which the experimenters genetically eliminated the flies' ability to smell. They found a stronger contribution to lifespan from smelling the food than from how much the flies ate.

Would you give up your sense of smell if it meant living 50% longer? The question is only hypothetical at this point: replications in other species haven't been reported yet.

Saturday, March 10, 2007

F. Paul Wilson, Harbingers

F. Paul Wilson's Harbingers is a nominee for the Prometheus award. I understand the impulse to nominate the Repairman Jack novels for the Prometheus: Jack is a strong character who fights evil and eschews all contact with the government while living in New York City. His attitude toward self-help and antipathy to gun control also help his case. It's probably the fact that it's horror, and that both the cosmic bad guys and the cosmic okay guys are inscrutable that drives me away.

With this installment, I realized that there was another aspect that was bugging me. In the past 9 novels, little has changed about Jack's relationship to the two warring factions that are thoughtlessly interfering with Jack's life. Harbingers, on the other hand, contains several significant developments in that relationship. In fact, it reads like the second volume of a trilogy. Too bad it took Wilson 9 books (plus 6 others set in the Adversary world) to get us here.

But overall, I don't find the libertarian themes to predominate over the standard horror tropes. And inscrutable powers for whom we barely even qualify as pawns aren't much of a recommendation for a libertarian point of view.

In its defense, this book does have Jack standing up to the Ally after it attempts to take away what he most cherishes. But the negotiation ends with the Ally seeming to hint it won't hurt Jack's family for as long as he does what it wants. Not much of a recommendation.

Wednesday, March 07, 2007

Orson Scott Card: Empire

Orson Scott Card's Empire has been nominated for the Prometheus award. It stands a chance as a cautionary tale like Sinclair Lewis's It Can't Happen Here. The story covers a plot (with tentacles in the White House) to overthrow the government and bring about a left-wing coup. The action is intense, but the politics is strained. Like Lewis' novel, the point (as Card explains in an afterward) is to convince us that it wouldn't take much to turn our current heavily factionalized politics to open warfare.

The story reveals that far-left and far-right groups have been preparing plans in secret for years to take control of the government violently if it should become necessary (because the other side has gotten too much control.) The leftist radicals apparently have the advantage, since they have an extremely wealthy fanatical backer who has been funding the development of new high-tech weapons and staffing and training an army to use them. This part unfortunately reflects the fact that the backers of Card's project are game developers; the new weapons are several steps ahead of what the uniformed military has access to, but would play well on the video game consoles.

The viewpoint characters are sympathetic, well-trained special ops soldiers, and are patriotic to a fault. Their loyalty is to the nation and its legitimate leaders. The action is intense. But ultimately, the story falls short of being a cautionary tale. The motives of extremists on both side are hard to fathom; they want control of the levers of power to prevent the other sides extremists from doing something bad, but it's not clear what. After the conspirators take control of New York City and get sympathetic resolutions from a few state legislatures, they don't make any visible changes in anyone's lives.

At least Sinclair Lewis showed that the fascists who took over would have to suppress dissent brutally and ruthlessly in order to maintain control. In Card's novel, life goes on as before. At the end of the novel the viewpoint characters suspect the newly elected president of having helped orchestrate the entire coup in order to ensure popular support for his own election as a peacemaker. But they can't find any indication that he has dastardly designs to justify the conspiracy they are looking for.

The attempt at a coup and rebellion were short-lived, caused only a handful of deaths and a moderate amount of damage, and didn't have any impact on everyday life. As a cautionary tale, it's not much to worry about. If the protagonists hadn't done such a good job of protecting the nation, an extremist megalomaniac might have taken over the government, but Card's novel doesn't explain why that was something to worry about.

Tuesday, March 06, 2007

Conditional and Combinatorial Betting

After people have used Prediction Markets for a while and have gotten used to their ability to provide forecasts, they start thinking about different scenarios. Who would be the best Republican to face Clinton? How are the prospects for a market boom or crash effected by the winner of the election? How will poverty be affected by a proposed World Bank program? These kinds of questions can be posed in a number of ways using Prediction Markets. Markets can allow betting on conditional (if) or conjunctive (and) questions. Either one can be used to answer the what if questions, but they provide different choices to the bettors, and some make it easier for observers to decode the answers.

The easiest compound question to pose is a simple conjunction of two others. InTrade had separate markets in whether Bush would be reelected in 2004 ("BUSH"), and whether Osama bin Laden ("OSAMA") would be captured before the election. Justin Wolfers and Eric Zitzewitz asked InTrade to add a single combined contract that would pay off if both came true. Their paper, Experimental Political Betting Markets and the 2004 Election shows how the prices on these three contracts can be combined to show how one event would be likely to effect the other.

InTrade created three separate claims to cover combinations of the two base questions. They were "Bush wins election" (BUSH), "Osama is captured before the election" (OSAMA), and the combination: BUSH&OSAMA which would have paid out if both the others came true. Wolfers and Zitzewitz estimated the market's conditional probability by comparing the price of OSAMA with the price of BUSH&OSAMA. If the price levels were rational, the difference between the two prices had to equal the chance that Osama would be captured and Bush would not be reelected. Since the market price of BUSH&OSAMA was 91% as high as the price of Osama, they concluded that that represented the conditional probability. A weakness of this conclusion is that while investors and arbitrageurs have an incentive to ensure that the price of BUSH is correct relative to ~BUSH, (and OSAMA with respect to ~OSAMA), there's no bet that lets an arbitrageur exploit superior knowledge of the conditional probabilities.

Sometimes investors believe they know how one outcome will effect another, and want to bet directly on that linkage. If you were confident before the election that Osama's capture would raise the probability of Bush's reelection to 95% (above the level the the market prices implied), having the conjunctive bets didn't provide a bet that would have looked beneficial to you. You might think you could buy Bush&Osama (because you believe Bush's chances are improved if Osama is captured) and sell ~Bush&Osama (because this is the outcome your view says is least likely), but you'd lose both bets if Osama wasn't captured (which is an outcome your prediction doesn't specify.)

Conjunctive claims allow observers to deduce connections between claims, but since the investors aren't directly rewarded based on the conditional probabilities, they have little incentive to ensure that the implicit conditional probabilities reflect their understanding of the connections between the outcomes. In order to evaluate different proposals we have to look at what investors would spend up-front, and then compare the possible outcomes and how the investor's earnings change in each situation.

If Bush is a 60% favorite to be re-elected, and the market thinks there's only a 10% chance Osama will be captured before the election, the odds on the conjunctions might be:

 Bush reelectedBush defeated
Osama captured .09 .009
Osama free .5 .4

If you think Osama's capture would improve Bush's prospects to 95%, what should you buy or sell? Your prediction says that the ratio of Bush&Osama to ~Bush&Osama should be 19:1, but doesn't have anything to say about Bush&~Osama or ~Bush&~Osama. If you buy Bush&Osama and sell ~Bush&Osama, you can make the prices match your beliefs better, but you'll lose money if Osama isn't captured. In order to support conditional bets directly, market operators have to find ways to allow traders to buy positions without exposing themselves to risks due to the independent cases.

A contract that acts like a conditional bet directly (written as BUSH|OSAMA, pronounced as "Bush given Osama" or "Bush conditional on Osama") would pay off if Bush is elected, and return your investment if Osama bin Laden isn't captured. That gives investors the right incentive.

 Bush reelectedBush defeated
Osama capturedGain $1 Lose investment
Osama free Return investmentReturn investment

In order to support betting on conditional probabilities, the bets have to be able to return the investors' money in particular cases. I know of three detailed proposals that have this property. They are: betting on arbitrary boolean expressions, representing the complete cross-product of possible outcomes (providing a complete set of Arrow-Debreu securities), and using the independent claim as currency for purchasing the dependent claim. There are two additional suggestions that might work, but haven't been written down in sufficient detail to be sure.

Robin described and implemented Combinatorial Information Markets which represent probabilities and traders assets explicitly for all possible combinations of outcomes. Fortnow, Kilian, Pennock, and Wellman described how you might try to support bets on arbitrary boolean combinations of conditions. Their conclusion seemed to be that solving the general problem would be computationally infeasible. They didn't describe how to address the problems they found, but I think it's possible that a market that supported only binary combinations could be designed. And finally, Peter McCluskey built (and released as open source) USIFEX in 1999. It allows the user to use the coupons of the independent event as the currency. This combination allows traders to express conditionals directly. Unfortunately, that system didn't attract a user base quickly enough, and Peter stopped development soon after the initial release.

For an article on Decision Markets written in 1999, Robin Hanson suggested creating markets using assets that pay off in "units of A if B passes" (and "... if B doesn't pass."), and allow traders to trade the assets for each other. The price of A|B in terms of B (which can be built from component assets) expresses the conditional bet. Robin didn't explain how to set up a market in which people trade assets for assets and didn't describe how to let the users see how various combination bets would express the conditional claims they might have been interested in. (This is the first of the two incomplete suggestions.)

Robin's Combinatorial Information Market design uses a complex internal representation and can support arbitrary conditional bets. He built a prototype implementation that allows the user to explore these conditionals by choosing assumptions, and then adjusting probabilities in the resulting hypothetical situations. I wrote a prototype of my own in E. Neither prototype is more than a proof-of-concept that the institution works, and neither has been operated for any general market. The strength of this approach is that users can express conditional connections between arbitrary claims; this aspect has been shown to be effective in a laboratory experiment. Robin ran tests of this market after he proposed its use for PAM, and there were apparently no problems in running it with 6 traders estimating all outcome combinations for 8 events. The glaring weakness is that it doesn't scale well. It's not clear how to build a version that would work even with a market with dozens of questions and hundreds of users. I'll describe this market in more detail in a future post in this series.

Peter McCluskey built USIFEX in 1999. It works quite differently and doesn't seem to have the performance problems of the other proposals. The primary idea for supporting conditional trading is that you buy units of A|B using units of B as currency when betting on a conditional question. The effect is that when buying A|B, you end up with coupons of ~B as part of the purchase, and that's what ensures you'll be repaid if the independent event doesn't occur. USIFEX is open source, but it hasn't been maintained since it was released in 2000. The code was resurrected for use in the Swiss MarMix exchange, (AFAICT without making any use of the conditional betting features). The biggest weakness of Peter's approach, as I recall, was that it would have taken a lot of users to ensure that the conditional markets weren't extremely thin. A longer description of USIFEX is also in the works.

Todd Proebsting built an implementation of the Hanson design that works without conditionals. Dave Pennock wrote up a description of Todd's approach, focused on the Market maker. I intend to describe the implications of Todd's approach for betting on conditionals in a future post. (This is the second incomplete suggestion.) I think it might be straightforward to extend Todd's approach to support conditional betting without running into the exponential growth of Robin's solution. The drawback is that the market operator has to separately capitalize and enable every conditional question that you want the system to support, while Robin's approach enables all of them by default. It's also possible that Zocalo Open Source Prediction Market software would be compatible with this approach, where it's clear that Zocalo would require substantial modification to support the Hanson proposal.

Other Articles in this series

Thursday, March 01, 2007

Robert Pape: Dying to Win

Dying To Win , by Robert Pape, makes a reasonable case that suicide terrorism is primarily used by groups that perceive themselves to be oppressed in their home country by a powerful democratically governed foreign invader (usually with a different religion). The goals and intentions of the occupier don't actually matter very much, as long as the defenders feel that they don't have control, and can use the religious difference to demonize the invader. Pape marshals a considerable body of evidence to show that conventional wisdom is wrong: the terrorists play up religious differences, but aren't motivated by religion; the individual terrorists aren't poor or suicidal; and suicide terrorism is used against democratic countries (the goal is to convince the voters that the occupation isn't worth the cost.)

The book's thesis only explains a portion of what is going on in Iraq today. As far as I can tell, suicide terrorism aimed at the occupying powers is less than half of the violence currently occurring in that country; the rest is sectarian. Pape's thesis doesn't explain why roughly equal factions would use suicide terror against one another in an internal conflict. But I think the explanation of the attacks against foreigners holds up well. Unfortunately, only part of the terrorists' message to America is getting through to the American public.

The public understands that American soldiers are being targeted, but all the internecine violence obscures the message about foreign occupiers. Since some of the local factions are clearly more interested in a battle for control of the country after we leave, the violence against foreign troops looks like part of a strategy to maintain disorder. Major media haven't help Al Queda spread the message that all they want is for the foreigners to leave. Even if they had, the internal violence gives some Americans a reason to want to persevere, so we can help stabilize the country we destabilized.

Pape argues that the only responses to suicide terrorism that have stopped it in the past have been acceding to their demands (withdrawal) and ruthless violence against the terrorists and their community. He argues that one of the reasons this strategy is only used against democracies is that they are seldom willing to be sufficiently ruthless.

I wonder whether it wouldn't have been useful in this context if we had spent some effort ensuring that the history of the American occupation of Germany and Japan after WWII was heard in the Middle East. Those countries didn't lose their national identity; they got a lot of help rebuilding; and they came out of it much stronger than they went in. It may be too late for this message to be spread in the Arab world, where everything we say now is treated as propaganda.

Pape's policy recommendation is to remove active troops from the Middle East, while leaving enough deployed in nearby positions so that we could respond rapidly to new threats. This, unfortunately doesn't address the current situation in Iraq; leaving the country now would give the violent local factions unfettered ability to continue their mutual pogroms. If that isn't the kind of event we would expect to respond to from the off-shore position he recommends, what would be?

For the most part, the book was reasonably even-handed, given Pape's apparent prejudices, which he showed once or twice. He speaks of an American "Policy [...] to conquer Muslim countries" on pages 6 and 241, but otherwise sticks to analysis based on an extensive database of all known suicide terror incidents he has compiled at the University of Chicago. The last, short, chapter giving his policy recommendations is clearly separate, and readers can individually evaluate its merits.

Monday, February 26, 2007

Charles Stross: Glasshouse

Charles Stross's Glasshouse has been nominated for the Prometheus award. The theme of overcoming ubiquitous surveillance makes it a likely finalist and a possible winner this year.

The story takes place in an advanced post-nanotech world where the primary means for long distance travel is cellular deconstruction, data transmission, and reconstruction. In addition to that, you can edit your body and mind before reconstruction, allowing you to modify your basic body type or gender, remove signs of aging, or edit your memories. Unfortunately, this also means that anyone who controls the gates can control what comes out the other end.

Robin, our protagonist, is one of several people who are going through rehab—apparently their most recent life left them with some mental trauma, and the editing at their last reconstruction wasn't as complete as it should have been, so they are getting used to their newest selves and learning to integrate into mainstream society. Since someone seems to be trying to kill Robin (who has strong self-preservation skills and instincts, but doesn't remember why), the choice to accept an invitation into an anonymity-enforcing experiment in recovering information about a lost historical period makes sense. The historical period is ancient earth; really a Hollywood-based view of 1950s-1990s America, but with many details elided, and the entire period mixed together in one giant mish-mash of the experimenters' guesses about why the stereotyped sex roles could co-exist with various anachronistic technologies and mores.

"In order to study the emergent properties of the society" the experimenters are constructing, the subjects are constantly monitored and rewarded with points for remaining in character, and lose points (both individually and for their cliques) for arbitrary behaviors the experimenters want to discourage. Some of the participants quickly adopt the point system as their primary driver of value, while Robin and a few others find unseen ways to fight back. Eventually, Robin discovers a cell of others who want to stop the experiment and/or escape.

The story is well-told and interesting, with both action scenes and psychological studies of the characters. The conflict is engaging, and the elaboration of the background (I haven't given it all away here) is rolled out in a plausible sequence. The exploration of how modern society will look to far-future societies is entirely plausible, with or without intentional culling of the historical records. Stross's characters have a believably accepting attitude to gender- and bodyplan-switching, and their reactions to an attempt to impose a cartoon interpretation of 1950s gender roles is convincing.

There aren't any obvious governments, but several factions are struggling to become the de facto monopolists on political control and the use of force, either locally or throughout the connected polities. The idea that societies that can communicate as easily as they do throughout the Invisible Republic might still maintain distinctly different political systems is interesting. The implication that it might be stable as long as no one manages to subvert the gates that enable cheap commerce is intriguing.

Saturday, February 17, 2007

Sheri S. Tepper: Six Moon Dance

Sherry Tepper's Six Moon Dance is an intriguing fantasy. It starts out seeming to be an investigation of a society with unusual sex roles (half the female babies on Newholme die as infants, so women have unusual power. Men are seen as the weaker sex, and male concubines are common; Mouche, the viewpoint character, will train to be one). The story slowly morphs into a deeper exploration of the interaction between a bizarre quasi-human society, and two interesting alien organisms, mediated by the Great Questioner, a cyborg with her own problems. Each has been changed by their interactions with the others.

Humans have only inhabited this world for a few hundred years. The first settlers didn't notice the native life (they were hiding until they figured out the settlers intentions), which put them in a bind because the Council of Worlds enforces their version of the Prime Directive harshly. The native life has some rather fantastic powers: budding off individuals who can live a separate life for a while and then reabsorb, returning their memories to the collective.

The story arises because the Questioner (the investigator and enforcer of the Prime Directive) schedules a visit at the same time as Newholme's periodic geologic upheavals start again in earnest. The natives have dealt with the problem in the past (it's partly of organic origin and intricately related to both the themes of multi-species intertwining and strange sex roles) but need more help from the humans this time around, since their presence has disrupted their normal approaches. But if the local humans are to escape punishment, the Questioner mustn't notice the shenanigans.

Of course, the Questioner has her own resources, and her job is to be suspicious, so everything unravels. But along the way, this is more than the story of an investigation, and Tepper describes events and people very poetically. Here are a few excerpts to give a taste:

Questioner has drafted two young dancers to help her with the investigation on Newholme, and as they were still struggling to find their identities, her intervention has interrupted their progress. Gandro Bao has trained as a Kabuki dancer, which has given him some sex-role confusion (excuse his broken English, please.) The other dancer, Ellin Voy has identity issues since she found out she is a clone raised to be a dancer just like her mother and her many sisters.

"So, I am being confused, and some days I am looking at face in mirror and thinking, who is this? Is this male or female? Is this real person or only actor? ... So when I am twelve, ... and deciding I am whoever I am wanting to be! Who I am choosing to be!"
"But that's just it! I can't choose who to be! I never had a choice!"
"You cannot choose to be horse, or fish, or tree, no. But it is like this. You are like small seed, and this ship is like big wind, and it is blowing seed from small plant far, far away where is no other such plant. And plant is not saying, 'Oh, oh. I cannot be oak tree, I cannot be bamboo, I cannot be cactus, I have no choice.' Plant is not so silly as that. Plant is putting down roots of own self and growing! And while it is growing, when things are difficult, it changes a little bit, so when it is grown, it is not exactly like the plant it was coming from. It adapts."

Near the end of the book, Mouche is consoling the Questioner:

"the true story of any living thing has pain in it, and life has to be that way. Curiosity is a good goad, but pain is a better one. It is pain that moves us, that makes us learn how to cure, how to mend, how to improve, how to re-create. Inside all of us, even the happiest are memories of pain. ... Each of us cries that we are lost. We ask the darkened room, who are we? And we demand easy answers: I am my father's son. My mother's daughter. A child of this family, or that."
"That's the nature of mankind," she agreed.
"True, but Corojum had an answer that is equally true, and I like his better! We are made of the stuff of stars, given our lives by a living world, given our selves by time. We are brother to the trees and sister to the sun. We are of such glorious stuff we need not carry pain around like a label. Our duty, as living things, to be sure that pain is not our whole story, for we can choose to be otherwise. As Ellin says, we can choose to dance.

The part about being driven by pain doesn't resonate with me, but I liked the way the story illuminated the exhortation to choose.