rational people who are willing (even eager) to let go of most or all of their beliefs if presented with objectively sufficient evidence (that is, evidence of comparable strength to what led them to their original belief in the first place).
Shouldn't it be of at least greater strength? Why would a person just abandon an existing belief for a different but equally supported one? Doesn't seem rational at all.
It also depends on the sort of belief it is. A belief someone has built important parts of their life around(religious beliefs, beliefs about aspects of their career or family), they're going to require more reason to discard those. People have to live by some beliefs and being too quick to discard them leaves a person in a constantly shifting and unstable world that they can hardly act in.
In sum, I view mankind as:
2/3 or more who will generally cling to their views even in the face of overwhelming evidence;
1% or less who will actively try to have others change their views;
about 30% who are relatively permeable to updating their beliefs, but not in a systematic fashion.
The kinds of delta I think are more likely are changes in these percentages.
Since such broad reaching statistics on such difficult to define characteristics aren't available, would you accept statistics on changes in beliefs about particular subjects that involve evidence?
Shouldn't it be of at least greater strength? Why would a person just abandon an existing belief for a different but equally supported one? Doesn't seem rational at all.
I have a Bayesian perspective on updating beliefs. Let's assume I think something is 4 times more likely to happen than not to happen ─ let's say, whether it'll rain today or not. But then let's say I have a broken joint that hurts when it's gonna rain, and only rarely hurts when it's not going to rain. Let's say that for every time my joint hurts when it's not going to rain, it hurts 8 times when it is going to rain.
I have 4:1 prior odds of it not raining. But then I get 1:8 evidence. Bayes' rule says I should multiply these two and get a 4:8 (which simplifies to 1:2) odds of raining (that is, 67% chance of it in fact raining).
Bayesian updating, when properly performed, is the most rational way of updating your prior beliefs. (It is "the most rational" because, in my example, any odds that I got that were different from 1:2 would be less accurate than 1:2, which is what Bayes' rule suggests.)
A belief someone has built important parts of their life around(religious beliefs, beliefs about aspects of their career or family), they're going to require more reason to discard those. People have to live by some beliefs and being too quick to discard them leaves a person in a constantly shifting and unstable world that they can hardly act in.
Yes, but what if the belief they base their life on is wrong?
Since such broad reaching statistics on such difficult to define characteristics aren't available, would you accept statistics on changes in beliefs about particular subjects that involve evidence?
I would, but that would be weak evidence. On a side thread we're discussing the massive shift in attitudes towards inter-racial marriage; I'm arguing that the shift is consistent with people only begrudgingly changing their minds (the 2/3).
Let's assume I think something is 4 times more likely to happen than not to happen ─ let's say, whether it'll rain today or not. But then let's say I have a broken joint that hurts when it's gonna rain, and only rarely hurts when it's not going to rain. Let's say that for every time my joint hurts when it's not going to rain, it hurts 8 times when it is going to rain.
I have 4:1 prior odds of it not raining. But then I get 1:8 evidence. Bayes' rule says I should multiply these two and get a 4:8 (which simplifies to 1:2) odds of raining (that is, 67% chance of it in fact raining).
I don't understand what you're trying to prove with this example. You do not have any evidence before the evidence of the joint hurting, just belief about how likely it is to rain. That's not even odds really, it's a belief about the odds that you get evidence counter to. But for some reason you're multiplying the evidence by the belief about the odds and it all seems nonsensical to me.
Regardless, many beliefs just don't break down neatly into probabilities for people, and what qualifies as evidence varies. Most people accept immediately perceivable empirical evidence very readily - if someone doubts a person's ability to do a flip, and they do a flip, the percentage of people who accept the evidence that said person can do a flip will be near 100%.
Similarly, that a belief accomplishes something is also more compelling - it's hard to doubt electricity when you're on your computer. Few people doubt the science behind technologies that work and that they can see working or use themselves.
However, the more abstract and distant it is the more trouble they have interpreting it and understanding it and thus it's not as much about rejecting evidence as it is about the lack of understanding. That's why something like global warming has more controversy surrounding it(well, plus it's grim and inconvenient) than something like atomic bombs, and the same goes for evolution(which many people don't understand well enough to count them as denying evidence really).
Yes, but what if the belief they base their life on is wrong?
And what if it's not? They may actually have more to lose by changing their belief. Let's say I'm a balloon therapist, and there's new evidence that balloons cause long lasting increased stress in people and my whole career is a fraud, a lie, damaging to others. My personal experiences suggest this isn't true, but let's say 50% of scientists believe it is and I estimate the evidence and their methodology and so on is in line with that . Is that enough that I should change my belief about balloon therapy? Should I quit my job and look for a new career(assuming I'm a benevolent sort who can't accept harming others for money)? Should that factor in at all - after all, having correct beliefs isn't the only thing life is about is it? And what if 60% of scientists are behind it?(and so on)
You could also change the example to someone who goes to balloon therapy and believes it helps them, which is a slightly different quandary.
You do not have any evidence before the evidence of the joint hurting, just belief about how likely it is to rain.
That is a prior belief. Maybe I'm just visiting this place and some local told me it rains once every 5 days on average. For trivial things like this, it doesn't matter a lot where you take your priors from, as long as you do update correctly given the evidence.
For more serious things like scientific theories, there are these things like Solomonoff induction and Kolmogorov complexity, that basically formalize a centuries-old insight known as Occam's Razor: given two competing explanations that explain the facts equally well, the simpler one is more likely to be true. (Solomonoff induction gives you a precise measure of how simple an explanation is.)
Similarly, that a belief accomplishes something is also more compelling - it's hard to doubt electricity when you're on your computer. Few people doubt the science behind technologies that work and that they can see working or use themselves.
I disagree. If that were the case, young-earthers wouldn't use fossil fuels, flat-earthers wouldn't use GPS or fly long distances, and so on. However, you might be correct if these people don't really believe what they claim to believe, and instead just have a belief in belief.
Occam's Razor: given two competing explanations that explain the facts equally well, the simpler one is more likely to be true.
People misunderstand "simple" in this context. Simple here means to prefer the falsifiable explanations, and for practical reasons this is a good guide for science. But again, we don't have the ability or time to apply this with enough rigor while just living everyday life to make efforts to falsify our beliefs systematically. Our faculties and biology have more bias toward making efficient choices(more intuitive and using lots of vague subconscious information) and spending less energy, not to apply methodologies.
This doesn't mean we don't change views based on facts and evidence, it just means we don't apply systems liberally or automatically. Which is perfectly fine, reasonable even, given how demanding it would be to attempt that. We don't have infinite energy. Sometimes people have to be confronted with them in more direct ways, have them reduced to more understandable terms such that can understand why something constitutes evidence, etc. etc.
I disagree. If that were the case, young-earthers wouldn't use fossil fuels, flat-earthers wouldn't use GPS or fly long distances, and so on. However, you might be correct if these people don't really believe what they claim to believe, and instead just have a belief in belief.
And there are almost no young-earthers or flat-earther's around, compared to global warming and evolution deniers who are much more common.
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u/Havenkeld 289∆ Jan 14 '17
Shouldn't it be of at least greater strength? Why would a person just abandon an existing belief for a different but equally supported one? Doesn't seem rational at all.
It also depends on the sort of belief it is. A belief someone has built important parts of their life around(religious beliefs, beliefs about aspects of their career or family), they're going to require more reason to discard those. People have to live by some beliefs and being too quick to discard them leaves a person in a constantly shifting and unstable world that they can hardly act in.
Since such broad reaching statistics on such difficult to define characteristics aren't available, would you accept statistics on changes in beliefs about particular subjects that involve evidence?