Tuesday, October 31, 2006
KZB will be at Congregation Beth Elohim, which to my knowledge holds the current record for hosting the largest number of independent minyanim (three: Kol Zimrah, Park Slope Minyan, and Altshul, never meeting at the same time). Kudos to CBE for their support of independent Jewish life. Kudos also to Kol Zimrah's Manhattan hosts, the Society for the Advancement of Judaism and the Jewish Home & Hospital.
This Friday is particularly exciting for me personally, because I have been to 57 out of 57 Kol Zimrah services, and after almost 4 years, number 58 is the first one I'm going to miss. When KZ is rocking the house in Brooklyn, I plan to be sound asleep in Haifa (where it's 7 hours later). It seems like ancient history now, but I can remember a time when Kol Zimrah depended on a few key people to keep it running. Since then, an amazing group of people has stepped up to provide leadership to KZ, and there are no indispensable individuals; leadership is distributed throughout the community. After this Friday, no one will have been to every single KZ service.
Saturday, October 28, 2006
I already voted for Hevesi before these violations made the news. (I guess they had already made the news a little bit, but I had missed the story, since this wasn't a race I was following carefully. Oops.) I can't say I would endorse him now, and I did note that comptroller is the rare type of office where party affiliation doesn't trump everything else in deciding whom to vote for. (I'm also not entirely convinced that the state comptroller should be popularly elected. At the federal level, we don't elect the Secretary of the Treasury. But I could be swayed either way.)
However, I want to point out to people who haven't voted yet that there are other options if you don't want to re-elect Hevesi but also can't bear to vote for a Republican for statewide office.
1) Vote for a third-party candidate, such as Julia Willebrand (Green) or Willie Cotton (Socialist Workers). Yes, this is probably an ineffective protest vote, but there's less at stake than usual.
2) Vote for Hevesi anyway (preferably on the Working Families Party line), taking the gamble that he'll resign or be removed from office before he begins his next term. Heck, this might even happen before Election Day. This way, his replacement will be selected by the state legislature, which has a Democratic majority, so it's the only way to make it likely that the next comptroller will be a Democrat. (It's not ideal -- it's too bad that this story didn't break in time for there to be a competitive primary.) (Note to FL-16 voters: do not pursue this strategy. Just look at the names on the ballot.)
Tuesday, October 24, 2006
--AZ-01: Rick Renzi
--AZ-05: J.D. Hayworth
--CA-04: John Doolittle
--CA-11: Richard Pombo
--CA-50: Brian Bilbray
--CO-04: Marilyn Musgrave
--CO-05: Doug Lamborn
--CO-07: Rick O'Donnell
--CT-04: Christopher Shays
--FL-13: Vernon Buchanan
--FL-16: Joe Negron
--FL-22: Clay Shaw
--ID-01: Bill Sali
--IL-06: Peter Roskam
--IL-10: Mark Kirk
--IL-14: Dennis Hastert
--IN-02: Chris Chocola
--IN-08: John Hostettler
--IA-01: Mike Whalen
--KS-02: Jim Ryun
--KY-03: Anne Northup
--KY-04: Geoff Davis
--MD-Sen: Michael Steele
--MN-01: Gil Gutknecht
--MN-06: Michele Bachmann
--MO-Sen: Jim Talent
--MT-Sen: Conrad Burns
--NV-03: Jon Porter
--NH-02: Charlie Bass
--NJ-07: Mike Ferguson
--NM-01: Heather Wilson
--NY-03: Peter King
--NY-20: John Sweeney
--NY-26: Tom Reynolds
--NY-29: Randy Kuhl
--NC-08: Robin Hayes
--NC-11: Charles Taylor
--OH-01: Steve Chabot
--OH-02: Jean Schmidt
--OH-15: Deborah Pryce
--OH-18: Joy Padgett
--PA-04: Melissa Hart
--PA-07: Curt Weldon
--PA-08: Mike Fitzpatrick
--PA-10: Don Sherwood
--RI-Sen: Lincoln Chafee
--TN-Sen: Bob Corker
--VA-Sen: George Allen
--VA-10: Frank Wolf
--WA-Sen: Mike McGavick
--WA-08: Dave Reichert
Sunday, October 22, 2006
Avi BenJakob from JewDot:
Instead of promoting lazy Jews with a hip new term, we should be celebrating Jews that truly embody what it means to be Jewish. BZ is a great example. He’s a self identified Reform Jew, but instead of saying I do whatever I want because I’m a Reform Jew, he has an ideology and every decision he makes is logically justified in that ideology. When there are more Jews like him across the spectrum we can finally stop worrying about Jewish Continuity and instead celebrate being Jewish.
Anyone want to suggest a hip new term for Jews that actually believe what they practice?
Reb Chaim HaQoton, posting a comment on Recovering Ortho Jew:
It's sad to see that someone as smart as Mah Rabu obviously is uses his mind to write and disseminate such garbage as what he proposed. And then the fact that he went around flaunting his grave sin on his blog.
Rachack, on the same comment thread:
Indeed it is ver ysad that someone would advertise something like that, but then again in a world were gays parade on the street showing of their homosexuality in public, what less can be expected?
I think this is going to be Karl Rove's October surprise. He'll turn out the base by running ads saying if you allow civil unions today, then tomorrow people will be shaking their lulavs on Shabbat!
Friday, October 20, 2006
Though I've lived in New York for over 4 years, I refuse to pick a New York team to root for. (In the major league, anyway. Go Brooklyn Cyclones!) So I was happy to see both New York teams get eliminated.
Now that we're approaching the World Series, I'm rooting against the Cardinals, due to the longstanding Cubs-Cardinals rivalry. It's a big deal in Chicago and St. Louis; I've been to Cubs-Cardinals games at Wrigley Field, and the ratio of Cubs to Cardinals apparel is around 60-40. Lots of people come up from St. Louis for the games.
Therefore, Mah Rabu endorses the Detroit Tigers to win the 2006 World Series.
However, the people of Missouri can have the stupid World Series championship if it somehow means that they'll elect Claire McCaskill to the Senate.
Hopefully, having two Midwestern teams in the World Series means that the coastally-based national media and/or liberal activists will be somewhat less obsessed with it, and people can focus on the election (cf. 2004).
But most of all, Mah Rabu is rooting for the World Series to be over so that we can have new Simpsons episodes again.
Thursday, October 19, 2006
Student 1: So if something was in space and there was no gravity, would it just keep going in a straight line forever?
BZ: For sure. This is from before your time, but does anyone remember Pioneer 10?
Student 2: [sarcastic] Oh yeah, I used to watch that show all the time.
Tuesday, October 17, 2006
(Also, I can't type "election" without first typing "electron" by mistake. It's an occupational hazard.)
Here is the list of candidates for NYC. Apparently the Rent Is Too Damn High Party has been bowdlerized to Rent Is Too High. See their website for more details.
I plan to vote for:
- Governor / Lieutenant Governor: Eliot Spitzer / David A Paterson (Working Families)
- State Comptroller: Alan G Hevesi (Working Families)
- Attorney General: Andrew M Cuomo (Working Families)
- United States Senator: Hillary Rodham Clinton (Working Families)
- Representative in Congress (15th District): Charles B Rangel (Working Families)
- State Senate (31st District): Eric Schneiderman (Working Families)
- Member of the Assembly (67th District): Linda B Rosenthal (Working Families)
This is not democracy. And maybe democratic elections aren't the best way to pick judges anyway; maybe it would make sense to have them appointed and confirmed as they are in the federal judiciary. But the status quo is much worse, because it creates the illusion of democracy without any of the substance. Judicial candidates are chosen by party bosses, with no accountability to the voters. (If judges were appointed, they would at least be chosen by elected officials.)
I refuse to participate in this sham, so I plan to cast a write-in vote in protest. Any suggestions on whom I should write in? Desh may have inspired me to write in my own name, but I don't think I'm qualified for the position of judge (though perhaps more qualified than these guys).
Monday, October 16, 2006
DEMOCRATS FOR EVERYTHING
That is all.
The merits of the individual candidates don't matter one whit. There's a time when the voters can and should have input on the individual candidates. IT'S CALLED THE PRIMARY. (And I support making primaries more competitive, though maybe I'm saying that from a position of privilege, living in a one-party state.) In the general election, the only thing that matters is which party will hold a majority in each house of Congress. Everything else is insignificant in comparison.
I probably don't need to preach to the choir and argue for why we need to boot out the party that lied to the American people and the world so that we could enter a war that has killed over 2700 US soldiers and 600,000 Iraqis and cost over $300 billion and turned the formerly stable albeit authoritarian Iraq into a flaming cesspool of chaos that is now the breeding ground for terrorism that it never was before and made this country and the world immeasurably less safe and steadfastly refuses any congressional oversight into the administration's disastrous policies and called an emergency session to intervene into the private medical affairs of a terminally ill woman but left hundreds of thousands to suffer and die in New Orleans in order to further their criminally negligent conservative philosophy and voted to abrogate the centuries-old right of habeas corpus and voted to hand billions of tax dollars back to the extremely wealthy while impoverishing the federal government and the rest of the American people and supports a government that is bought and paid for by corporate lobbies and provides shelter to child predators while preaching "family values".
The Republicans have got to go.
And the Democrats are the only alternative.
Are the Democrats perfect? No. (Though they are better than the Republicans on every issue.) Is the two-party system perfect? Of course not. But we can't get rid of the two-party system by putting our fingers in our ears and pretending it doesn't exist. Let's first get the Republicans out of power, and then we can clean our own house.
If you think the voting records or positions of individual members of Congress mean anything whatsoever, then you're living in a pre-1994 fantasyland. Starting with Gingrich and continuing with Hastert/DeLay/Frist, Congress has moved toward a parliamentary system where the party leadership reigns supreme. We can argue (preferably in our spare time after November 7) about whether this is beneficial, but we can't deny that it's the way things are.
The party that controls Congress gets a majority on all the committees, and therefore gets to decide which legislation does and doesn't make it to the floor. Once a bill is on the floor, any "debates" are a sham, just posturing for the C-SPAN cameras. After a bill has been assured passage, individual Congresspeople in both the majority and the minority can decide to break with their parties to appear "moderate" for the voters back home. However, they're not really taking a principled stand, since these stands only happen when it won't affect the outcome of the vote.
So it doesn't matter, for good or for ill, whether an individual senator/representative has positions outside the mainstream of his/her party. Yes, Bob Casey (D-PA) is pro-coathanger-abortions, like his Republican opponent Rick Santorum. And yes, Lincoln Chafee (R-RI) is pro-choice, like his Democratic opponent Sheldon Whitehouse. But THAT DOESN'T MATTER. Even if the only issue you care about is reproductive choice, you should still support a pro-coathanger-abortion Democrat over a pro-choice Republican. If Casey is elected to the Senate, along with enough Democrats to take over the majority, then no bill restricting reproductive rights will ever make it out of committee. If Chafee is elected and the Republicans retain their majority, then there will be a speedy confirmation for the next Roberts/Alito-style Supreme Court nominee who tips the court towards overturning Roe v. Wade, even if Chafee himself gets to vote valiantly against the nominee and Cheney has to break a tie.
As Krugman said today, "The fact is that this is a one-letter election. D or R, that’s all that matters."
(Though if you support a Republican majority, then you probably shouldn't listen to raving lefties like me or Krugman! Don't worry about party affiliation - look at the individual candidates and vote your conscience!)
When the Democrats take over Congress, Speaker-to-be Nancy Pelosi has already stated the party's goals for the first 100 hours:
Day One: Put new rules in place to "break the link between lobbyists and legislation."
Day Two: Enact all the recommendations made by the commission that investigated the terrorist attacks of Sept. 11, 2001.
Time remaining until 100 hours: Raise the minimum wage to $7.25 an hour, maybe in one step. Cut the interest rate on student loans in half. Allow the government to negotiate directly with the pharmaceutical companies for lower drug prices for Medicare patients.
Broaden the types of stem cell research allowed with federal funds _ "I hope with a veto-proof majority," she added in an Associated Press interview Thursday.
And it continues from there.
As important as it is to take over Congress, the importance of electing Democrats (prioritizing party affiliation over individual merits) goes beyond Congress. The Republican domination of the House of Representatives has been assisted by gerrymandering by Republican state legislatures, most notably in Texas, but around the country as well. With the Supreme Court upholding the constitutionality of mid-decade redistricting, it is essential that Democrats control as many state legislatures as possible, so that the Democratic party is drawing the congressional lines.
Of course, Democratic majorities in state governments are important beyond redistricting. Chris Bowers of MyDD writes:
It is in the states where we build our benches for higher office, and our benches had been severely depleted since 1994. It is in the states where progressive legislation will first appear before it is adopted nationally, and even a Democratic Congress in D.C. won't be able to adopt much progressive legislation as long as bush is President. It is also in the states where voters maintain their core partisan identification, and where GOTV operations preside. It is also in the states where the control over much election machinery and congressional maps is held. Controlling the states is the backbone to any national governing coalition. In 2006, Democrats look set to take clear control of the states for the first time since 1994. As much as anything else, that will stop the conservative movement in its tracks, and help change the direction of this country.
As we saw in Florida in 2000 and then Ohio in 2004, partisan affiliation can matter even for seemingly nonpartisan offices like state Secretary of State. Therefore, the Secretary of State Project is working to elect Secretaries of State who will ensure fair elections and protect voter rights.
So the only offices for which I endorse giving even one thought to the individual candidates in the general election (rather than the letter after their name) are the less "political" state offices (like Comptroller), and local offices (such as mayor and city council, or the equivalent in your municipality) where the national parties may have less influence. I still don't think I could bring myself to vote for a Republican for any of these offices, but would seriously consider an independent or third-party candidate.
Otherwise, to reiterate, Mah Rabu's endorsement is
DEMOCRATS FOR EVERYTHING
There are two exceptions where I would endorse voting for someone without a "D" after his/her name, but both of these exceptions still work towards the goal of Democratic majorities in Congress.
1) If you live in Vermont, vote for Bernie Sanders (I) for Senate. Rep. Sanders is an independent candidate and self-described socialist, but has been endorsed by the Democratic party, and there is no Democratic candidate in the race. He will continue to caucus loyally with the Democrats.
2) If you live in New York, vote for the Working Families Party for the races in which they've endorsed the Democratic candidate. New York has electoral fusion laws, so a candidate can run on multiple ballot lines, and his/her votes on all lines will be added together. So a vote for the WFP is a way to send a message without doing anything destructive. As the WFP says on their website, "Eliot Spitzer knows that every vote he gets on Row E - the Working Families Party ballot line - is a vote for progressive change to solve problems with our schools, health care, housing and jobs." The WFP has explicitly expressed support for taking back a Democratic majority in Congress.
The Connecticut Senate race is not an exception. Joe Lieberman (Connecticut for Lieberman) has abandoned all ties to the Democratic party, and is drawing most of his support from Republicans. Though he made a name for himself attacking Clinton on "family values", he has defended Hastert from accountability in the Foley scandal. Most recently, he said "Uh, I haven't thought about that enough to give an answer" when asked whether he wanted the Democrats to take back the House.
It is a very real possibility that the Senate will end up 49-49-2 (with Sanders and Lieberman as the two independents). If this happens, given Lieberman's conduct toward the Democratic party, why wouldn't Lieberman decide caucus with the Republicans and hand the tiebreaker to Dick Cheney, or use this as a threat to extort concessions from the Democrats? Bowers discusses what this would mean.
If you're in Connecticut, vote for Ned Lamont, a real Democrat. (Or if you're a Republican and can't bring yourself to vote D, then vote for your party's nominee, Alan Schlesinger, because, um, Lieberman might caucus with the Democrats.)
VOTE OR DIE
So we've had fun looking at the properties of jerk. Yes, that's really the accepted term for the derivative of acceleration (the third derivative of position). There are as yet no official terms for higher derivatives, but snap, crackle, and pop have been proposed for the 4th, 5th, and 6th derivatives of position. I wouldn't be surprised if these names get canonized one day; as whimsical as they are, they're no less serious than up, down, charm, strange, top, and bottom.
I explained why jerk was called jerk. If you're moving at constant velocity, it doesn't feel like anything, since there's an inertial frame of reference in which you're not moving at all. If you're moving with constant acceleration, it feels like you're experiencing a constant force, which feels just like a gravitational field, thanks to the equivalence principle. If you're moving with non-constant acceleration, then you experience a non-constant force. Since this "force" is changing, you feel jerked around.
One student asked "What would snap feel like?" I didn't have a great answer, so I said "One second there's no jerk, and then the next second there is. That's snap!" Another student said "So if you want to call someone a jerk, then when they walk into the room, you can say 'Oh snap!'" My children have defeated me.
I gave a practice problem where acceleration was given as a function of time, and included a term proportional to the square root of time. They had to find the velocity, position, etc. A student astutely pointed out that this means that the jerk is undefined at t=0. Readers, you can correct me if I'm wrong, but I said that's totally legal, and here was an intrusion of actual physics into our otherwise purely mathematical world of kinematics. Newton's Second Law says F=ma, so the acceleration must exist and be finite at each point in time. Acceleration can't be infinite, because this would require an infinite force, and that's impossible. (You might say that an inverse-square force is infinite when r=0, but I would respond that classical electromagnetism doesn't really allow point charges, but only finite-density charge distributions. This probably means we should be a little bit more careful about using point charges in all our examples, but they're useful approximations if we don't think too hard about it. But point charges can't exist because they would result in infinite electric fields, which results in infinite energy density, and if you integrate the energy over any finite volume containing a point charge, you get infinite energy. If you were to define the energy density of the gravitational field, I think you would get a similar result showing that point masses are impossible.) Therefore, velocity must be continuous. However, there's no reason that acceleration needs to be continuous (and thus no reason that jerk always needs to be defined), since it's theoretically possible to have a force that's there one instant and gone the next.
This gets into an argument that I used to have with a former colleague, MF. He would claim that Newton's Third Law is the only one of Newton's laws that contains any actual physics. (I like teaching my students "Newton's Zeroth Law", an example of how physics education research can provide insights not only about physics education, but about physics. But that's not really one of Newton's laws.) Of course, Newton's First Law doesn't tell us anything that we couldn't easily deduce from the Second Law by setting force to zero, assuming nonzero mass, and solving for acceleration. It's worth teaching anyway, not only for historical reasons, but because this specific case is contrary to the intuitive understanding of how forces work (just ask Aristotle), and it provides a useful way of thinking about forces in equilibrium. But in a pinch, we could get by without the First Law. (Similarly, the chemistry teachers in my office complain about having to teach Boyle's, Charles's, and Gay-Lussac's Laws when they can all be subsumed under the Ideal Gas Law, so the students have to learn 4 laws (again, perhaps primarily for historical reasons) when one would suffice. Giving the other three laws their own names might help in keeping track of the various direct and inverse relationships, but in this case, the extra laws might just be more confusing. I don't know, not my field. Except when the freshmen say they want to take the Physics SAT II.)
So really, the dispute is about the Second Law. Does it say anything meaningful about physics, or is it just a definition of force?
MF follows Feynman, who says (Feynman Lectures, volume I, chapter 12):
If we have discovered a fundamental law, which asserts that the force is equal to the mass times the acceleration, and then define the force to be the mass times the acceleration, we have found out nothing. We could also define force to mean that a moving object with no force acting on it continues to move with constant velocity in a straight line. If we then observe an object not moving in a straight line with a constant velocity, we might say that there is a force on it. Now such things certainly cannot be the content of physics, because they are definitions going in a circle. The Newtonian statement above, however, seems to be a most precise definition of force, and one that appeals to the mathematician; nevertheless, it is completely useless, because no prediction whatsoever can be made from a definition.
However, I would respond by also quoting Feynman (the very next paragraph):
For example, if we were to choose to say that an object left to itself keeps its position and does not move, then when we see something drifting, we could say that must be due to a "gorce" -- a gorce is the rate of change of position. Now we have a wonderful new law, everything stands still except when a gorce is acting. You see, that would be analogous to the above definition of force, and it would contain no information. The real content of Newton's laws is this: that the force is supposed to have some independent properties, in addition to the law F = ma; but the specific independent properties that the force has were not completely described by Newton or by anybody else, and therefore the physical law F = ma is an incomplete law. It implies that if we study the mass times the acceleration and call the product the force, i.e., if we study the characteristics of force as a program of interest, then we shall find that forces have some simplicity; the law is a good program for analyzing nature, it is a suggestion that the forces will be simple.
For example, in dealing with force the tacit assumption is always made that the force is equal to zero unless some physical body is present, that if we find a force that is not equal to zero we also find something in the neighborhood that is a source of the force. This assumption is entirely different from the case of the "gorce" that we introduced above. One of the most important characteristics of force is that it has a material origin, and this is not just a definition.
A more concise version of this (from chapter 9):
In order to use Newton's laws, we have to have some formula for the force; these laws say pay attention to the forces. If an object is accelerating, some agency is at work; find it.
As we currently understand it, the universe has four fundamental interactions. We'll ignore the weak and the strong interactions in this post, because we're talking about classical physics, and they don't operate on large enough scales to be adequately described by classical physics. That leaves the gravitational and electromagnetic interactions, and as far as we are aware, they are forces; i.e. they cause objects to have acceleration: the second derivative of position, not the first, third, fourth, etc. So Newton's Second Law is actually making a physical statement about our universe, since it says that the fundamental interactions of our universe (which are not themselves fully described by Newton's Laws, even in the classical approximation) cause acceleration.
We could imagine alternate universes where these fundamental interactions cause velocity, jerk, snap, or something else entirely (e.g. a universe where the components of motion are not independent, so force cannot be described by a vector quantity).
Therefore, I gave the AP class this extra credit question on their most recent test. Some of them even got it right! Bonus points to the first Mah Rabu reader who can solve it. Post your answers in the comments.
Consider an alternate universe where
’s Second Law is F = mj. In our universe, all objects in free fall in a uniform gravitational field have a constant acceleration. In this other universe, they would have a constant jerk instead! In our universe, a projectile thrown from a level surface at a given initial speed would have the greatest horizontal displacement if it is thrown at an angle of 45° from the horizontal. What is the corresponding angle in this alternate universe? (You can assume that the projectile has no initial acceleration.) Newton
Sunday, October 15, 2006
Outside BJ, on the sidewalk across the street, was a klezmer band, with an entourage wearing 1920s-style (I think) clothing, holding a sign saying "We are the Sukkos Mob". Some of the overflow people from BJ were dancing to the music. Does anyone know who they are? There's only one Google hit for "Sukkos Mob" -- they're listed as part of the DUMBO Art Under the Bridge Festival, which apparently was this weekend, except that the Upper West Side is not so close to DUMBO.
Inside BJ, S"Y and others were beatboxing into the mike during the dancing, and then freestyling later on (after the official proceedings had ended), so we were treated to the hiphop remix of "Ki miTziyon".
Otherwise I did the usual, doing yom tov stuff on yom tov, and then celebrating afterwards with the Torah even though it wasn't yom tov. Really, if the community wants to get together and celebrate Torah ("chavurat tzedek eidah zo ha-me'usharah, zekeinim un'arim yachad bechol shurah, kevutzim poh hayom lesimchat torah"), even though it's not yom tov, who am I to argue? They're not hurting anyone. As someone said last night, this was one rocking melaveh malkah. And there is precedent for having a big party after the conclusion of yom tov.
Since today was Sunday, I didn't have to work, so I heard the end and beginning of the Torah at the dar. Just for fun, at one of the many Torah reading stations, we revived an ancient practice and did two aliyot with line-by-line translation into Aramaic! It would have been a whole round of Vezot Haberachah (or should I say, Veda Virketa), but we quickly realized that Onkelos was too verbose. The problem is that no one understands what Vezot Haberachah is talking about, so Onkelos wasn't merely translating, but taking twice as many words to explain what (he thought) it meant.
Question for the armchair posekim of the blogosphere: Everyone who wanted an aliyah this morning got one. Since I (very openly) observe one day of yom tov, would it have been appropriate for me to take one? Why or why not? To keep you unbiased, I won't say what I actually did.
מקראי קדש אשר תקראו אתם -- יכול כל יום שרוצה ישראל לקרא מקרא קדש יקרא תלמוד לומר במועדם
Friday, October 13, 2006
Monday, October 09, 2006
Sunday, October 08, 2006
Wednesday, October 04, 2006
This post addresses a rarely-explored consequence.
Leviticus 23:40 commands only that the four species be taken on the first day, and says nothing about what should be done the other days of the holiday. Therefore, the Mishnah (Sukkah 3:12) says that outside of the Temple, the lulav (synecdoche for all four species) was taken only on the first day, and it was taken all 7 days in the Temple. (Sifra Emor 16:9 (I think? I don't know the proper citation format) derives this from the end of the same verse, where it says "you shall rejoice before God 7 days", suggesting that lulav should be taken 7 days when you're "before God", i.e. in the Temple. Thanks, EAR, for the Bar-Ilan login.)
According to the same mishnah, when the Temple was destroyed, Rabban Yochanan ben Zakkai decreed that the lulav should be taken all 7 days everywhere, in remembrance of the Temple. For those keeping track, lulav on the first day is still a Torah commandment, while lulav on the other 6 days (outside the Temple) is a rabbinic decree.
Later on, the Mishnah (Sukkah 4:1) says that the lulav is "6 and 7". That is, as elucidated in Sukkah 4:2, if the 1st day of Sukkot falls on Shabbat, the lulav is taken all 7 days, and if it falls on any other day of the week, the lulav is taken 6 days (every day except Shabbat).
Why? Rabbah explains in the Gemara (Sukkah 42b) that this is a decree to prevent people from carrying a lulav in the public domain on Shabbat, the same decree that applies to shofar and megillah. I don't quite see the point of this -- the Mishnah (Sukkah 3:13 and 4:3) already discusses solutions for benching lulav on Shabbat (in this case, when yom tov falls on Shabbat) without carrying on Shabbat, viz. everyone brought their lulavs to the synagogue/Temple before Shabbat, and when that got too ugly, they started benching lulav at home instead. I don't see why that couldn't work just as well for Shabbat Chol Hamo'ed. But even if I don't agree with Rabbah's reasons, I don't have a problem with this decree -- chaza"l gives and chaza"l takes away. The rabbis are the ones who established the practice of lulav on days 2-7 of Sukkot in the first place, so they get to impose constraints on it. But they don't impose any constraints on lulav on day 1 (at least the Mishnah and the earlier amoraim like Rabbah don't), because it's a Torah commandment that they can't overrule.
So, you ask (as does the Gemara, on Sukkah 43a), how do we get from there to the present-day practice that lulav is not done on Shabbat even when it's the 1st day of Sukkot? The Gemara answers that "we" (here in Bavel) don't know the correct date of the new moon in time for the holiday. So for the same reason that they observe 2 days of yom tov (because they don't know which one is the real 15th of Tishrei), the Torah commandment to take the lulav on the 1st day of Sukkot can't override Shabbat if this epistemological uncertainty means that they're not sure it's really the 1st day of Sukkot, so they might be breaking (an electrified fence around) Shabbat for nothing.
But wait a second, you ask (as does the Gemara), what about in Israel, where they observe 1 day of yom tov, since they're certain about which day is the real 15 Tishrei? Shouldn't they bench lulav on Shabbat when it's the 1st day of Sukkot, since it's definitely the 1st day of Sukkot, so the Torah commandment should win? The Gemara responds "In hachi nami." ("Yeah, you're right.") Oops.
To this day, in Israel, the most common practice is not to bench lulav on Shabbat, even when it's the 1st day of Sukkot. The Gemara provides evidence that this has been done for at least 1500 years, but was known to be erroneous 1500 years ago.
In I Samuel 8, the people ask Samuel to give them a king, and he gives them a list of reasons why this would be a bad thing, and they say that they want a king anyway. During the English Revolution, this chapter was used as a prooftext both by supporters and opponents of monarchy. There are two different possible responses to "They knew this was wrong, and did it anyway": 1) "See, they knew it was wrong!" 2) "See, they did it anyway!"
In this case (lulav for 1-day-yom-tov observers when the 1st day of Sukkot falls on Shabbat), I'm going with approach #1 and holding by the Talmud when it calls the practices of its own time mistaken, though there are also cases when I go with approach #2 (see: kitniyot). Therefore, I will bench lulav this Shabbat, as will the minyan that I am visiting (I presume for similar reasons).
In fairness to the other side, I'll present some later views. The Rambam (Hilchot Lulav 7:17) codifies the practice that the Gemara calls erroneous, but (unlike the Tur / Beit Yosef / Shulchan Aruch) gives a reason: so that everyone is equal, and the Israelis (1-day observers) and the Diaspora residents (2-day observers) aren't keeping two separate practices.
To that I respond, his desire for unity is all well and good, but it's way too late for that -- if the Diaspora is already keeping A WHOLE EXTRA DAY OF YOM TOV, then what's a lulav here and there? Also, if we're going to have everyone do the same thing, wouldn't it make more sense to have everyone bench lulav (and fulfill the Torah commandment) than to have everyone not bench lulav (and fulfill the rabbinic decree)?
In Hilchot Lulav 7:18, he says that this practice of not benching lulav on Shabbat, even on the 1st day, in both 1-day and 2-day communities, stands in the present time when we determine the calendar by calculation rather than by eyewitness testimony. But he provides no further explanation.
Chag sameach! May your holiday be nothing but happy.
UPDATE: See the comments. On the following daf (Sukkah 43b), the Gemara indeed says that Eretz Yisrael should follow the Diaspora and not shake the lulav on Shabbat. Does that invalidate this whole post? Not necessarily. See the discussion in the comments for more.
1. One thing I like about Yom Kippur is that there is almost no time between waking up and leaving the apartment. On all other mornings I do things like check email, brush my teeth, shower, eat breakfast, check email again, and put on shoes. On Yom Kippur I do none of these things, so there is a sense of transcending the physical world for a day. Along these lines I enjoyed abunaftali's Traditional Yom Kippur Stew, and kept up Bluegrass Pirate's minhag of placing two books on the table under a challah cover as the day's sustenance.
2. I led mincha at the dar, my first time leading YK services. Right before it started, I didn't know how I was physically going to make it through, since my mouth was dry after 23 hours of fasting. It turns out that adrenaline is an amazing thing. The fight-or-flight response did its job. The hardest part (physically) was standing straight with my feet together for the whole repetition (around 40 minutes), as my fast approached 24 hours. I held out, but had difficulty standing through ne'ilah (which I wasn't leading). I have no idea how anyone can lead musaf, which requires standing in one place for 3 hours. How does this work? I suppose the prostration can break things up.
3. This is less amusing as last year's thoughts on the liturgy, but about as significant. The second line of David Broza's song "Yihyeh Tov" is "Ha'aviv chalaf avar lo, mi yodeia im yashuv?" ("The spring has gone away; who knows if it will return?") I always knew that the first half of the line was a through-the-looking-glass reference to Song of Songs 2:11, but just realized this year during the haftarah that the second half was a reference to Jonah 3:9. Who knew that this song was so erudite?