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TGGP4 comments on How to Convince Me That 2 + 2 = 3 - Less Wrong

53 Post author: Eliezer_Yudkowsky 27 September 2007 11:00PM

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Comment author: TGGP4 28 September 2007 12:07:27AM 1 point [-]

Do we consider it to be evidence in Christianity's favor that more people believe in it than Islam? Does the average IQ of adherents of a religious belief cause it to become more plausible to us?

In the interests of disclosure, I am an agnotheist who was baptized Catholic and raised mainline Protestant, so we're still waiting for Eliezer's requested comment.

Comment author: Sengachi 08 September 2012 08:50:36PM -1 points [-]

People can believe wrong things by the millions (Yay! the Earth is flat), that does not make it right. Stupid people can believe correct things and intelligent people can believe incorrect things. And if you were basing the belief system you believe in on average IQ, you'd go with atheism anyway.

But none of these things are evidence. Something would be evidence even if everybody in the world disagreed. Relativity was true even when every single physicist (a group of rather educated people) just knew that Newtonian physic was truth.

Comment author: arundelo 10 September 2012 07:20:06AM 15 points [-]

People's belief in something is evidence for that thing in the sense that in general it's more likely for people to believe in a thing if it's true. Less Wrongers sometimes use the phrase "Bayesian evidence" when they want to explicitly include this type of evidence that is excluded by other standards of evidence.

One way to think about this: Imagine that there are a bunch of parallel universes, some of which have a flat Earth and some of which have a spherical Earth, and you don't know which type of universe you're in. If you look around and see that a bunch of people believe the Earth is flat, you should judge it as more likely you're in a flat-Earth universe than if you looked around and saw few or no flat-Earthers.

However, people's beliefs are often weak evidence that can be outweighed by other evidence. The fact that many people believe in a god is evidence that there is a god, but (I think) it's outweighed by other evidence that there is not a god.

See also "Argument Screens off Authority".

Comment author: [deleted] 10 February 2015 12:03:11AM 1 point [-]

'People's belief in something is evidence for that thing in the sense that in general it's more likely for people to believe in a thing if it's true'. What's the evidence for this statement?

Comment author: 0ctoDragon 12 August 2015 06:23:34PM 0 points [-]

Something to consider is that if you allow your beliefs to be influenced by the beliefs of others you are in danger of creating a feed back loop. When deciding what to believe based on what others believe you must rule out those who are simply following others as well

Comment author: sciolizer 11 February 2014 06:12:42AM 9 points [-]

Certainly. The probability of Christianity having more followers than Islam is greater if Jesus rose from the dead and less if he did not.

It's not necessarily strong evidence of course. Disavowing Islam has enormous social consequences, so I would expect there to be a large number of Muslims in both the world where Muhammad received the Quran from Gabriel and the world where Muhammad hallucinated. But I still expect there to be more Christians if Jesus rose from the dead than if he did not.

IQ is only weakly correlated to rationality. A much better thing to do is to ask Christians why they believe. If you know the reasons a Christian believes, then the evidential weight of their reasoning will replace the evidential weight that comes from the fact that they believe.

The causal flow looks like this:

Reality --> Reason to believe -> Person believes

By d-separation, once you know a person's reasons for believing, the fact that they believe is no longer useful information to you.

In the interests of disclosure, I am an ex-Christian who spent a year learning Arabic because I believed that God was calling me to be a missionary to Muslims. When I learned Bayes theorem, I attempted to use it to construct an argument that Jesus being divine was more probable than him being ordinary. Needless to say, I didn't get very far before I realized I was falling into the base rate fallacy, and this is what ultimately led to my de-conversion.

Some simple Fermi estimates:

The United States with it’s current population of 300 million has around 5,000 cults. The entire world had a population around 300 million during Jesus’s time, so we can guess that they also had about 5,000 religions. Only ten of them became major world religions (let's say). So the probability of a false religion becoming a major world religion is about 1 in 500. The probability of a true religion becoming a major world religion is near 100%. So the evidential weight of Christianity's large following is about 499 to 1.

If the probability of a randomly selected human rising from the dead is less than 1 out of 500 (and I had to admit that it was substantially less, even when I was a believer), then these two considerations suggest it more likely that Jesus did not rise from the dead.

There's lots of other evidence that could be taken into account. But as a non-believer I don't hesitate to admit that Christianity's popularity counts as positive evidence; I just think the negative evidence adds up to more than the positive evidence.