dammit, you could have told me that before I spent so much time building this flying machine made of bone and flesh...

If the same majority of smart people as stupid people are conservative then the statement that "Not all conservatives are stupid, but most stupid people are conservatives." is actually completely irrelevant, but I don't think that anyone believes otherwise. If there is a positive correlation between intelligence and the truth of one's beliefs (a claim the truth of which is probably assumed by most people to be true for any definition of intelligence they care about) then the average intelligence of people who hold a given belief is entangled with the truth of that belief and can be used as Bayesian evidence. Evidence is not proof of course, and this heuristic will not be perfectly reliable.

every (modern) atheist knows his or her atheism is a product of scientific understanding

This is wrong.

Even presuming that you're speaking very informally, and your statement shouldn't be interpreted literally, it's STILL wrong.

It's amazing how many supposedly rationalist movements fall into the trap of crippling "reverse stupidity." Many in the atheist movement would not have you make positive pronouncements, not have you form organizations, not have you advocate, not have you adopt symbols or give the movement a name, not have you educate children on atheism, and so on, all because "religion does it." I think in the case of atheism the source is unique: every (modern) atheist knows his or her atheism is a product of scientific understanding but few atheists are willing to admit it (having taken up also the false belief that some things are "outside science"), so they go looking for other reasons, and "reverse stupidity" offers such reasons in abundance.

"... you have to directly challenge the arguments of Nick Bostrom or Eliezer Yudkowsky post-2003."

Just what the heck happened in 2003? In any experimental field, particularly this one, having new insights and using them to correct old mistakes is just part of the normal flow of events. Was there a super-super-insight which corrected a super-super-old mistake?

Evidence is like gravity. Everything is pulling on everything else, but in most cases the pull is weak enough that we can pretty much ignore it. What you have done, Caledonian, is akin to telling me the position of three one-gram weights, and then asking me to calculate the motion of Charon based on that.

If not, why not? I gave you plenty of evidence.

Caledonian, you gave evidence, but you certainly didn't give plenty of it. I see you ignored the part of my post where I talked about how to quantify evidence. The important question isn't whether or not we have evidence; it's how much evidence we have.

Let me make an analogy. I can define sugar as sucrose; a specific carbohydrate whose molecular structure you can view on wikipedia. I might say that a substance is "sugary" if it contains some sugar. But by this definition, almost everything is sugary, so I hasten to point out that the important question is how sugary it is, and we might define this as the fraction of its mass which consists of sugar.

If, after I have pointed this out, you offer me some sugar cookies containing 1 molecule of sucrose, and then defend yourself by saying that according to my definition, they are indeed sugary, you are being obnoxious. I already told you how to quantify sugariness, and you ignored it for rhetorical reasons.

michael vassar: You're right when you say a correlation of intelligence with liberalism is evidence for liberalism, but that's not because the stupid people are conservative, it's because the smart people are liberal. At least I think that's what Eliezer meant.

I still believe in Global Warming. Do you?

-Ted Kaczynski, The Unabomber

-Heartland Institute billboard

From the press release:

1. Who appears on the billboards?

The billboard series features Ted Kaczynski, the infamous Unabomber; Charles Manson, a mass murderer; and Fidel Castro, a tyrant. Other global warming alarmists who may appear on future billboards include Osama bin Laden and James J. Lee (who took hostages inside the headquarters of the Discovery Channel in 2010).

These rogues and villains were chosen because they made public statements about how man-made global warming is a crisis and how mankind must take immediate and drastic actions to stop it.

2. Why did Heartland choose to feature these people on its billboards?

Because what these murderers and madmen have said differs very little from what spokespersons for the United Nations, journalists for the “mainstream” media, and liberal politicians say about global warming. They are so similar, in fact, that a Web site has a quiz that asks if you can tell the difference between what Ted Kaczynski, the Unabomber, wrote in his “Manifesto” and what Al Gore wrote in his book, Earth in the Balance.

The point is that believing in global warming is not “mainstream,” smart, or sophisticated. In fact, it is just the opposite of those things. Still believing in man-made global warming – after all the scientific discoveries and revelations that point against this theory – is more than a little nutty. In fact, some really crazy people use it to justify immoral and frightening behavior.

Interestingly, science is the first thing mentioned in the next section:

3. Why shouldn’t I still believe in global warming?

Because the best available science says about two-thirds of the warming in the 1990s was due to natural causes, not human activities; the warming trend of the second half of the twentieth century century already has stopped and forecasts of future warming are unreliable; and the benefits of a moderate warming are likely to outweigh the costs. Global warming, in other words, is not a crisis.

"You're right when you say a correlation of intelligence with liberalism is evidence for liberalism, but that's not because the stupid people are conservative, it's because the smart people are liberal."

If you assume the population is partitioned into liberals and conservatives, a high percentage of stupid conservatives implies a high percentage of smart liberals, and vice-versa. If smart liberals are Bayesian evidence for B, then smart conservatives must be Bayesian evidence against B (note that 'smart' here is relative to the average, not some absolute level of smartness).

How about this for a precise definition: A is evidence about B if p(A | B) != p(A | ~B).

Of course, by this definition, almost everything is evidence about almost everything else. So we'd like to talk about the strength of evidence. A good candidate is log p(A | B) - log p(A | ~B). This is the number that gets added to your log odds for B when you observe A.

Beware of feeding trolls. If the one can offer naught but flat assertions, you may be better off saying, "Let the audience decide." If you engage and offer defense to each repeated flat assertion, you encourage them to do even less work in the future, since it offers the same attention-reward.

"""A car with a broken engine cannot drive backward at 200 mph, even if the engine is really really broken."""

Wrong!

"When the player's truck is put into reverse, the truck will accelerate infinitely; however, the truck will halt instantly when the reverse key is released."

Matthew: Just me after 2003, not Bostrom.

I call the experience my "Bayesian enlightenment" but that doesn't really say anything, does it? Guess you'll have to keep reading Overcoming Bias until I get there.

Flying saucer cultism was helped along by secret Cold War technological advances that were accidentally witnessed by civilians.

For example, the famous 1947 Roswell incident was the crashing of an American strategic reconnaissance super-balloon that was supposed to float over the Soviet Union and snap pictures, which would then be recovered many thousands of miles away. That's why it was made out of the latest high-tech materials that were unfamiliar to people in small town New Mexico in 1947.

The KGB used to generate flying saucer stories in Latin America to discredit actual sightings of the re-entry of a Soviet "partial-orbit" missile that was being tested in order to allow a surprise attack on the U.S. from the South (the NORAD radar assumed a Soviet attack would come over the Arctic). KGB agents in Latin America would phone in flying saucer reports to newspapers to make honest witnesses of the Soviet missile test look like lunatics.

For any that may be genuinely confused: If you read What is Evidence?, An Intuitive Explanation of Bayesian Reasoning, and A Technical Explanation of Technical Explanation, you will understand how to define evidence both qualitatively and quantitatively.

For the rest of you: Stop feeding the troll.

To say it abstractly: For an event to be evidence about a target of inquiry, it has to happen differently in a way that's entangled with the different possible states of the target. (To say it technically: There has to be Shannon mutual information between the evidential event and the target of inquiry, relative to your current state of uncertainty about both of them.) Entanglement can be contagious when processed correctly, which is why you need eyes and a brain. If photons reflect off your shoelaces and hit a rock, the rock won't change much. The rock won't reflect the shoelaces in any helpful way; it won't be detectably different depending on whether your shoelaces were tied or untied. This is why rocks are not useful witnesses in court. A photographic film will contract shoelace-entanglement from the incoming photons, so that the photo can itself act as evidence. If your eyes and brain work correctly, you will become tangled up with your own shoelaces.

And you haven't tried to define meta-evidence at all.

If I do find someone whose statement seem to reliably anti-correlate with reality, am I justified in taking their making a statement as evidence that the statement is false?

We can know a great deal about the fraction of people who think B, and it still cannot serve even as meta-evidence for or against B. There is an ongoing confusion here about the difference between evidence and meta-evidence.

No. From a Bayesian perspective, there is no difference other than strength. This is, of course, different from saying that the truth is what the authorities say it is, but I think that's what you're hearing it as.

"No. The "unless" clause is still incorrect. We can know a great deal about the fraction of people who think B, and it still cannot serve even as meta-evidence for or against B."

This can't be right. I have a hundred measuring devices. Ninety are broken and give a random answer with an unknown distribution, while ten give an answer that strongly correlates with the truth. Ninety say A and ten say B. If I examine a random meter that says B and find that it is broken, then surely that has to count as strong evidence against B.

This is probably an unnecessarily subtle point, of course; the overall thrust of the argument is of course correct.

Clarification: Just yudkowsky after 2003 or yudkowsky and bostrom together, perhaps sharing the same mistake? It would be usefull to know so I don't make the same mistake, et al.

I'm with McCabe-- what was the epiphany?

Many people are unsatisfied with their monogamous relationships, therefore polyamory must be great?

"Not all Conservatives are stupid, but most stupid people are
Conservatives." (The British Conservative Party was the brunt of this quip by J.S. Mills.) It helps to Venn diagram this. I find that many stupid conservatives assume that conservatives are the majority, which leaves few stupid people to be liberals or anything else (although a majority of Liberals are assumed by stupid conservatives to be stupid people). But if conservatives are not a majority, there are many stupid people who MIGHT or MIGHT NOT be liberals. I assume there are plenty of stupid people to go around between the conservatives, liberals and other groups. If conservatives ARE the majority and most stupid people are conservatives, but liberals are a very sizeable minority, you would expect a lot of Smart People Who Are liberals. To quote Karl Rove: "As people do better, they start voting like Republicans - unless they have too much education and vote Democratic, which proves there can be too much of a good thing." Presumably the Republicans have a lock on the rich and stupid vote, or at least the rich and uneducated.