Often in policy debates I find myself facing a broad general statement, such as “Wireless is just as good for everyone as wireline, just look at how the market has adopted it.” Or “ISPs would never block or degrade service because they would lose customers.” Point to a counter example, e.g., “Verizon’s effort to replace wireline with Voicelink on Fire Island was a total flop” or “But Comcast, AT&T, Verizon and other ISPs have deliberately allowed Netflix quality to degrade as a negotiating strategy” and the response is invariably “Oh, that’s just an anecdote and you can’t base rules on anecdotal evidence.”
Oddly, this throws most people into a tizzy of confusion because (a) they vaguely remember learning something about anecdotes not being proof or something; (b) everyone always says anecdotes aren’t proof; but (c) the general statement is clearly false based on real world experience. People know that “it’s only an anecdote, therefore it doesn’t count” is a bull$#@! answer, but they can’t explain why. Hence confusion and much bull$#@! going unchallenged in policy.
In logic, we refer to this as “The Problem of the Black Swan.” No, this has nothing to do with the somewhat racy but very artsy so that makes it OK movie starring Natalie Portman. And, while it is the inspiration for the book by Nassim Nicholas Taleb, it actually means something different. “The Problem of the Black Swan” is a demonstration of the problem of reasoning by induction and falsifiabilty. You cannot prove all swans are white just by finding a white swan, but you can disprove all swans are white by finding a single black swan.
While I don’t normally use this blog to teach Logic 101 type stuff, application (and misapplication) of the “Problem of the Black Swan” comes up so often that I will delve into this below. By the time we’re done, you will be able to explain to people who pull that “oh, an anecdote isn’t evidence” crap exactly why they are wrong. You’ll also be able to apply the “anecdote rule” properly so that you don’t get caught in any embarrassing errors.
Elucidation below . . .