The Datum Fallacy

Nobody uses the term datum anymore, and that's tragic. Our failure to use the word will lead to biblical floods, tyranny, cats and dogs living together…

Seriously. We need to bring datum back.

For the word nerds, the etymology: Datum is not a baby android on Star Trek. The word comes from the Latin for “given,” as in something accepted. A fact, a tiny piece of truth. Fact checking groups like factcheck.org and politifact.com can help steer us straight when candidates veer off the straight road of truth. But a fact is only a point on that road.

In other words, a fact is a datum, one little dot on the scatter plot of truth. It’s like the blind man pressing his finger against the soft flesh of an elephant’s trunk and thinking that spot tells him all he needs to know about elephants.

Mistaking a datum for reality triggers a logical foul I call the datum fallacy: mistaking a single fact for the larger truth.

Senator Jim Inhofe committed the fallacy when he tried to rebut climate science by throwing a snowball on the Senate floor last year. The Eastern Seaboard was having a pretty cold winter, and there was indeed snow in Washington on February 26, 2015, the day the Senator held his little weather demonstration. The weather on one day in one place counts as a nice frosty datum. But that datum is just one dot of information in a global tsunami of data. Snow in Washington on that day was a fact. But instead of revealing the truth, that dot obscured it; when you look at the weather throughout the globe for the entire year, 2015 was the warmest on record.

We commit the data fallacy when we hear about a shooting and assume a crime wave (violent crime is way down since the 1990s, and the murder rate is near a historic low).

Want to avoid the datum fallacy and destroying civilization as we know it? Widen your perspective in space and time. Does this datum match other facts elsewhere? Does it show an increase or a decrease?

In the meantime, start using datum every chance you get. It’s a given.