I was just thinking about this a few days ago when I was flying for the holidays. Outside the plane was a sign that said something like
Warning: Jet fuel emits chemicals that may increase the risk of cancer.
And I was thinking about whether this was a justified double-hedge. The author of that sign has a subjective belief that exposure to those chemicals increases the probability that you get cancer, so you could say “may give you cancer” or “increases the risk of cancer”. On the other hand, perhaps the double-hedge is reasonable in cases like this because there’s some uncertainty about whether a dangerous thing will cause harm, and there’s also uncertainty about whether a particular thing is dangerous, so I supposed it’s reasonable to say “may increase the risk of cancer”. It means “there is some probability that this increases the probability that you get cancer, but also some probability that it has no effect on cancer rates.”
I was just thinking about this a few days ago when I was flying for the holidays. Outside the plane was a sign that said something like
And I was thinking about whether this was a justified double-hedge. The author of that sign has a subjective belief that exposure to those chemicals increases the probability that you get cancer, so you could say “may give you cancer” or “increases the risk of cancer”. On the other hand, perhaps the double-hedge is reasonable in cases like this because there’s some uncertainty about whether a dangerous thing will cause harm, and there’s also uncertainty about whether a particular thing is dangerous, so I supposed it’s reasonable to say “may increase the risk of cancer”. It means “there is some probability that this increases the probability that you get cancer, but also some probability that it has no effect on cancer rates.”
I like this as an example of a case where you wouldn’t want to combine these two different forms of uncertainty