popular opinion as evidence
April 11, 2014 at 6:37 pm
(This post was last modified: April 11, 2014 at 6:51 pm by Coffee Jesus.)
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.
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.
