Doomsday clock

It’s the 60th anniversary of the Bulletin of the Atomic Scientists, which premiered in December, 1945, just a few months after atomic bombs were dropped on Hiroshima and Nagasaki. The goal of the magazine has always been simple, if somewhat ambitious: to save the world by working to minimize the threat of nuclear war. It came out of a time when physicists were central players in questions of international security.

Doomsday ClockThe most famous product of the Bulletin is of course the Doomsday Clock, an iconic image that is far more famous than the magazine itself. The minute hand on the clock moves in response to the perceived danger of imminent global disaster. It’s fascinating to peek back at the timeline for the evolution of the clock, as it bounces back and forth in response to world events.

  • 1947: Seven minutes to midnight. Chosen mostly for artistic reasons, apparently. The original conception didn’t include the idea that the clock would actually move to reflect developments in international security.
  • 1949: Three minutes to midnight. The Soviet Union explodes its first atomic bomb.
  • 1953: Two minutes to midnight. The US and USSR explode hydrogen bombs.
  • 1960: Seven minutes to midnight. International cooperation to check the growth of nuclear weapons grows.
  • 1963: Twelve minutes to midnight. The US and USSR sign the Partial Test Ban Treaty, the first international arms-control agreement. (For some reason, the Cuban Missile Crisis doesn’t seem to have really registered — possibly it came and went too quickly.)
  • 1968: Seven minutes to midnight. France and China acquire nuclear weapons; arms stockpiles increase while development aid to developing nations languishes.
  • 1969: Ten minutes to midnight. The US Senate ratifies the Nuclear Non-Proliferation Treaty.
  • 1972: Twelve minutes to midnight. The US and USSR sign the first Strategic Arms Limitation Treaty (SALT I).
  • 1974: Nine minutes to midnight. Arms control talks stall; India develops a nuclear weapon.
  • 1980: Seven minutes to midnight. Small wars and terrorist activities grow, while arms-control talks remain stuck.
  • 1981: Four minutes to midnight. Terrorism and repression of human rights grows, along with conflicts in multiple theaters around the world.
  • 1984: Three minutes to midnight. Arms race picks up steam.
  • 1988: Six minutes to midnight. The US and USSR sign a treaty limiting intermediate-range nuclear weapons.
  • 1990: Ten minutes to midnight. Democracy flourishes in Eastern Europe; Cold War ends!
  • 1991: Seventeen minutes to midnight. The clock leaps dramatically backward as the Cold War remains over, and the US and USSR announce signficant cuts in nuclear stockpiles.
  • 1995: Fourteen minutes to midnight. Turns out that the peace dividend wasn’t quite what it might have been, as arms spending continues at Cold War levels. Fear grows of proliferation of nuclear weapons from poorly-controled facilities in the former Soviet Union.
  • 1998: Nine minutes to midnight. India and Pakistan go public with nuclear weapons.
  • 2002: Seven minutes to midnight. The U.S. rejects a series of arms control treaties and announces its withdrawal from the ABM treaty. Significant concerns about proliferation of nuclear weapons to terrorists.

So we’re right back where we started. If you don’t agree with the positioning of the clock as decided upon by the Bulletin’s board, you can always consult the Rapture Index for an alternative take on the imminence of Armageddon.

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Science reporting as it should be

As PZ and Chris Mooney point out, we finally see an article about evolution and creationism that gets it right — by making it clear from the outset that evolutionary theory is well-established science and supported by mountains of evidence.

When scientists announced last month they had determined the exact order of all 3 billion bits of genetic code that go into making a chimpanzee, it was no surprise that the sequence was more than 96 percent identical to the human genome. Charles Darwin had deduced more than a century ago that chimps were among humans’ closest cousins.

But decoding chimpanzees’ DNA allowed scientists to do more than just refine their estimates of how similar humans and chimps are. It let them put the very theory of evolution to some tough new tests.

If Darwin was right, for example, then scientists should be able to perform a neat trick. Using a mathematical formula that emerges from evolutionary theory, they should be able to predict the number of harmful mutations in chimpanzee DNA by knowing the number of mutations in a different species’ DNA and the two animals’ population sizes.

“That’s a very specific prediction,” said Eric Lander, a geneticist at the Broad Institute of MIT and Harvard in Cambridge, Mass., and a leader in the chimp project.

Sure enough, when Lander and his colleagues tallied the harmful mutations in the chimp genome, the number fit perfectly into the range that evolutionary theory had predicted.

Their analysis was just the latest of many in such disparate fields as genetics, biochemistry, geology and paleontology that in recent years have added new credence to the central tenet of evolutionary theory: That a smidgeon of cells 3.5 billion years ago could — through mechanisms no more extraordinary than random mutation and natural selection — give rise to the astonishing tapestry of biological diversity that today thrives on Earth.

Evolution’s repeated power to predict the unexpected goes a long way toward explaining why so many scientists and others are practically apoplectic over the recent decision by a Pennsylvania school board to treat evolution as an unproven hypothesis, on par with “alternative” explanations such as Intelligent Design (ID), the proposition that life as we know it could not have arisen without the helping hand of some mysterious intelligent force.

Kudos to Rick Weiss and David Brown of the Washington Post. And to everyone else: see, it’s not that hard!

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Life in the Solar System

Bitch Ph.D. is temporarily away, but loyal spouse Mr. B. has taken control and turned the site into — a science blog! Today he’s talking about the interesting issue of contaminating other planets with organisms from Earth.

Nowadays, when we send out space probes, we sterilize them. What little I know of this seems to indicate that our sterilization processes may be far from perfect. Regardless, the rationale for sterilization is sound — whether or not life exists or has existed at the probe’s destination, sending some of Earth’s life to the destination would potentially muck things up beyond repair. When we fear a spacecraft might not be sterile, we purposefully destroy it while it still has fuel enough to perform a fatal maneuver, as we did with the Galileo probe to protect the potential life on Jupiter’s moon Europa from earthy microbes possibly riding on the probe. These are real concerns that govern our use of current robotic space probes.

Suppose we didn’t worry about such things. Suppose there is life, an ecosystem, where we send a space probe. Suppose further, that some hardy bacteria or fungus stowed away on the space probe and is thereby introduced into the alien ecosystem. Chances are it will die out. However, there’s a slim chance that such stowaways could find habitat, potentially altering or even destroying an existing alien ecosystem.

I suspect it’s pretty unlikely that we will ever find anything worth of the name “life” on Mars or elsewhere in the Solar System, but I’m certainly no expert. If we did find anything, of course, it would be incredibly important, so I am happy to keep an open mind. (On the other hand, given the small chances, I agree with a colleague who says “It’s more important to look for supersymmetry than for life on Mars.”)

Still, one of the absolutely fascinating recent advances in the study of life’s origin has been the possible role of extraterrestrial chemistry. The classic Miller-Urey experiment demonstrated the possibility of creating amino acids by shooting sparks into a chamber designed to mimic the atmosphere of the young Earth. But apparently there’s good reason to believe that the Earth’s atmosphere wasn’t really like that in the experiment; in particular, it had more oxygen and less reducing compounds, and nobody has been able to make amino acids by zapping an atmosphere of that type.

On the other hand, conditions for synthesis of amino acids may exist in space! Interstellar clouds appear to be good places to create prebiotic organic compounds, or even proto-cells. It’s perfectly plausible that these could have been brought to Earth early on by crashing comets and meteorites. If so, it’s clear that the other planets would have received similar interplanetary donations of organic materials; no reason to believe that they necessarily evolved into life, but a fascinating possibility nevertheless.

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Bell curves

Back at the old blog we used to occasionally chat about the notorious speech by Harvard President Larry Summers, in which he suggested that intrinsic aptitude was a more important factor than discrimination or bias in explaining the dearth of women scientists. Examples here, here, here, here, here, and here. There was a lot of posturing and name-calling and oversimplification on either side of the debate, of course, which tended to obscure the basic fact that Summers was, as far the data goes, wildly wrong. Two favorite goalpost-moving maneuvers from his supporters were first to pretend that the argument was over the existence of innate differences, rather than whether they were more important than biases in explaining the present situation, and then to claim that Summers’ critics’ real motive was to prevent anyone from even talking about such differences, rather than simply trying to ensure that what was being said about them was correct rather than incorrect.

It was a touchstone moment, which will doubtless be returned to again and again to illustrate points about completely different issues. Here’s an example (thanks to Abby Vigneron for the pointer) from Andrew Sullivan:

DAILY KOS AND LARRY SUMMERS: It’s a small point but it helps illuminate some of the dumbness of the activist left. “Armando” of mega-blog/community board, Daily Kos, takes a dig at Larry Summers, and links to a new study on gender difference. I’m not getting into the new study here, but I will address Armando’s description of Larry Summers’ position. In a bid to be fair, Armando writes:

NOTE: Yeah I know Summers didn’t say men were smarter than women, he just said they had greater aptitude in math and the sciences than women. Huge difference.

This is one of those memes that, although demonstrably untrue, still survives. Read the transcript of Summers’ now infamous remarks. His point was not that men are better at math and the sciences than women, as Armando would have it. His point was that there is a difference not in the mean but in the standard deviation:

Even small differences in the standard deviation will translate into very large differences in the available pool substantially out. I did a very crude calculation, which I’m sure was wrong and certainly was unsubtle, twenty different ways. I looked at the Xie and Shauman paper – looked at the book, rather – looked at the evidence on the sex ratios in the top 5% of twelfth graders. If you look at those – they’re all over the map, depends on which test, whether it’s math, or science, and so forth – but 50% women, one woman for every two men, would be a high-end estimate from their estimates. From that, you can back out a difference in the implied standard deviations that works out to be about 20%. And from that, you can work out the difference out several standard deviations. If you do that calculation – and I have no reason to think that it couldn’t be refined in a hundred ways – you get five to one, at the high end. (My italics.)

Summers was addressing the discrete issue of why at the very high end of Ivy League math departments, there were too few women. His point, as the Harvard Crimson summarized it was that, in math and the sciences, “there are more men who are at the top and more men who are utter failures.” Armando is wrong; and he needs to correct the item. In fact, this is a good test of leftist blog credibility. Will he correct? I’ll keep you posted.

Ah yes, the good old standard-deviation argument. It’s the absolute favorite of those in the intrinsic-differences camp, since (1) it sounds kind of mathematical and impressive, and (2) they get to insist that it’s only the width of the distribution, not the mean, that is different between men and women, so really the argument doesn’t privilege men at all, while it manages to explain why they have made all the important contributions in human history. In a debate with Elizabeth Spelke at Edge, Steven Pinker rehearses the argument somewhat pedantically.bell curves
But let’s look at what the argument actually says, both explicitly and implicitly.

  1. Standardized tests scores reflect innate ability.
  2. Boys’ scores on certain tests have a larger standard deviation than girls’ scores, leading to a larger fraction of boys at the high end.
  3. The dearth of women scientists is explained by their smaller numbers on the high end of these tests.

Now, everyone who is familiar with the data knows that point 1 is somewhere between highly dubious and completely ridiculous; Summers himself admits as much, but it would ruin his story to dwell on it, so he soldiers on. But point 3 is interesting, and deserves to be looked at. It’s a nice part of the argument, because it’s testable. Is this difference in test scores really what explains the relative numbers of men and women in science?

Summers’ data comes from the book Women in Science: Career Processes and Outcomes by Yu Xie and Kimberlee Shauman. Interviewed shortly after his remarks, both Xie and Shauman were quick to criticize them, using words like “uninformed” and “simplistic.” We were fortunate enough to have Kim Shauman herself as a speaker at our Women in Science Symposium back in May. She pointed out that the studies Summers refers to can indeed be found in her book, right there in Chapter Two. But if you wanted to know whether the standard-deviation differences were actually what accounted for the dearth of women in science, you would have to read all the way to Chapter Three.

Here’s the point. By the time students are in twelfth grade, there is a substantial gap in the fraction of boys vs. girls who plan to study science in college. So it’s easy enough to ask: how much of that gap is explained by differing scores on standardized tests? Answer: none of it. Girls are much less likely than boys to plan on going into science, and Xie and Shauman find that the difference is independent of their scores on the standardized tests. In other words, even if we limit ourselves to only those students who have absolutely top-notch scores on these math/science tests, girls are much less likely than boys to be contemplating science as a career. Something is dissuading high-school girls from choosing to become scientists, and scores on standardized tests have nothing to do with it.

Now, looking at Sullivan’s post above, there’s nothing he says that is strictly incorrect. He is simply characterizing (accurately) what Summers said, not actually endorsing it. Still, he is certainly giving the wrong impression to his readers, by repeating a well-known allegation without mentioning that it is demonstrably false. It’s a small point, but it helps illustrate some of the disingenuity of the activist right. Sullivan is misleading, and he needs to correct the item. In fact, this is a good test of quasi-right-wing blog credibility. Will he correct? We’ll keep you posted.

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Lurker Day

Today is Lurker Day, as explained by Chris at Creek Running North, Lauren at Feministe, and PZ at Pharyngula. (Three of the coolest blogs on all the internets, I should add.) That is, lazy bloggers avoid posting original content by asking their readers who never (or rarely) comment to drop by and leave a note saying who they are and what they like about the blog. (Other blogs also ask for something called “constructive criticism,” or perhaps even for suggestions for improvement; we here at CV see no need for such things. But if you are so moved, knock yourselves out.)

I’m especially curious as to two demographic questions: how many readers are professionally science-related in some way vs. how many are from the so-called “real world,” and among the former, how many are students vs. embittered elders. No pressure, obviously; consider this just a chance to pipe up and say hi if you haven’t yet had the chance to comment.

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Pretty soon we're talking real money

The number being tossed about for post-Katrina reconstruction is $200 billion. That’s a lot of money, even for a cosmologist. If you spent a dollar per month throughout the entire existence of our observable universe, you’d only get up to about $164 billion.

How can we possibly pay for it? Mark Schmitt points to two ideas: a bad one and a good one. The bad one is a project being organized by Glenn Reynolds and N.Z. Bear to point the finger of shame at wasteful pork in the discretionary budget, in hopes that Congress will be moved to slice away this excess fat and free up funds for more important things. The germ of the idea is okay — wasteful pork is bad, why not trim it away — but the idea that they’ll reach $200 billion is fantasy-land. (At the moment they’ve reached about $14 billion, using an expansive definition of “pork” that includes, for example, all federal domestic-violence programs.) That’s because the part of the federal budget that they would even consider trimming is only about $500 billion. Schmitt quotes Stan Collender in the National Journal, who explains that “Social Security, interest on the debt, most other federal mandatory spending, the Pentagon, the costs of activities in Iraq and Afghanistan, homeland security and foreign aid” are off the table. The remaining $500 billion, by the way, includes all spending on science, education, and wasteful stuff like that. Rail against pork all you like, but it doesn’t make up 40% of the discretionary budget.

The good idea comes from the Center on Budget and Policy Priorities. They point out the obvious thing: the reason the government is having trouble paying its bills is because its revenues, as a fraction of GDP, are lower than they have been in decades. But even better, they home in on two tax cuts scheduled to kick in during 2006, which represent a particularly egregious example of benefiting the rich. One deals with personal exemptions, and the other sets the values of allowed itemized deductions, both applying to couples making over $218,950 or individuals making over $145,950.

who benefits from these tax cuts?

Some interesting features of these tax cuts:

  • President Bush didn’t even ask for them; they were inserted by Congress during the budget reconciliation process.
  • 54% of the money from these cuts will go to households earning over one million dollars per year, the wealthiest 0.2% of households.
  • 97% of the money from these cuts will go to households earning over $200,000 per year, the wealthiest 3.7% of households.
  • The total cost of the cuts, including interest on accrued debt, is $197 billion over ten years.

Hmmm.

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Theories, laws, facts

Could we just agree to tell the truth about this from now on? The New York Times has an interesting story by Cornelia Dean on the training that museums have started to give their docents and employees on how to deal with creationists. A sad commentary on our current state of affairs that such training is becoming necessary, but probably nobody reading this blog is surprised.

But as a supplement to the article, the Times reprints a FAQ from a pamphlet handed out by the Museum of the Earth in Ithaca, N.Y. It includes the following question:

Is evolution ‘just a theory’? A “theory” in science is a structure of related ideas that explains one or more natural phenomena and is supported by observations from the natural world; it is not something less than a “fact.” Theories actually occupy the highest, not the lowest, rank among scientific ideas. … Evolution is a “theory” in the same way that the idea that matter is made of atoms is a theory.

This is right in spirit, but the truth is not so very scary or technical that we can’t just fess up to it. The truth is that the hierarchy of “hypotheses” and “theories” and “laws” and “facts” that many people are taught in elementary school (or wherever) has absolutely no relationship to how real scientists use those words. Which is, that they are completely inconsistent and sloppy with their use. There is no procedure by which an ambitious young Hypothesis accumulates some promising support, and is brought up before the Most Supreme Council of Learned Scientists to be promoted to a Theory.

The reality of the situation is that it’s a mess. I can invent a half-baked idea tonight and call it a “model” or a “theory” and nobody cares, or would even notice. The Standard Model of Particle Physics is much closer to objective truth than Newton’s Law of Universal Gravitation, and the General Theory of Relativity is somewhere in between.

And “facts”? Eavesdrop on some scientists at work. You will go years without hearing any of them talk about “facts.” They’ll talk about data, and measurements, and observations, and experiments — those are things with identifiable meanings that we can work with. But call something a “fact” and you’re making some absolute metaphysical claim that isn’t the kind of thing scientists like to do. Likewise “proof.” Mathematicians and logicians, who deal with abstract symbols independent of any connection to nature, prove things. Scientists don’t. They figure out that certain beliefs should be held with greater and greater confidence, but proving something is simply outside the domain of science.

Which does bring us to the one almost-subtle point in this generally easy-to-understand business. Science never gets anything 100% right; it is always working on a better understanding, improving on the best current theory (or model, or whatever). But it does get some things right enough. The Big Bang, the round earth, Newton’s Laws, the Standard Model, natural selection — none of these is “proven” correct, but they are all correct, within certain domains of validity. There comes a point when, even though you can never (even in principle) prove an idea to be a fact, it becomes well-enough established that maintaining a skeptical attitude is a sign of crackpottery, not wisdom.

So let’s just quit the charade and let the unwashed masses in on the truth as far as “theory” is concerned. It’s a shorthand term for a model of some part of nature — but the label implies absolutely nothing about how true that model is. (The phlogiston theory didn’t stop being a theory once we knew it wasn’t true.) What matters isn’t whether we label something a “theory” or a “law” or a “fact,” it’s whether we label it “right” or “wrong.” As in, Darwin was “right,” the creationists are “wrong.”

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Lisa Randall on scientific communication

All I can say is, someone must be reading Cosmic Variance. Sunday’s New York Times has an Op-Ed piece by Lisa Randall on how scientists communicate with the public, and it echoes many of the issues we’ve been discussing here at CV. One of her themes is how words are used differently by specialists than they are in common usage.

Scientists’ different use of language becomes especially obvious (and amusing) to me when I hear scientific terms translated into another language. “La théorie des champs” and “la théorie des cordes” are the French versions of “field theory” and “string theory.” When I think of “un champs,” I think of cows grazing in a pasture, but when I think of “field theory” I have no such association. It is the theory I use that combines quantum mechanics and special relativity and describes objects existing throughout space that create and destroy particles. And string theory is not about strings that you tie around your finger that are made up of atoms; strings are the basic fundamental objects out of which everything is made. The words “string theory” give you a picture, but that picture can sometimes lead to misconceptions about the science.

These amusing images underscore a real issue: the unintentional confusion caused when a scientist is trying to be perfectly precise, yet creates an entirely incorrect impression in the mind of a listener. Words like “energy” or “work” or “uncertainty” can mean different things to experts and non-experts.

And the stakes are high:

The very different uses of the word “theory” provide a field day for advocates of “intelligent design.” By conflating a scientific theory with the colloquial use of the word, creationists instantly diminish the significance of science in general and evolution’s supporting scientific evidence in particular. Admittedly, the debate is complicated by the less precise nature of evolutionary theory and our inability to perform experiments to test the progression of a particular species. Moreover, evolution is by no means a complete theory. We have yet to learn how the initial conditions for evolution came about – why we have 23 pairs of chromosomes and at which level evolution operates are only two of the things we don’t understand. But such gaps should serve as incentives for questions and further scientific advances, not for abandoning the scientific enterprise.

This debate might be tamed if scientists clearly acknowledged both the successes and limitations of the current theory, so that the indisputable elements are clearly isolated. But skeptics have to acknowledge that the way to progress is by scientifically addressing the missing elements, not by ignoring evidence. The current controversy over what to teach is just embarrassing.

Word.

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Einstein vs. Physical Review

Despite the fact that the arxiv has made it possible to disseminate papers well before they are sent to a journal, the process of anonymous peer review is still crucial to physics and the rest of science. Anyone who has at least a couple of published papers has appeared on the radar screen of various journals as a potential referee, and pretty soon the requests to review papers come fast and furious. And it’s not a matter of rubber-stamping; I’ve personally refereed about 100 papers, and recommended less than half of them for publication. Of course, individual referees can behave quite differently; editors like referees who will actually read the paper, are willing to reject it if it’s bad, and get the reviews back quickly. I used to be good at all three of those, although my record on the last point has deteriorated seriously of late.

Every paper sent to a journal like Physical Review (in all of its contemporary manifestations) is sent to a referee as a matter of course. It wasn’t always thus. The current issue of Physics Today has a great article about Albert Einstein’s run-in with the journal in 1936.

Einstein In his salad days, Einstein published in German journals such as Annalen der Physik, but he eventually switched to American journals after he moved to the U.S. He had published a couple of papers in the Physical Review, which were apparently accepted by editor John Tate without being sent to a referee. These included the famous Einstein, Podolsky and Rosen paper on nonlocality in quantum mechanics, “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?

But in 1936 Einstein and Rosen submitted a paper on the existence of gravitational waves that struck Tate as suspicious, and he decided to send it to the referee. The Physics Today article reveals that the referee was relativist Howard Percy Robertson. Soon after the initial formulation of general relativity, Einstein predicted the existence of gravitational waves by doing the obvious thing — examining the behavior of small fluctuations in the gravitational field using perturbation theory. But Einstein and Rosen had attempted to solve the full equations without any approximations, and were able to prove that there were no non-singular solutions; they therefore claimed that gravitational waves didn’t exist! Robertson figured out that they had made a classic error in GR — essentially, they had used a bad coordinate system. He wrote a ten-page report explaining why the conclusions of the paper were incorrect.

Einstein explained that he had submitted his paper for publication, not for refereeing.

Dear Sir,

We (Mr. Rosen and I) had sent you our manuscript for publication and had not authorized you to show it to specialists before it is printed. I see no reason to address the — in any case erroneous — comments of your anonymous expert. On the basis of this incident I prefer to publish the paper elsewhere.

Respectfully,

P.S. Mr. Rosen, who has left for the Soviet Union, has authorized me to represent him in this matter.

After this incident, Einstein vowed never again to publish in Physical Review — and he didn’t. The Einstein-Rosen paper eventually appeared in the Journal of the Franklin Institute, but its conclusions were dramatically altered — the authors chose new coordinates, and showed that they had actually discovered a solution for cylindrical gravitational waves, now known as the “Einstein-Rosen metric.” It’s a little unclear how exactly Einstein changed his mind — whether it was of his own accord, through the influence of the referee’s report, or by talking to Robertson personally. But it’s pretty clear that he would have loved the innovation of arxiv.org.

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Love vs. Hate

Can’t say it much better than Jay Ackroyd at TPMCafe, so I’ll just quote in full:

All Hail Barney Frank

Last year, Barney said (I don’t have a link) that he was perfectly okay with the MA legislature passing an amendment banning gay marriage. He said that by the time the process was complete, (two consecutive legislative passages and a statewide vote) nothing bad would have come from anybody getting married. And so the amendment would die of its own weight.

NYTimes quotes lawmakers saying that he was right.

Like I’ve said all along, love and commitment will always, eventually, win out over bigotry and hate. It’s gratifying that it took so little time for the people of Massachusetts to realize that.

Congratulations to everyone in Massachusetts, this is a great step forward. Now if we could win approval for Plan B contraception, preserve the right to get an abortion, and convince everyone to leave the Catholic Church, we’d really have anti-sex conservatism on the run.

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