There’s probably an existing logical fallacy that covers this, but I want to discuss what I think of as the fallacy of rare occurrences. This is what happens when people assume that because something has become rare, it can’t have been that bad, it never really occurred, or it could never occur again. (Sometimes they claim all three at the same time, which I find amusing.)
The two best examples I can think of are vaccine-preventable diseases and disease transmission through raw milk.
Recently, raw milk advocates flooded Capitol Hill to demand access to
salmonella, listeria, and E. coli, er, I mean, unpasteurized milk. One aspect of their argument (besides a lack of understanding of what pasteurization does) is a firm belief that these pathogens won’t reappear in the milk supply if we allow raw milk consumption to spread. “Oh, we have better sanitation now!” they cry.
Uh-huh. As if that’s going to keep a healthy-looking cow from giving you something nasty. Thanks for playing. But because most people haven’t encountered someone who’s had brucellosis from raw goat milk or listeria from unpasteurized cow milk, they figure it can’t happen to them. Sure, it’s rare. And when only a few people drink raw milk, the number of people who get sick will be very small, perhaps vanishingly small. But the more people who drink it, the more likely it is.
Me? I’m going to keep myself and my kids healthy by sticking with one of the greatest public health actions ever. Clean water and clean milk for all!
And then, of course, you get the anti-vaccine advocates who claim that they had measles and it wasn’t so bad, so obviously bad things didn’t happen from these diseases, and so why should they have to vaccinate their children?
Let me start with one minor point that always bugs me about that argument: Have you considered the fact that the people who had the serious cases of measles and diptheria and pertussis are currently residing in cemeteries? That’s why they’re not around to tell you how serious those illnesses are.
Obviously, when only a few people get mumps each year, there aren’t going to be a lot of children going deaf. Which means that people forget all the horrible cases of meningitis and deafness that used to result from the mumps. And if you didn’t live through the polio era, it’s easy to forget about people living out their whole lives in an iron lung. It didn’t happen! It wasn’t that bad! It won’t happen again!
Except that it did, it was, and it might. Just because something is rare now doesn’t mean it can’t come back. Eternal vigilance is the price of public health.