The most exciting phrase to hear in science, the one that heralds new discoveries, is not Eureka! (I found it!) but rather, "hmm.... that's funny...." Isaac Asimov

Friday, June 18, 2010

Weeding Out False Positives


Weeds are unwelcome parasites in a garden, taking water, nutrients and light away from plants we want to grow. Individually or in low numbers, they aren’t a concern, but a weed infestation can be devastating. A false positive is a belief that things are connected when in reality they are not. In a way, a false positive is a weed of the mind. Like weeds, false positives seem to sprout naturally. We look for patterns and connections, and we file away memories of what look like cause and effect relationships. False positives are typically harmless, but if there are enough of them, or they are particularly influential, they can lead us astray. In his recent book The Vanishing Face of Gaia, James Lovelock points out that superstition and belief in magic – classic examples of false positives - are long-standing habits of human thought, whereas the scientific method, with its use of observation and measurement to circumvent false positives, is only a few hundred years old.

I had a chance to weed out a false positive three months ago. A person who seemed authoritative told me that it was getting time to plant peas, but that the Farmer’s Almanac said that peas planted on March 21 would rot in the ground. My plan had been to plant peas on just that day, and my first thought was to put it off to another day with a less ominous prediction. After all, it’s a strange world, and maybe the Almanac had some insight on peas and planting dates. But March 21 was a beautiful sunny day, and the seeds went in the ground, albeit with some trepidation on my part. I’m happy to say they sprouted and have produced the bountiful plants in the photo above. Did I tempt fate and get lucky? I don’t think so. More likely, I just stumbled on another pesky false positive and, this time anyway, was able to pull it out.