SGU Episode 252
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Introduction
You're listening to the Skeptics' Guide to the Universe, your escape to reality.
S: Hello and welcome to The Skeptics' Guide to the Universe, today is Wednesday May 12th, 2010, and this is your host, Steven Novella. Joining me this week are Bob Novella,
B: Hello
S: Rebecca Watson
R: Hellooo
S: Jay Novella
J: Helloooo
S: Evan Bernstein
E: I can't even try to top that, so I'll just let that be.
S: Ok
B: I hate you all
S: And joining us as a special guest rogue this week, Massimo Pigliucci
M: Hello there
S: or Mass-imo, as we like to call him
E: Mass-imo
S: Massimo, you have a unique distinction-
M: Alright!
S: -for our podcast, in that-
R: Just one
S: Just one. If we harken back to June 7th 2005, episode number three, you were our first interview on the show.
B: Oh, cool
M: I was pretty young that time
(laughter)
B: Weren't we all
S: It was five years ago, yeah
B: Rebecca wasn't even born yet
R: (laughs) Hey
(laughter)
B: Steve, isn't 'unique distinction' redundant?... I'm just saying
S: No
R: He's just saying it before hundreds of listeners have the chance to say.
E: I was going to say, that's for the listeners to decide.
News Items
Nonsense on Stilts (1:33)
S: So Massimo, part of the reason you're joining us at this time, is that you have a new book coming out called 'Nonsense on Stilts'. And I believe you said the release date will be May 15th, which is the day this podcast goes up, correct?
M: How did you know the book was coming out? Oh, I told you, right.
S: Yes, you told me
(laughter)
S: You said (desperately) "Please have me on your show so I can plug my book!"
M: That's exactly right. Yes, it's be May 15th, although from what I hear, it is already available on Amazon and people have been ordering it.
J: What's it about?
S: Yeah, tell us about it.
M: Well the phrase 'nonsense on stilts' is actually an old one, it goes back to philosopher Jeremy Bentham, who used it to indicate things that he thought were atrociously idiotic or stupid. So it was not just nonsense, but really, really tall nonsense, nonsense walking on stilts. In particular, however, the book is about the complexity of the landscape that separates science from non-science, from pseudoscience. As you guys know, in philosophy, that's known as the demarcation problem, Karl Popper thought he had a very easy answer to what distinguishes science from pseudoscience: if a hypothesis or statement is falsifiable, then it's science, it's scientific; if it's not falsifiable, it's not scientific. Turns out that that was a little bit too simple, and so the book explores the idea that in fact there is a continuum between things that are definitely and clearly pseudoscience, let's say astrology or intelligent design, things that are clearly and definitely science, let's say fundamental physics, or evolutionary biology. And then the really interesting stuff that is in between, which we don't know what to make of, or it's hard to make up our mind about whether it's science, or to what extent it is science, or not
S: Give me an example of something you think is right in the middle.
M: Well, for instance, at the moment, string theory would be right in the middle. Meaning that it is, as you know, it's fundamental physics, which is supposed to address a major problem in physics, which is the apparent contradictions in some realms of obligation between quantum mechanics and general relativity. Now, those are two of, arguably, the best established theories in science, it's hard to imagine one of them is 'wrong', let alone both. And yet, when applied to certain problems, such as what happens inside black holes, or the very origin of the universe, they tend to give us very different answers. So string theory is one of several attempts that physicists have made over the last three decades or so to reconcile quantum mechanics and general relativity, and, as it turns out, it's a beautifully developed mathematical theory, it's the mathematical constructions are, which I don't even pretend to understand, are in fact, I'm told, are very nice, very interesting, and very convoluted, except for the little detail that so far at least there is no way to test empirically any of the claims of string theory. So certain theories are compatible with everything we know about physics, but it hasn't made any predictions so far. They are critically untestable, which raises the question: if something, no matter how beautiful it is, if something does not make any critically testable predictions, is it science?
S: Yeah, We've had this discussion before with Michio Kaku,[1] and I've heard other physicists discuss it. This is something about which theoretical physicists can disagree. The problem that I heard, was not so much that it doesn't make any predictions, that it makes too many predictions, there are so many different formulations of string theory, that even if you disproved one of them, there's a thousand others lined up ready to go. So it can't be constrained, in such a way that it can't be falsified.
M: Right. To some extent actually they're both true. At the moment, at least, the theory in any form doesn't make any predictions outside of what is already known, in other words, it makes a lot of post-predictions
S: Right
M: Right? So it explains a lot of things we already know, but that's true also of other theories in physics, such as the standard model. It is also true that string theory comes in hundreds and hundreds of different forms, in fact, possibly thousands of different forms, so it's really a family of theories. And there doesn't seem to be any way, even in principle, that no matter how good we get in the near future at providing new data, you know, gathering new data in fundamental physics, it doesn't seem possible, conceivable, that we will be able, ever, to discriminate between hundreds or thousands of different versions of the same theory.
S: Right
M: So that seems to be a big problem. Now, it doesn't mean necessarily, of course, that string theory is wrong in any particular sense. In fact, one of the books that famously criticizes the theory, which is by Peter Woit, is a mathematician and physicist, it's entitled 'Not Even Wrong'.
S: Yeah, right.
M: Meaning that we don't know.
S: Yeah we're not even wrong, we're suggesting it's not even a scientific theory.
M: Right
S: You have to be scientific in order to be wrong.
M: That's right
B: Well Brian Greene, I heard a talk by him, and he said it's really not accurate to call it a theory, he refers to it as more of a hypothesis.
M: Yeah, That gets in to interesting- well, I was going to say- I was going to use the word 'self-restraint', but perhaps that's a little unfair. I mean, it gets to 'what is the difference between a theory and a hypothesis?'. Now, in philosophy of science, in theory is a general, broad construct, such as quantum mechanics, for instance. An hypothesis is a specific kind of- either a subset of a theory, or a specific type of predictions that are made from that theory. So, if Greene wants to consider string theory a hypothesis, in that sense that would mean that it's not as comprehensive, and not as much as the ultimate theory of everything that it's supposed to be. But I don't think that's what he meant, I think he meant that's just a conjecture, it's just something that's in the workings. And that is fair, except that, as another critic of string theory pointed out recently, Lee Smolin who wrote a book entitled 'The Trouble with Physics', string theory has been a working hypothesis for about three decades, and the question at this point is fair to ask, you know, how much longer is it gonna be working before it actually produces results that are seriously and critically testable?
S: Right, but I think the counter to that is 'it's just really hard, so what if it takes 100 years, that doesn't mean it's not science. It just means this is intractable given our current our current state of science and we just- we need to wait for further advances before we can really even know if it will pan out as a scientific theory.
M: Fair enough, yes, never say never in science, right?
S: Yeah
M: You can never say 'well, this is definitely the wrong way to go', because then the following week, some smart alec publishes a paper in Nature, and shows that you're wrong.
S: Right.
M: Correct, so that's a good point. But the point that Smolin is making, for instance in his book, I find it interesting, and it really deals more with the sociology of science, not as much with the philosophy of science. And the point is this: string theory has been so successful as an academic endeavour, that so many people are absolutely convinced that the theory is so beautiful that it really ought to be true – which incidentally is an interesting criterion, because it's an aesthetic criteria for science-
S: The argument from elegance
M: That's right, the argument from elegance, right? Which carries a lot of weight with physicists in particular, even though, actually, the history of science shows that a lot of beautiful physical theories have actually been disproved. But never mind that. The thing is, string theory has been so successful as an academic endeavour, that for many, many years, pretty much anybody who wanted to have a serious career in fundamental physics had to be a string theorist. Most of the positions, funded positions, were devoted to hiring string theorists, most of the grant money that was given by, for instance, the National Science Foundation, was going to string theory. So a fair question is to say 'well, yes, it may take you a hundred years, maybe it's a little too early to reach a conclusion, but how about we spread out our bets?'
S: Yeah
M: And fund other approaches, which-
B: Absoutely
S: Yeah, that seems perfectly reasonable. I think we should probably tell our listeners at this time who you are. Now, you've been on our show before, but for those who don't recall, you are actually a professor of philosophy, right? At City University of New York.
M: As of last year, yes
S: Yes, and you are the author of the 'Rationally Speaking' blog, I think you have other guest bloggers there too, but you're the primary one writing for that blog, and also one of the hosts with Julia Galef of the 'Rationally Speaking' podcast.
M: That's correct
S: Which is the official podcast of the New York City Skeptics
M: Yes, and we're having a lot of fun doing it, and pretty soon we're gonna have all of you as guests. One at a time.
S: (laughing) One at a time? Ok
R: Promises, promises
(laughter)
S: I've been listening to it, it's great, I think you're doing a good job
M: Thank you
S: Well let's go on to some other news items, we're gonna actually be coming back to this point on the demarcation problem a little bit later, when we talk about Sam Harris. But first, let's do some other news items
Definition of Siphon (11:11)
The Guardian: Dictionary definition of 'siphon' has been wrong for nearly a century
S: Did you guys hear that the Oxford English dictionary was wrong, had the wrong definition of the word 'siphon' in it for the last 100 years?
J: I'm outraged
S: Yeah?
E: Non-cromulent
B: How stupid are they?
R: Down with this sort of thing.
S: And-
J: Who dug down and found this one, Steve?
S: -and even worse, pretty much every dictionary consulted, copied, the Oxford English dictionary (OED), so this mistake was basically copied over and over again through most dictionaries. It was discovered by Dr Stephen Hughes, a physics lecturer at Queensland University of Technology in Brisbane. And- so, the term 'siphon' refers to the notion of siphoning off, or sucking a fluid from one body to another, just like draining some body of water by, you put a tube in there, you get the suction going, and then, once it starts going, it will continue to go. Now, the definition of how it works in the OED, and in most dictionaries, was that it was differences in air pressure, and if you hold the end of the tube below – the one that you want to drain to, below the end that's stuck in the body of water, the differences in pressure will push the fluid along and cause the drainage, which is simply not true.
R: Well, differences in 'atmospheric pressure'-
S: Yeah
R: But there is no difference in atmospheric pressure at such short distance, so it doesn't really make any sense. Actually, when I was in grade school, I learned how siphons worked, and I didn't realise the dictionaries had it incorrect, it's actually just due to gravity. Once you have the fluid going, if you have one end lower than the other, gravity, that's the force at work causing the fluid to flow through the tube, and then that creates suction, right? Cos if the water flowed down the tube and nothing came in to fill it, it would cause a partial, or total, vacuum in its wake. So gravity is the initiating force, and then-
B: Initiating?
S: Gravity's the force that moves the water down
B: Right
R: Sucking, is the initiating force
S: And then it's the resistance to the creation of a vacuum that then draws the water up to continue the process, right? So-
R: The reason why I mentioned- why I clarified atmospheric, that it's not atmospheric pressure, as that's what's in the dictionary, is because it is hydrostatic pressure.
B: Hydrostatic, right
S: Yes
R: So it is a kind of pressure, it's just not atmospheric
S: Yeah, not atmospheric, right, but the OED had atmospheric pressure as the explanation
B: Right, one guy had a great example, because a lot of people are still saying 'well, it's a combination of pressure and gravity, because you've gotta create some pressure differential to get it going, and then gravity takes over. One guys said, all you really need to do is put that tube in the water that's at a higher elevation, fill it with water, put a stopper in it, and then take that stopper, take the end with the stopper, bring it down to the lower container, remove the stopper, bam, you've got your siphon going with no sucking needed to get it started. So that's a great example of how you can get it going, showing that it's purely gravity, it seems-
S: Now, where atmospheric pressure comes in is when you're sucking something up against the gravitational gradient, right? So if you're drinking milk out of a straw, you suck at the high end of the straw that's in your mouth-
R: Well otherwise you'd be rather wet
S: You would be. That creates a vacuum, or partial vacuum, and there, what's pushing the milk up the straw is the atmospheric pressure pushing down on the surface of the milk, which is greater than the pressure inside the straw, because you've just created a partial vacuum. Now there are those who argue that the same thing is at work, the same principle is at work in getting the water to go up the segment of the siphon before it gets over the top, and then gravity pulls it down, and that is actually a legitimate point. So it seems, in reading about this, that there are a number of explanations for what the real driving force is on a siphon, and that can include – there is at least one contribution to – atmospheric pressure, although not the difference between the two ends of the tube, the difference in pressure inside the tube, that pressure gradient goes toward the lower end of the tube and that causes the water to flow. And that is contributed to by the atmospheric pressure on the surface of the water. Now, there are those that claim a siphon will work in a vacuum, although I was unable to find any empirical evidence of that, and several people pointed out that in a perfect vacuum, a liquid would evaporate really quickly, and therefore they're not sure how you could test that. But still there are others who say that the primary force is the tension between the water molecules, that you could treat water like a long piece of string, or a chain that's connected, so that when one end flows down, it pulls the other, it pulls the rest of the chain up, it's pulling the rest of the water up. So here's one way to resolve which of the two forces is more important: atmospheric pressure has a limit, it can only, you know, one atmosphere could only push water up a gravitational gradient about 10m, or 30 or so feet, 34 feet. It turns out that you can't siphon something greater than 10m up. If you have a reasonably sized tube, and you try to siphon, if the uphill component of that side, even if the other end goes below it, if the uphill component is greater than 10m, it won't work. Unless you have a really thin tube. If you have a really thin tube, you can get higher than 10m, because it's thin enough that the cohesion, the tensile strength between water molecules, is enough that, even when you're getting in to essentially negative pressures, you can get higher than what the force of atmospheric pressure can get to. So actually, I think in the final analysis, there's still a little bit of controversy about this, and there are contributions from both the atmospheric pressure and water tension with gravity being the driving force on the down-hill gradient, but what's drawing the water up is a combination of atmospheric pressure and water tension.
E: This is so much more easy to grasp than string theory.
(laughter)
M: So it appears, but don't you think that the real story here is that it took 100 years to figure this out? To find the error?
S: Exactly! I agree, this is kinda like a high-school science kind of mistake, or misconception, but the interesting thing is that it was not discovered for 100 years. Partly because everyone was content to copy the world's authority on the English language, the Oxford English dictionary and that-
B: Argument from authority
R: Yeah, and because everybody who knows what a siphon is, doesn't need to look it up in a dictionary. Everybody who doesn't know-
S&R: -doesn't know
J: Yeah, but how many times did eyes pass over that, right? How may people over the past 100 years had to read that and then re-publish it in another book? A lot of people looked at that, and it just got looked-over for 100 years.
R: And it's a dictionary too, not an encyclopedia, so the people who are editing it aren't scientists, they're editors, they're specialists in the English language
M: Right, but it's still interesting that this thing has been copied so many times. Because, yes, the Oxford, of course, is supposed to be an authoritative source, but that's the point, when you write something, like a new dictionary, you're not supposed to just trust somebody else's sources, no matter how good those sources are supposed to be. I don't think this is limited to dictionaries. I think a lot of stuff, for instance, I see a lot of textbooks in science that just copy freely examples and figures and tables from each other, and then it takes somebody to take a look at it and say 'oh no, wait a minute, that figure is wrong' and it turns out it's been wrong across many years, and across many different textbooks.
S: That's exactly right, in fact I remember reading an essay by Stephen Jay Gould in which he did a little investigation. He found that some majority of science textbooks were using the same very specific examples, which could really only be explained by just outright copying. For example, they compared the size of a hieroglypherium, the first horse, to that of a terrier, a dog. Why would that particular breed, there's no particular reason you would choose that breed as a comparison, but he found like 80% of the textbooks used that example, they must have just copied it forward, and copied it forward. So that's a real problem, it's just really laziness, you know?
Neanderthal Interbreeding (20:45)
CNN: Neanderthal genome shines light on human evolution
S: Let's go on, Bob, you're gonna tell us about Neanderthal DNA.
B: Yes I will. It now seems clear that, apparently, that modern humans, being the lascivious monkeys that we are, interbred with Neanderthals 50- or 60,000 years ago. Now, we know this not because of some ancient cave painting porn, but because most of us actually have Neanderthal genes in our very DNA.
S: Oh, I was hoping for the ancient cave-painting porn, myself
B: No, still looking for that.
R: I was looking forward to seeing that
(laughter)
B: For the record, "Neander-tal" and "Neander-thal" are both accepted pronunciations, so please don't send emails on that.
S: Yeah
B: So, this landmark scientific achievement, it was recently announced after a four-year effort by scientists at the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, and universities around the entire world. Now the fact that they could reconstitute 60% of the genome from people that were dead tens of thousands of years is amazing, if you wanna call them people, which I think is appropriate.
S: Sure
B: They did this by first grinding pieces of bone from three separate Neanderthal individuals, and then they had this bone dust, and then you kinda have to wade through all the modern DNA that contaminated it, just from handling, and all the bacterial DNA. I'm sure that that was in there as well, and just to find the Neanderthal DNA. So that was quite a tour de force just to get to that point. Fortunately, ancient DNA chemically degrades in a predictable way, and that allows this software that they've developed to detect it and correct for it. So that's how they were able to put all this together. They then compared this Neanderthal DNA to modern European, Asian, French and Papua New Guinean DNA, and finally they compared the DNA also, and more importantly, to western and southern Africa, individuals from western and southern Africa. And they found that 1-4% of the Neanderthal DNA was part of all this DNA, except the African DNA. So everyone that was European or Asian, or French or from Papua New Guinea, they all had a little bit of Neanderthal DNA, except the Africans. Now, the most likely interpretation of this data that makes sense, is that after modern humans left Africa, part of the 'out of Africa' hypothesis or theory, but before they could really separate and colonise the world, they interbred with Neanderthals, 60- to about 80,000 years ago, somewhere within there, probably in the mid-east, mixing in their DNA, which we can now see in probably billions of people. So that's basically the idea, you had an outflow of humans, of modern humans leaving Africa, but before they could essentially colonise the planet, they interbred with Neanderthals, which is why-
M: I bet it was mostly the French that did it.
(laughter)
E: Oh!
R: Alright
B: Fortunately, the French didn't even exist back then
(belch?)
B: Aw, man, that was good
R: Nicely done, Evan
S: I can't think of any other interpretation but that
B: Yeah, I can't either, it just seems like a natural conclusion
J: Bob, I have a question
B: Yeah
J: So that means that we're close enough to them genetically that we could breed with them?
S: Oh sure, I mean, that's not-
B: That's actually an interesting point. Some people, I'm sure, will say 'well, how could two species mate and produce fertile young?'. Well, actually, and this is interesting, the designation of Neanderthals has gone back and forth over the years. For decades, for the first 50 years after their discovery, or the first 50 years of the last century, most scientists considered them to be completely separate species, which is kind of a fuzzy concept anyway, but they call them Homo neanderthalensis. But lately, in the past few decades, scientists have been kinda thinking that they're more of a subspecies of Homo sapiens, and they call them Homo sapiens neanderthalensis, so my guess is that this latest research will solidify them as more of a subspecies to us, rather than a separate species.
S: Or, you know, it's more accurate to say that we're both subspecies, not that they are a subspecies of us.
B: Which is true, because they were around before we were, then maybe we should call ourselves Homo neanderthalensis sapiens, you know? Maybe we're a subspecies of them. And just the term subspecies, Steve, correct me if I'm wrong, that's more of a race, right? Kinda just like a race of humans.
S: Bob, it blends seamlessly one into the other
B: Right
S: It's all very, very fuzzy. The difference between a population, versus a race, versus a subspecies, versus a species is a continuum.
R: It might be closer to think of it as a breed, because of, like a dog breed. The difference between dog breeds is substantially more different than the difference between human races.
B: Yeah, I like that, but they're still the same species, yeah
M: It really depends on which definition a species one takes, there are several in biology, the one we've been implicitly referring to is the so-called biological species concept, which is this idea that if you interbreed, then you're part – and you can produce fertile offspring – then you're part of the same species. If not, you don't. But that concept of species is actually quite fuzzy, and it applies differently to different groups of organisms. To give you an extreme example, in a lot of plant species, and even in some vertebrates, there is quite a bit of inter-crossing between so-called species. Just think of orchids, for instance. So, just because things can interbreed, organisms can interbreed, that doesn't mean that they necessarily belong to the same species. As far as races versus populations, versus subspecies are concerned, that all depends really on who you ask, in terms of what view of systematic biology they take. Now, as far as humans are concerned, race is really an extremely fuzzy concept that has almost no biological grounding because there's been a lot of interbreeding within Homo sapiens, and so there is almost nothing that you can really say meaningfully about- from a biological perspective, not culture obviously, about- races are certainly no subspecies of humans at the moment, because a subspecies, as most of biology think of a subspecies as an incipient species, as a species that is about- as a population that is about to form a separate species. That may be what the Neanderthals were, you know, close enough to be a different species, but not quite.
S: (agreeing) mm-hmm
B: Right, good points
S: Yeah, even when you have two species that have clearly separated, they have separate populations that are different enough, either geographically or culturally, behaviourally, whatever, that they are mostly not interbreeding, and they're definitely on their way to becoming completely separated species. For a while, they will still occasionally exchange DNA. Remember a couple of years ago, there was the news item that analysis showed that human- about a million-
B: Yeah, chimps
S: -years after the split between humans and chimps, they were still swapping some DNA back and forth. So, I think that's the same situation-
R: How could I forget?
S: (laughing) with the same-
M: Because you're young, Rebecca
(laughing)
S: I mean, it always surprised me that Homo sapiens and Homo neanderthalscould live for tens of thousands of years in Europe together, and not be occasionally 'shacking up'. I mean, that is just human nature, if you will, and so makes more sense-
R: May be for you, pervert.
(laughter)
S: No comment
(laughter)
S: Let's go on to the next item-
B: Wait! Wait, something just occurred to me, something just occurred to me
J: Wait, let me pull the horse out so you can beat it to death a little further, ok, go ahead
B: No, no, this is interesting, they say 1-4% of the genome, but I assume that the similarities that they found were protein-encoding parts of the genome, right? It's not junk DNA they're talking about?
S: Who knows
M: Not necessarily, I think this is a genome-wide search
B: Yeah, but it's-
M: It may not be just protein coding
S: I don't know if that's relevant
B: Hmm, I don't know, the impression I- it is relevant, because if it's protein encoding, then it would be a much greater percentage of the protein-encoding part of the genome, as opposed to the entire genome-wide, you know what I mean?
S: It would be a higher percentage of our genes
B: Yes, that's my only point
S: Yeah
B: Yes, that's my only point
E: No, that's true, Bob
S: I don't know- yeah that's correct, but I don't know what the answer is
Evolution in Alabama Politics ( )
Politico.com: Alabama candidate denounces 'lie' that he believes in evolution
Science of Morality ( )
Huffington Post: Toward a Science of Morality
Who's That Noisy ( )
Answer to last week: Baba Ramdev
Science or Fiction ( )
Item #1: New research shows that while married men live longer than unmarried men, women do not gain this benefit from being married.
Item #2: The most extensive genetic analysis to date supports the conclusion that all life on earth descended from a single common ancestor.
Item #3: New observations indicate that much of the missing matter in the universe is not dark matter but rather a diffuse hot cloud of intergalactic gas made of normal (baryonic) matter.
Skeptical Quote of the Week ( )
Hegel was right when he said that we learn from history that man can never learn anything from history.
References
- ↑ Interiew with Michio Kaku – episode 182
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