Pareto, shmeto - it's all 80/20 to me

Jim Collins (the guy who wrote Good to Great, that book about some companies that were good, became great, and some of which—Circuit City and Fannie Mae, for two—are now bankrupt...) once said that each of his books come out of questions. Someone asks him a question to which he doesn't know the answer, and next thing you know...

A question was posed to me today: what kind of gibberish is "80/20"? Now, I knew the basics of the 80/20 rule—80% of your results come from 20% of your input (be it profits and customers, comments and readers, or whatever). But, upon further reflection, I realized I had no idea where that rule came from.

Turns out there was this guy, Vilfredo Pareto, in 19th century Italy, who posited that 20% of the population owned 80% of the land. And so it was.

Now it also appears that it those two numbers don't have to add up to 100. It could be 80/10 or 90/20. But the rule of thumb is 80/20.

And you all know where "rule of thumb" comes from, right?

that's Latin for...

You know when you're arguing with someone, and you know you're right and they're wrong—but all of a sudden you're defending yourself for something wrong that you did? And you're sitting in jail, thinking to yourself, "Wait. How did this happen? Tiffany's the one who said she could hot-wire the car in under 4 seconds. How come we're fighting about the time last year when I forgot to dope the doberman?"

It's a nasty bit of argumentative "tactics"—and it even has a name. "Tu quoque," Latin for "you, also."

Turns out there's a whole host of related argument derailers to be on the look-out, grouped under "ad hominem," which means (those Latin—busy, busy) "against the man."

There's the abusive ad hom way to go: "when an attack on the character or other irrelevant personal qualities of the opposition—such as appearance—is offered as evidence against her position." Often called the "red herring" argument.

Then you've got the circumstantial route: "in which some irrelevant personal circumstance surrounding the opponent is offered as evidence against the opponent's position.... The fallacy claims that the only reason why he argues as he does is because of personal circumstances, such as standing to gain from the argument's acceptance. "

If that's not enough, you can go with the ole reliable, Poisoning the Well:

To poison the well is to commit a pre-emptive ad hominem strike against an argumentative opponent. As with regular ad hominems, the well may be poisoned in either an abusive or circumstantial way.... Poisoning the Well is not, strictly speaking, a logical fallacy since it is not a type of argument. Rather, it is a logical boobytrap set by the poisoner to tempt the unwary audience into committing an ad hominem fallacy...

The underlying fallacy here is that the counter-arguments against the original topic are based on everything but actual arguments (past acts, circumstances, character)—when, as everyone knows, arguments and counter-arguments must stand on their own merit, regardless of the person advancing them (even if she did forget to dope the doberman).