lucaspa

Better to read Dennett. Natural selection is an unintelligent process to give design. It is an algorithm to get design. That is, follow the steps and design is a guaranteed outcome. So, yes, plants and animals are designed. But designed by natural selection.

Yes. The competition for scarce resources is what "concludes" that a trait is suitable for that environment. Look at natural selection as a design competition. The environment sets the design problem. Such as: what design will allow a water predator to move thru water fast enough to catch and eat prey? Each individual is a possible design for that problem. BUT, there are far more design entries than the environment can support. So the individuals/designs have to compete for the scarce resources: in this case, prey. Those designs that are better win and those designs that are worse lose. Now, the key is that the winners reproduce and their offspring inherit their designs. But the offspring also modifiy the designs due to variation. So now you have a competition between the modified design in the next generation. Again, not every design can win. The better designs win and the poorer designs lose. And so it goes generation after generation after generation. An accumulation of design modifications. In the example I gave above, physics and the necessity to bite and hold prey means that there is one general design for a water-borne predator. This is why sharks, ichthyosaurs, and dolphins look very similar. BUT, the particular starting point of design (land animal for dolphins) and chance in the types of variations thrown up, means that there are differences. For instance, since dolphins have a modified running motion for swimming (since they started out as runners), their tail fin is horizontal. And dolphins born with a tail fin not horizontal would not go as fast as those born with a horizontal tail fin. 1. There is not a SINGLE interaction with the environment. There are multiple and simultaneous interactions. We tend to look at the few simple interactions because they are easier to understand. But most of the time there are contradictory interactions and natural selection must find the best compromise design. Also, there is always a cost-benefit analysis. 2. What do you think is "micro" and "macro" mutation? Some mutations are in Hox developmental genes and can have a huge effect. For instance, change one base in the Ubx gene and you go from multiple legs to six legs or the reverse. Or change the Manx gene and either get or lose a complete tail. But whether such radical changes between two generations happen during evolution is doubtful.

I'm one of those that disagree. I'm afraid the effect will be negative. People don't understand that controversy like Smolin is stirring up is common in science. They will just look at this as another reason to think science is unreliable and scientists don't know what they are talking about. I wish Smolin and Woit had confined their efforts to forums restricted to the physics community instead of going to the general public I'd like to be wrong.

Let's test this. If the book were targeted to the physics community, it would have a lot of mathematics in it. But it doesn't; instead the reviews all comment on the personal touch and how Smolin weaves his personal life into it. Such a style is designed to reach a non-physics audience. If the real discussion is the state of physics and string theory, then physicists don't need Smolin's life story and anecdotes, do they? Besides, the physics community isn't large enough to put the book in the Bestsellers list! No, if Smolin wanted to reach the physics community, there are better forums. Review articles in Phys. Letters or Phys. Review, for starters. Or an article on the physics online journal http://www.arXiv.org.

First, I tend to agree with you about building more nuclear plants. But we can't minimize the problems. The difficulty with a breach like Chernobyl is that if one occurs at, say, the plant just up the river from NYC, you put tens of millions of people at risk. In that case, any failure rate, no matter how small, becomes intolerable. And you put the plants near the cities so that loss from transmission is reduced. Second, the problem of rogue states is very relevant. Remember, the use of petrol is greatest among the developing world, and that's where you have the rogue states. Since hydrogen is so tough to transport, Iran is going to want to have its own hydrolysis for its hydrogen vehicles. And that means nuclear plants in Iran. And we know how well that is working out right now and how well it has worked out in N. Korea. The chance of nuclear weapons being used increases with the number of states that have them. The odds that you will get ONE irresponsible state approaches 1. And, with several states (including the probable opponents) having nuclear weapons, then you get the probability of a nuclear exchange and nuclear winter. That's as catastrophic as global warming, right? Of course, there is also the problem of security. The more nuclear plants, the more difficult to guard them all. And this the temptation for terrorists to attack a plant -- either to cause nuclear accident or to get their hands on the material. Just a few ounces of plutonium put in the reservoir of NYCs water supply, and the deaths are in the millions. Yes, plutonium is that bad a poison. Third, the problem of waste disposal is such a long term problem. Isotopes with half-lives of millions of years. And don't forget the plants themselves. After 50 years of operation, even the pipes and walls of the plants are slightly radioactive as neutrons convert some of the atoms to radioactive isotopes. Didn't you read the problems of transporting H2? You can't put the power generation in "one place". You have to have electrolysis plants everywhere, and that means the power generating plants everywhere. What you are saying is that environmental downside to nuclear plants is less than the environmental downside of coal or other petrochemical generating plants + the release of greenhouse gasses by cars. I agree with that, but it's not a slam dunk. It depends on how serious you think global warming is going to be. Also, like it or not, nuclear plants are expensive. The safety improvements that you so blithely pass over add exponentially to the cost. That is, getting a 1% improvement in safety from 98% to 99% doesn't add 1% of cost, but multiplies the cost by several fold. For the foreseeable future, coal is SOOO much cheaper than nuclear power there is no way to economically do what you propose.

Yes, and that was with an FTL drive. Unless the FTL drive was instantaneous to anywhere, even FTL has a finite speed. I discussed this in a reply to your previous post that the inner worlds could not ship their excess population out past the colony worlds. So you either have war with the colony worlds for settlement or the inner worlds collapse and the population (and civilization) is drastically reduced thru war and/or starvation. Now, since it is known that the inner words are inhabited and their location is known, it would be easier for the outer colony worlds to ship their population back to the inner worlds rather than expand outward. In that case, you get an optimum sphere size of colonized worlds and continual shifting of population within the sphere -- which both you and I have pointed out before, but SkepticLance ignored. Right. As far as I can see, none of SkepticLance's reasons for expansion are inevitable. All of them have counteracting processes that would eliminate the motive/expansion or reduce it to a crawl such that the expansion has not gotten even close to earth yet.

What you are doing is changing the argument in the face of falsifications. Another way of putting it is that you are introducing ad hoc hypotheses to try to save your hypothesis. Remember' date=' your claim depend not just on going "interstellar", but having a [i']sustained, continued [/i]colonization program using sublight transportation such that one of the species would have reached earth. You need a motive that gives you continued colonizations/explorations. So far none of the suggested motives have withstood critical examination to give you the certain, sustained colonization. Accept that. Yes, you can maintain possibility, but the arguments against that are just as strong or stronger. Conclusion: there could indeed be a million technological species in the galaxy but, if we are limited to less than 0.5c, there are very good reasons why none of them have made it to earth. You took out a key phrase. I put it back in italics. And why would those landfills be on the surface? How much of our planet has rocks from a billion years ago on the surface? C'mon, do some research and give us some data! Yesterday the news was that a new oil well in the Gulf of Mexico had come online. It was 20,000 feet below the surface. So, yes we could be living on their landfills -- but they are 20,000 feet below us. OR ... those landfills have already been eroded. 500 million years ago the Appalachians were 40,000 feet tall. What do you think happened to them? I would think you would leap at those artifacts, since they are support for visitation. However, would the artifacts still be here even a million years afterward. I've already pointed out methods of degradation. What artifacts do you think would be immune and would last for a million years, much less a billion? But the economic, social, and biological consequences of unrestrained reproduction are not fiction. Think of the novels as a thought experiment and speculation. After all, it was YOU who pointed out that we are engaging in speculation. So Niven and Pournelle's speculation based on economic and biological realities are relevant. You just don't want them to be because those consequences refute your conclusion. That's not a good enough reason. You proposed population pressure as the prime motive for colonizing the galaxy using ships at 0.2c. But the speculation is that such population pressure is more likely to lead to cycles of trying to feed the population followed by catastrophic war for resources, and then back to barbarism. Now, instead of trying to ignore the speculation, try to show why it is inaccurate. I'm saying that if such a species exists, then economics will ensure that it controls its population before it gets critical and will remove the motive for colonization. This is where the studies on humans -- who fit your profile -- come in. Increasing wealth causes control of population -- because the individuals "must" control their population to retain their wealth. And a civilization technologically advanced enough to make the generation ship you propose will be wealthy. Thus, already controlling their population. And there goes your motivation. The planet is not overcrowded and there is no population pressure for colonization. Now, you propose a 50 years hop of 4 light years. BUT, we don't know that Alpha Centauri has planets. Is it even theoretically possible to detect an earth-like planet at that distance? I doubt it, but you can do the research to show me wrong. So, the ship can't just be engineered for that hop, can it? If Alpha Centauri doesn't have planets, then they have to keep going ... for they don't know how long. You can't engineer for that. You have to control population. The way to determine habitable planets would be to send a probe. That's at least 50 years out and 4 years transmission time back ... assuming nothing bad happens to the probe. So, 54 years before launch of the probe until you even know if you can launch the colonization mission. Economically, there is no use even building a ship until the info is back and is positive. So now you have construction time. By this time, any political or social motivation for colonization has probably gone away.

And, if pollution continues, you will be! However, some of the pollutants are greenhouse gasses. Since burning coal is still the cheapest form of generating electricity, even if you use hydrolysis, that means burning a lot of coal to make the electricity to make the hydrogen. And global warming is indeed global. How do you store electricity? Batteries are the only method I know of now. Of course, making hydrogen and then using hydrogen fuel cells would be another method of "storing" electricity. But now you have the problem of transporting the hydrogen. And that's not trivial.

Besides the operating safety issues and the possibility of releasing large quantities of radioactive and toxic materials a la Chenobyl? The tendency for rogue governments to use the plants to make bomb-grade uranium or plutonium (as Iran is suspected of doing)? How do we dispose of the spent fuel rods -- highly radioactive and toxic? And what do we do with the radioactive plant itself after it's worn out? Remember, plutonium is several times more toxic chemically than cyanide. Other than all these problems, there's nothing "wrong" with nuclear plants.

But the problems are much bigger with hydrogen. "That is, if such a pipeline were even practical to build. Given hydrogen’s low density, it is far harder to deliver than, for instance, natural gas. To move large volumes of any gas requires compressing it, or else the pipeline has to have a diameter similar to that of an airplane fuselage. Compression takes work, and that drains still more energy from the total production process. Even in this instance, managing hydrogen is trickier than dealing with other fuel gases. Hydrogen compressed to about 790 atmospheres has less than a third of the energy of the methane in natural gas at the same pressure, points out a recent study by three European researchers, Ulf Bossel, Baldur Eliasson and Gordon Taylor. A related problem is that a truck that could deliver 2,400 kilos of natural gas to a user would yield only 288 kilos of hydrogen pressurized to the same level, Bossel and his colleagues find. Put another way, it would take about 15 trucks to deliver the hydrogen needed to power the same number of cars that could be served by a single gasoline tanker. Switch to liquid hydrogen, and it would take only about three trucks to equal the one gasoline tanker, but hydrogen requires substantially more effort to liquefy." "Among hydrogen’s disadvantages is that it burns readily. All gaseous fuels have a minimum and maximum concentration at which they will burn. Hydrogen’s range is unusually broad, from 2 to 75 percent. Natural gas, in contrast, burns between 5 and 15 percent. Thus, as dangerous as a leak of natural gas is, a hydrogen leak is worse, because hydrogen will ignite at a wider range of concentrations. The minimum energy necessary to ignite hydrogen is also far smaller than that for natural gas. And when hydrogen burns, it does so invisibly. NASA published a safety manual that recommends checking for hydrogen fires by holding a broom at arm’s length and seeing if the straw ignites." Quotes from same article as before

You are thinking in terms of generating electricity. Instead, think of pollution in getting hydrogen from coal. However, even in terms of hydrolysis, do you seriously think that renewable energy sources such as wind or solar are going give enough electricity to get the hydrogen you need? Remember, we use about 13 of million barrels of oil a day just in the US for fuel for cars and trucks. Think of how much hydrogen that is. "Hydrogen is also about five times as expensive, per unit of usable energy, as gasoline. Simple dollars are only one speed bump on the road to the hydrogen economy. Another is that supplying the energy required to make pure hydrogen may itself cause pollution. Even if that energy is from a renewable source, like the sun or the wind, it may have more environmentally sound uses than the production of hydrogen. ... "Hydrogen could be derived from coal-fired electricity, which is the cheapest source of energy in most parts of the country. Critics argue, though, that if coal is the first ingredient for the hydrogen economy, global warming could be exacerbated through greater release of carbon dioxide. Or hydrogen could come from the methane in natural gas, methanol or other hydrocarbon fuel [see illustration on page 72]. Natural gas can be reacted with steam to make hydrogen and carbon dioxide. Filling fuel cells, however, would preclude the use of natural gas for its best industrial purpose today: burning in high-efficiency combined-cycle turbines to generate electricity. That, in turn, might again lead to more coal use. Combined- cycle plants can turn 60 percent of the heat of burning natural gas into electricity; a coal plant converts only about 33 percent. Also, when burned, natural gas produces just over half as much carbon dioxide per unit of heat as coal does, 117 pounds per million Btu versus 212. As a result, a kilowatt-hour of electricity made from a new natural gas plant has slightly over one fourth as much carbon dioxide as a kilowatt-hour from coal. " But this isn't the end: "When natural gas is cracked for hydrogen, about 40 percent of the original energy potential is lost in the transfer, according to the DOE Office of Energy Efficiency and Renewable Energy. Using electricity from the grid to make hydrogen by electrolysis of water causes a loss of 78 percent." So, since most electricity is generated by coal-fired plants, that's a lot more release of greenhouse gases to make the hydrogen because the process of electrolysis is so inefficient. All quotes from "Questions about the Hydrogen Economy" in Scientific American, May 2001. BTW, when I mentioned binding metals to hydrogen for storage, my fuzzy memory was also thinking of metal hydrides as a way to store hydrogen. That's also in the article.

The plant is Wyoming is the one converting coal to hydrogen. It is that process that produces the pollution. It's not the generation of the electricity that is the problem; it's the production of hydrogen from coal. Now, if you can get power to do electrolysis on the scale needed for all the cars out there, then that is a different story. But the problem so far is that no power source generates that much electricity. So instead you use less power and get hydrogen from the huge reservoirs of coal -- hence Wyoming. But that gives you lots of pollution -- both air and water. BTW, if you are generating hydrogen by hydrolysis, then the plant is on the shore of an ocean. After all, you don't want to use fresh water -- that too is a scarce resource and getting scarcer.

Still doesn't tell me if the method is valid. Walk me thru why this isn't apples and oranges and the results are not coincidental. Irrelevant to my point. You are talking larger "waves". But the "waves" in QM are not the same as waves in classic theory. So to say that they (the waves) are equivalent is wrong. REmember your claim: that the waves in QM are the same as "cosmic waves". But since "waves" isn't being used in the same way and isn't the same phenonomon in QM and macro observations' date=' you can't make them be the same. Also you still haven't told me what waves are observed for the "universe". Irrelevant. I am addressing the use of language. You are saying "nucleus" and "shell". We are not discussion the structure of quarks themselves, but whether the composition of baryons corresponds to a nucleus with an outside shell -- which is the structure we see in atoms with a nucleus and a shell of electrons. Are you saying there is an equivalent structure in baryons? If not, then don't use "nucleus" and "shell". Again, irrelevant. You didn't address my point. To address my point you have to show that you are not just defining things to be the way you like. That there really is a nucleus and shell, not just defining them that way. That the universe does have classical waves, not just defining that it does. Also, "producing a theory that matches experiments" is the same as "accurately predicts". Those are 2 ways of saying the same thing. Yet one you call "science" and the other "mathematical philosophy". You are doing emotive work, not looking at what really is and what is really being said. And doing emotive work is not doing science. No wonder you have to hawk your theory on the Internet and not put it up for peer-review.

Being contradicted by the data. That's the ONLY reason to discount an opinion within science. We learned this with Galileo. It was his obnoxious, unprofessional, unproductive, insulting, and childish attitude that got him in trouble and caused his fellow scientists to bring charges against him. Now, all the qualities you named can lead you to suspect that the data contradicts him. After all, if the data were on his side, he needn't resort to those tactics. However, you still have to show, by the data, that the ideas are wrong.

That isn't how the article described it. The pollutants can't be scrubbed out. They are just going to be emitted. It's just that they will be emitted from a plant in Wyoming instead of in LA. Now, since the entire world is our "doorstep", I don't see how this helps. Yes, the smog in LA is less, initially, but then the entire planet becomes LA. This is progress? What "nasty gases"? The plan would remove the CO2 -- the idea is that the algae convert it to sugar and oxygen thru photosynthesis. I know. I said we needed it, not that we were going to get it. I stand corrected. I misremembered the role of platinum in fuel cells. It's not to store hydrogen, but provide a catalytic surface for the electrochemical reaction. http://www.howstuffworks.com/fuel-cell.htm Cars will have to have the high pressure storage, which means some leakage. Hydrogen doesn't need a crack -- it is small enough to diffuse thru a metal. But the leakage is going to be small compared to the amount of hydrogen used by the car.

Niven and Pournelle thought the matter out carefully. They always do. You "do not believe it for a moment" because it goes against what you want to believe. In the biological and physical situation postulated, there is no way for the Moties to get out of their system by sublight. Their population growth means that there aren't spare resources available to build a generation ship. Any Master trying to build one is going to either 1) be conqueored by a neighbor who puts resources into the military instead of a generation ship or 2) the resources are needed to feed and provide the other necessities of the expanding population. The tramline system of faster-than-light is immensely cheaper and it is relatively cheap to build a ship to do that. However, due to the special spacial circumstance in the novel, the Moties couldn't use it (they came out inside a star). But we are discussing a universe where faster-than-light is completely impossible and species are restricted by physics to sublight. In that situation, the economic situation facing the Moties would apply to ANY species unable to control their population. You forgot the modifications to enable it to survive interstellar debris. However, as I pointed out, any species building a Dyson swarm has no motivation for going interstellar. You ignored my extensive discussion of that point. For one thing, it is going to take millions of years to exhaust the available living space offered by the swarm. Just think of the surface area! Those city habitats are going to have, in their volumes, billionsof times the surface area of the earth! For tens or hundreds of millions of years, whenever population gets too high in a ship, just build a new ship and put it into orbit next to them. Only when the entire swarm is such that it fills all available orbits around the sun will the species even begin to feel crowded. I see you've just tried to introduce a new motive. Sounds like you are beginning to see the fallacy of the "population growth" argument. However, within the system, they don't have to GO anywhere. Just make a new ship and put it into orbit. In effect, they are already in their "promised land". Your argument only works until all available orbits are taken. Also, notice that you now have the whim of individuals, not an inevitable reason for expansion. Now, also remember, in order to undertake the interstellar trip, they must have population control. Otherwise they will starve or use all the breathable air. Between the stars, there is no source of new air -- no recycling system can be perfect (second law of thermodynamics). So what you have is all you've got. Population growth exhausts those resources and everyone dies. So, in order to even consider an interstellar trip, they have a means of controlling their population. BUT, this means that the time to filling all the orbits in the Dyson swarm gets stretched out even more. Instead of tens of millions of years, it may be billions of years or never. They may never get all the orbits filled. Instead of an inevitable expansion, you are down to another fraction: those species who have such an adventurous spirit that a whole city habitat will decide to invest in the danger, unkowns, and cost of conversion to take one of the city habitats on an interstellar exploration and colonization effort. Nope. Not certain at all. After all, over 2 billion years, very few species will have even filled their Dyson swarm orbits. Wait a minute. In order to find the materials to build enough ships to have a complete Dyson swarm, you need the raw materials and all the planets in that solar system will go into the effort. The atmospheres for the necessary gasses and the body of the planet for the structure of the ships. In which case the it takes even longer to have population pressure! We are assuming filling a hollow sphere of approximately Earth's orbit. If you expand that volume, then you correspondingly increase the area of living space. So, you have abandoned the motive of population pressure. Now you are talking about economic and adventure motive. Notice that people in Europe aren't emigrating anymore. Why? The economic and political motives are gone. There is enough wealth and political freedom so that people are content where they are. Similarly, people don't emigrate much from the United States. Emigration is from places that are poor and/or have political problems. But, a civilization able to build a Dyson swarm is technologically advanced. This means that everyone is going to have enough wealth. The political aspect is taken care of with people having their own city habitat ships. Don't like the political system you are under? You don't have to build a ship to go to the stars, just build another city habitat. And you can start out small and add on later. A LOT cheaper than building a generation ship. So, this leaves adventure. However, even adventurers had economic motives of greater wealth. Columbus wasn't exploring for the sake of exploring -- he was looking for a new route to the spice islands. How is this achieved by a one-way interstellar colonization trip? You already have wealth at home. If you desire more, there is opportunity there. If you want danger, work on the Jupiter type planets mining material to build new habitats. All in all, any civilization that is capable of building in-system city type habitats has no motive for interstellar colonization. It doesn't even have motive for interstellar exploration. There is nothing out there that would convince people to invest the money in a ship that is never going to come back and realize a profit on the investment.

The review did seem a bit strident and intolerant to me. String Theory is not as rock solid as Motl makes out. He must have had a cow when he saw: 5. Kaku M, Testing string theory. Discover August 2005 http://www.discover.com/issues/aug-05/cover/ There are also papers in physics journals that I've seen that indicate that the predictions made by String Theory are not being found. Instead of stating Smolin's remarks on how to reform science, I wish Motl would have quoted Smolin instead of making these statements: "In the sociological part of this book, Smolin complains that no one takes him seriously and tries to paint the mainstream physics community as a group of evil people. Also, he proposes "cures" for the things that he views as "problems". This includes new ethical standards of the science community. For example, one of his rules says that conclusions must be accepted by everyone if their author is a person of good faith. Another rule, apparently applied to the other theories, says that they must first present a full rigorous proof. " These are very serious charges. They need to be documented by quoting Smolin instead of just saying that Smolin said this. I personally think Loop Quantum Gravity is a cool idea. Don't know that it is correct, but then I don't know that String Theory or Randall's 'branes are correct, either. The data simply isn't there to say one way or the other. But scientists do get overly emotional sometimes when defending and attacking ideas. Look at the Gould vs Dawkins animosity. Not every scientist is as rational as Milgrom: "As its inventor, I would like it [MOND] to be a revolution, but I look at it coolly," says Milgrom. "I will be very sad, but not shocked if turns out to be dark matter." C Seife, Radical gravity theory hits large scale snag. Science 292: 1629, June1, 2001

Again, this is good because ... Implicit in your sentence, but unstated, is that Smolin's book is somehow exceptional. Why?

1. Moving the pollution doesn't really solve anything, does it? Since it is atmospheric pollution, it is going to get to you eventually. What we need is fusion power. Then we would have enough cheap electricity to hydrolyze water for hydrogen. Until then, the current methods of cooking coal just makes more pollution. 2. There are ways now to keep the hydrogen bonded to porous metals -- titanium is one, I think. Thus, you don't really have a pressurized gas in a fuel cell like was in the bags of the zeppelins. No more danger of explosion than you have with gasoline powered cars -- maybe less.

We use gasoline because it combines with oxygen (a process known as combustion) and combustion gives off heat and forms a gas that expands. This expansion moves the cylinders. Now, think about it. How is water formed? It is the end result of combustion! That is, water is formed by hydrogen burning with oxygen. Thus, all the heat has already been given off! In hydrogen fuel cells, the end result is water. And electrolysing water takes far too much energy -- think of how much energy is given off in a hydrogen flame -- so separating the hydrogen and oxygen requires at least that much energy. Where does that energy come from? Currently, the idea is to heat coal in the absence of oxygen so that hydrogen is given off. That will be the source of hydrogen in fuel cells. A problem is that this process gives off more pollution than burning gasoline in cars. The politicians like Bush who push the scheme hope you are too dumb to realize this. Yes, less pollution in cities where the fuel cells are used, but more pollution overall that comes from the plants making the hydrogen. Scientific American had a good article on this about 2 years ago.