popular opinion as evidence

[tor]

No it does NOT increase the probability of SPACE SHIP flying. Why are you saying this?

[MindForgedManacle]

Okay, what? I don't want to be mean in case English isn't your first language, but I cannot understand you there. We've been talking about how evidence for something increases the probability it's true. Claims are evidence. Therefore claims increase the probability of something being true. But again, this doesn't make them likely at all. I've given you several examples of how this is the case, but I can't help but notice your lack of response to them.

[tor]

The claims are not evidence. If somebody seen ghosts is not evidence of ghosts. But it could be evidence of something else.

[MindForgedManacle]

You've just contradicted yourself now...

[tor]

You've just contradicted yourself now...

Where?

[MindForgedManacle]

The claims are not evidence.

If somebody seen ghosts is not evidence of ghosts. But it could be evidence of something else.

There.

[tor]

The claims are not evidence.

If somebody seen ghosts is not evidence of ghosts. But it could be evidence of something else.

There.

Are claims about ghost increase the likehood of ghost existing? No.

[archangle]

I think whether popular opinion is evidence depends on the hypothesis.

An observation supports the hypothesis if the conditional probability of the observation in the event that the claim is true, P(O|T), is greater than its probability in the event that the claim is false, P(O|F). That is, if there is a mechanism by which the claim being true can influence the probability of the observation, which in this case is whether people think the claim is true.

It's not as simple as equating frequency of belief with likeliness of truth, for the probability could be unusually high or low for either the true or false condition. For example, suppose that hundreds of people throughout history had a divine being reveal to them that "There actually is a hell, but the people who believe in a hell are the people who will be damned." Being disposed to save others from this fate, they would keep this secret.

Also important is how the opinion is distributed. A lot of people believe in the Abrahamic god. It's possible that some of them came to this conclusion because they witnessed an undeniable instance of divine intervention, the nature of which suggested Yahweh. But if that really was how people came to believe this, we would likely see Judeo-like religions originating from isolated cultures that were never in contact. Instead we see Christianity spreading as we would expect any other unfounded belief to spread. (This is also how some scientific ideas spread, but that's okay because we have other methods for evaluating those.) Not to mention that Christianity was largely spread through coercion, and that religiostity is correlated with higher fertility.

Evidence is something you can give people that do not think like you and they can come up with a similar conclusion. The conclusion may not exactly fit, but it will be the same. Like life started on earth as compared to life started in space. They seems polar opposites, but they are similar.

Of course rational don't have to address irrational people.

[Coffee Jesus]

tor, I actually started this thread to counteract the common apology, "Why would so many people believe this if it weren't true?"

I acknowledge that there is a very basic level of reasoning behind this. If there was a god, it might reveal its existence to people through divine intervention, so the existence of god would provide a mechanism that could result in people believing in gods.
One problem is that there are many other potential explanations, but the even bigger problem is the other mechanisms we already know are in operation. For example, I recall an expiment in which hitting people over the head caused them to have religious hallucinations. Until we actually know how much of the belief can be accounted for by known mechanisms like hallucinations, peer pressure, liars, and "miraculous" flukes, we cannot determine the probabilities. It's quite possible that, after controlling for those variables, we would prove that first-hand witnessing of divine intervention plays no role in inducing these beliefs.

So, in effect, you're right.