Logically Fallacious: The Ultimate Collection of Over 300 Logical Fallacies (Academic Edition) (Dr. Bo's Critical Thinking Series)

by Bo Bennett

Base Rate Fallacy (also known as: neglecting base rates, base rate neglect, prosecutor’s fallacy [form of]) Description: Ignoring statistical information in favor of using irrelevant information, that one incorrectly believes to be relevant, to make a judgment. This usually stems from the irrational belief that statistics don’t apply to a situation, for one reason or another when, in fact, they do. Example #1: Only 6% of applicants make it into this school, but my son is brilliant! They are certainly going to accept him! Explanation: Statistically speaking, the son may still have a low chance of acceptance. The school is for brilliant kids (and everyone knows this), so the vast majority of kids who apply are brilliant. Of the whole population of brilliant kids who apply, only about 6% get accepted. So even if the son is brilliant, he still has a low chance of being accepted (about 6%). Example #2: Faith healing “works,” but not all the time, especially when one’s faith is not strong enough (as generally indicated by the size of one’s financial offering). Unbiased, empirical tests, demonstrate that a small but noticeable percentage of people are cured of “incurable” diseases such as cancer. Explanation: This is true. However, what is not mentioned in the above is the number of cases of cancer that just go away without any kind of faith healing, in other words, the base rate of cancer remission. It is a statistical certainty that among those with cancer, there will be a perc...