I think that this is a good thing, for the same reason that Ramesh (presumably?) thinks it bad–because if true, it provides constitutional protection for cloning.

Twenty years ago, a political science professor at the University of Michigan came out with a seminal book titled the Evolution of Cooperation.

In it, he described how cooperative strategies could have evolutionary-beneficial consequences, and thus be selected for. In particular, via a series of computer game tournaments in which algorithms were submitted to play an extended iterated prisoner’s dilemma, he identified a strategy that was the most successful called “Tit for Tat” (TFT). (Read the link for information as to how the game works.)

In this strategy, you retain a memory of past interactions with other entities, and you treat them exactly as they treated you the last time you dealt with them. If they cooperated the last time, you cooperate. If they defected on you the last time, you defect on them the next. If it’s your first interaction, you cooperate.

The strategy has four characteristics that made it successful. It’s simple and can be clearly and easily recognized after a brief period of time, it’s forgiving, it’s provocable and retributive (so that you can’t get away with screwing it), and it’s nice (that is, it never screws anyone for no reason–its default is to cooperate). In essence, it is cooperative, and is rewarded for being that way.

One of the interesting things about it is that the more similar algorithms it has to deal with, the better it does. Put in an environment of non-cooperators, it has a much harder time, but it can still be more successful than them, and if it has a few others to cooperate with, it can survive even in a sea of non-cooperators.

Non-cooperators, on the other hand, don’t do well in a cooperative society. A non-nice strategy (one that always, or occasionally, or randomly defects unprovoked) won’t do well in a world of TFTs, because after the first time they get screwed by it, they will not cooperate with it again, at least until it changes its ways. So while it gets a big payoff the first time, it gets a much smaller one in subsequent exhanges, whereas the TFTs interacting with each other always get the medium benefit.

Thus, it’s possible for a small group of cooperators to “colonize” a larger group of non-cooperators, and eventually take it over, whereas a group of non-cooperators invading a larger group of cooperators will not thrive, and will eventually die out. This is the basis for Axelrod’s (and others’) claim that there is evolutionary pressure for cooperation to evolve.

This may hold the key to fixing Iraq, and ultimately the Middle East. While there’s a lot of bad news coming from that country right now, the fact remains that much of it is calm and at peace–that part doesn’t make the news. It may be that nationwide elections won’t be possible in January, but certainly it should be for some regions (particularly the Kurdish region).

The Jihadists and ex-Ba’athists are determined to prevent a democracy from forming there, but if such can be established in large areas, it will provide an unnurturing environment for them there. Then we can gradually expand them, and tighten the noose around the Fallujahs over time. What we have to pay attention to is not the level of violence, but over how widespread a region it is. As more and more of the country becomes not only pacified, but wealthier, with a stake in continued peace and freedom, we can continue to shrink the territory in which the terrorists, the ultimate non-cooperators, can survive, and eventually kill them or starve them out.

For my move to Florida, if this article is correct.

Scientists say we are in a period of enhanced hurricane activity that could last for decades, ending a 24-year period of below average activity. They also say the law of averages has caught up with Florida, with a change in atmospheric steering currents turning the state into a hurricane magnet.

Great.

Ivan probably won’t be the last storm to have us in its boresight this year.

It makes me start to wonder how big, or how many nukes it would take to disrupt these damned things, or if that’s even feasible (ignoring, of course, the radiation issues)?

[Update a minute or so later]

As if they didn’t have enough to deal with, with a Category 5 hurricane bearing down on them, the Caymans and Jamaica just had a Richter 6 earthquake.

I, of course, blame George Bush.

ESA (the European one, not the Elbonian one) has some satellite data that validates sailors’ reports of
ship-killing waves.

Mariners who survived similar encounters have had remarkable stories to tell. In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick described as “a great wall of water

Another item in the latest Industrial Physicist is a piece on understanding the uncertainties in global warming models, and the public policy implications of those uncertainties. It’s well worth a read if you care about global warming in particular or science and public policy in general.

One of the hardest things about ensuring that public policy is based on sound science is that sound science inherently involves uncertainties. Politicians like yes or no answers, but science only gives really reliable answers in the very long term, far longer than the relevant political timescales. In order to make policy based on sound science, politicians have to take uncertainty into account, and allow for the possibility that the policies may need to be adjusted as new information becomes available.

America needs a “Million Nerd March” on Washington.

John Kerry is now a victim of an old prejudice that no civil rights organization has ever been willing to address. Kerry was totally unaware of this old prejudice when he arrived at Kennedy Space Center last Monday for a town hall meeting at Kennedy Space Center on Florida

America needs a “Million Nerd March” on Washington.

John Kerry is now a victim of an old prejudice that no civil rights organization has ever been willing to address. Kerry was totally unaware of this old prejudice when he arrived at Kennedy Space Center last Monday for a town hall meeting at Kennedy Space Center on Florida

America needs a “Million Nerd March” on Washington.

John Kerry is now a victim of an old prejudice that no civil rights organization has ever been willing to address. Kerry was totally unaware of this old prejudice when he arrived at Kennedy Space Center last Monday for a town hall meeting at Kennedy Space Center on Florida

Ron Reagan (who wouldn’t have this platform if his last name wasn’t Reagan) just made a speech in which one would never know that embryonic research is perfectly legal in this country. I was also struck by this sophistry this morning listening to NPR, when they talked about “restrictions” on such research under the Bush Administration. I don’t agree with the President’s policy, but this is no more “restricting” such research than not funding artists by the NEA is “censorship.”

The policy is that no federal funds will go to such research, not that it is forbidden. But if they told the truth about that, they probably wouldn’t get the political pull that they hope to, and overthrow the evil Bush administration, that ostensibly forbids research that might have saved Ron’s dad (not).

…at the thought that commenter “Brian” from this post teaches undergraduates.

Scroll down a ways, and be amazed.

[Update a few minutes later]

I should add, that there’s another howler there:

Regarding Newton’s second law of motion, F=ma is just fine for all physics short of things traveling greater than 0.95 the speed of light, or quantum effects.

He’s apparently confused, thinking that I’m referring to Einstein’s Special Relativity version of Newton’s Second Law, in which rest mass is converted to true mass via the factor gamma, which is a function of velocity, or F = dp/dt where p = m*v, or in the Einsteinian version, p = gamma*m*v.

Gamma is a function of velocity. It’s 1/(1-v^2/c^2)^1/2 (or in words, it’s the inverse of the square root of one minus the ratio of velocity squared over the speed of light squared). For low velocities, it’s one divided by the square root of one minus a tiny number, or simply one, so at low velocities, mass equals mass. But for high velocities, you’re starting to divide one by a very tiny number (as the difference between 1 and velocity squared over c squared becomes infinitesimal), so gamma blows up to be a huge number. That’s why mass approaches infinity as its speed approaches that of light.

As I pointed out in the other thread, in the Newtonian case it is simple to take the derivative:

F = dp/dt = d(mv)/dt = m*dv/dt + v*dm/dt. But dv/dt is acceleration, so we get:

F = ma + v*dm/dt.

The Einsteinian case is a much more complicated derivative, because it’s a much more complicated function of velocity. But it’s not relevant, since we’re not talking about near-light speeds. The fact remains that Newton’s Second Law is F = ma + v*dm/dt. The only reason that we always see it as the more simple (and incorrect) F = ma, is that this is a special case in which the mass is constant (the derivative of a constant is zero, and the second term goes away). This is the case for most physics problems, but it certainly isn’t for rocketry, in which the vehicle is ejecting mass (that’s what makes it go).

Anyway, as I said, it’s very disturbing that this person is teaching anyone, let alone undergrads.

[Update at noon Eastern]

Professor Hall, who does teach undergrads as well as grads (and I’m glad of it), expands on his comment via email:

I think Brian’s a bit of a putz in his comments. However, he’s right about F=ma and F=dp/dt. Derivation of the rocket equation is a little tricky to work out, as you say. However, the chain rule does not lead to the correct equation.

In the 2nd law,

F = dp/dt

F is the sum of all applied forces, and p=mv is the linear momentum of the particle of mass m.

If you apply the chain rule to this equation, you get

F = m dv/dt + v dm/dt

as you noted.

However, in order for the chain rule to make any sense here, the two v’s must be the same v. What v is it?

If it’s the velocity of the particle, then this equation can’t apply to a rocket, since it couldn’t lift off the ground. On the ground, v is zero, and initially dv/dt is zero, so F is zero. If F is zero, the linear momentum cannot change, so v remains zero.

If it’s the velocity of the mass leaving the rocket, then initially F = v*dm/dt, which is essentially correct. However, the v in the dv/dt term is clearly not the velocity of the mass leaving the rocket. It’s supposed to be the velocity of the rocket.

The correct derivation of the rocket thrust equation uses a control volume approach, which is essentially a summation of Newton’s 2nd law over a continuum of particles of different velocities (the rocket and the propellant clearly have different velocities).

This leads to the following vector equation for rocket motion

F + ve dm/dt – vehat A (Pe-Pa) = ma

The terms on the left comprise the sum of all external forces acting on the
rocket.

F includes all the forces such as gravity, drag, ….

The term ve dm/dt is the thrust due to the rocket, where ve is the exhaust velocity and dm/dt is the mass flow rate (negative number, since m is the mass of the rocket, which is decreasing). The vehat A (Pe-Pa) term is the pressure force. Vehat is a unit vector in the direction of ve, Pe is the exhaust pressure, and Pa is the atmospheric pressure.

I’ll just add that a) I’m glad that at least some of my readers and commenters are smarter than me and b) while I didn’t say that the chain rule led to the rocket equation, I did imply it, and that was a mistake, and c) I had known that at one time, but it’s been a long time.

And we are in agreement that Brian is a putz.