Your argument seems to conclude that:

It is impossible to reason with unreasonable people

Agreed. Now what?

Ostensibly your post is about how to swing the ethos of a large group of people towards behaving differently. I would argue that has never been necessary and still is not.

A good hard look at any large political or social movement reveals a small group of very dedicated and motivated people, and a very large group of passive marginally interested people who agree with whatever sounds like it is in their best interest without them really doing too much work.

So can rationality work on a large scale? Arguably, it always does work. I rarely hear political or social arguments that are obviously (to everyone) pure hokum. If you look at how the last 4 U.S. presidents campaigned, it was always on "save you money" talking points and "less waste, more justice" platform. All rational things in the mind of the average person.

I think however your implication is that rationality is not always obviously rational. Well friend, that is why you have to completely understand the implications of rational decision making in terms that the majority can agree on in order to describe why they are better decisions. You often have to connect the dots for people so that they can see how to get from some contrarian or "non-intuitive" idea to their goal of raising a happy family.

This is the essence of "selling." Of course spinners and politicians sell lots of crap to people by telling half truths, overcomplicated arguments or simply outright lying. These are obviously disingenuous. If you need to lie to sell your ethos it is probably wrong. That or you just aren't wise enough to make it comprehensible.

However, neither of these imply that intelligence, science, and rationality, as a practical matter, are the best way to get things done by individual people operating in the year 2009.

I am not sure science belongs in that sentence. The application of science is an assumed part of my everyday life in the form of technology. Sure, I am not whipping up new chemicals to help me get through today, but I use computers, pens, clothing, dishwashers...

Intelligence certainly has a practical threshold. If you have no intelligence at all you cannot thrive in a world of computers, pens, clothing, dishwashers... On the other hand, technology has allowed some areas to lower their intelligence thresholds. People who have severe mental disabilities can function in relatively normal lifestyles. I see this as a good thing.

Rationality is probably the least necessary for everyday living, but I wonder if it works the same way as science and intelligence: Is applied rationality what we see day in day out? If something applied rationality to the world around us, would our personal lives get easier/better?

I am not really disagreeing with what you said. I guess I am more looking for clarification about what you meant by the quoted sentence above.

So far as I am aware, no group of people has managed to achieve anything even remotely similar using, not only rationality, but any skill involving deliberative thought, as opposed to skills such as yelling at huge crowds of people.

I would offer a reactionary counterpoint and say that most people who achieve things that similar were using deliberative thought. I have about as much evidence as you showed in your post. I really think you are underplaying Hilter's abilities. He deliberately set out to achieve a particular goal and succeeded. It's not like he accidently tried to take over the world. The British Empire, the Roman Empire, and any other large ruling body was also acting deliberately. I am not a big history buff, so I cannot think of many others. Mao? Stalin?

Today the large conquerers could be translated into people with money. Bill Gates, Warren Buffet, et al were able to systematically make money. They weren't lucky, unintelligent, crazy, or anything like that. They are smart, driven people with a specific goal who have succeeded.

"People use armed force all the time with their neighbors."

This was not phrased correctly. It should have said, "used," and it should have included the threat. Back when governments were weaker and there was more crime and fewer educated people, courts weren't great at punishing violence, so violence and the threat thereof were widespread - look at the historic power of organized crime. This remains true today, but it's less true because our ability to enforce the law has improved.

People used violence when it was effective and they wouldn't get in trouble with other, more powerful people. Nations used violence when it was effective and they wouldn't get in trouble with other, more powerful nations. Nuclear weapons simply changed how much trouble they'd get into, just as better law enforcement monitoring and a lower general crime rate, and falling cultural acceptance have changed how likely people are to get into trouble when they use force. I really don't think the two examples are as different as you claim they are.

"People use armed force all the time with their neighbors."

No, they really, really don't. Compared with either a). governments or b). people in the ancient world, violence nowadays is really rare. For governments, consider that, in 1900, it was common for a country to spend 10% of its GDP on its military; how many people do you know who spend 10% of their gross pre-tax income on weapons to fight their neighbors with? For people in the ancient world, consider that the murder rate for males before they reached age 25 in pre-agricultural societies was something like 30%; nowadays it's something like 1%.

"On a separate point, while the Nazis had some crazy beliefs, they still excelled in a number of important areas."

Agreed, but what I was saying was that none of these areas involved general intelligence, science, rationality or deliberative reasoning.

"So let's be glad they underrated rationality."

Agreed. My thesis in this post was that rationality, intelligence, and science are the most important factors on the level of a country, but not on the level of an individual. Hence, the Nazis, who were really irrational, succeeded at taking over Germany, but then failed at taking over the world largely through irrational stupidity.

"Those "native forces" were Neolithic people,"

Did you even read the article? They had twenty thousand people who were armed with rifles, which means that, even if they had a backwards culture, their technology was very far from Neolithic.

"Romans claim 50:1 casualty ratios for conquest of Gaul."

All numbers that ancient historians give for enemy armies are highly suspect in general (everyone wanted to exaggerate their triumphs).

"Hitler rose to a place of prominence in the early years of the party (1919 - 1923) largely as a result of his considerable skills in oratory, organization and promotion."

Yes- notice how rationality and intelligence are not on that list.

OK, so my favorite man-with-a-hammer du jour is the "everyone does everything for selfish reasons" view of the world. If you give money to charity, you do it for the fuzzy feeling, not because you are altruistic.

What would you propose as the three factual claims to test this? I'm having a hard time figuring any that would be a useful discriminant.

Thinking about this a bit, it seems most useful to assert negative factual claims, ie: "X never happens".

In ~400 the Western parts of the empire existed as it had for >200 years. By 450 it was effectively restricted to Italy and parts of southern Gaul, and in 476 it was officially terminated by the death of the last Western Emperor.

Not quite accurate; in 376 a big bunch of barbarians half-forced, half-negotiated their way into the Empire, became disloyal subjects, and subsequently pillaged the Balkans and defeated killed an (Eastern) emperor and his army. So it's better to say that the Western Empire declined almost entirely during the 100 years 376-476. (Politically, militarily, and on a local rule level this is true. Culturally the collapse did take longer in some places.)

open != unlimited. But that's a margin that I would push pretty hard, relative to others.

Ruling out unpopular measures is tantamount to giving up on your job as a politician; the equivalent of an individual ruling out any avenues to achieving their goals that require some effort.

Much as rationality in an individual consists of "shutting up and multiplying", i.e. computing which course of action including those we have no taste for yields the highest expected utility, politics - the useful part of it - consists of making necessary policies palatable to the public. The rest is demagoguery.

And open immigration policies