That is, I don’t believe in assigning numerical values to them. That practice seems to me a mendacious attempt to quantify the unquantifiable.
This came up because of this email from a friend today:
When I was in high school, I once wondered whether a 50% chance of rain meant: A. there is a 100% chance that it will rain on 50% of the city or B. there is a 50% chance that it will rain on 100% of the city. I think the real answer is that there is a 50% chance it will rain at least somewhere in the city (which is actually less than a 50% chance that it will rain in any one place). It’s painfully obvious that my chances at a STEM major in college were much lower than 50%!
For my part, I don’t believe there’s such a thing as a 50 percent chance of rain, period. I don’t mind someone saying, “I have as much reason to believe it will rain today as I have reason to believe it won’t.” But don’t insult me by attaching a number to it. You don’t know enough to attach such precision to the matter.
You want to assign a numerical value to the likelihood of rain on Thursday? Here’s my advice: Wait until Friday. Look back, and if it rained on Thursday, there was a 100 percent chance. If it didn’t, there was a 0 percent chance. The rest is nonsense.