The fallacy of rare occurrences

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.


About mamamara

I'm a 40-something, work-at-home mother of two. I'm pro-vaccine, pro-medicine, pro-science, and an avid reader of information about all of the above, and I want to combine my love for my children with my love for science. So here we are!
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4 Responses to The fallacy of rare occurrences

  1. Deb says:

    Also, sure, if a person don’t get vaccinated maybe it won’t be bad for *them* — but what about the cancer patient with zero immune system or the infant who hasn’t been vaccinated yet? Vaccinations especially protect those who cannot fight off disease like healthy adults can. If people don’t think *they* would get sick, I sure wish they would think about the others who most certainly will get sick (or worse) as a result of their actions.

    • mamamara says:

      Oh heck yeah. Yael had a classmate a few years ago who probably wasn’t vaccinated because she about a million allergies, and I always think of her when I get my kids vaccinated. She was depending on us to keep her healthy but some people are too selfish.

  2. Jenne says:

    I think the raw milk advocates tend to be kinda nutso, myself, and the supporters of Dan Allyer complete nutcases, but I’ve bought raw milk and would do it again. PA grants a small but significant number of raw milk producers the right to sell raw milk from their own farms, provided there are additional inspections. Since PA food inspections are the national/international standard, I’m not all that worried about it. (Dan Allyer, as I recall, was the guy who was banned from selling raw milk because he refused to go through the raw milk inspection process/get a raw milk permit, then went on selling raw milk. And had the guts to complain that he was being persecuted. Idiot.) As long as people know what they are buying– including the risks– and a high level of sanitation is maintained (shots, testing, specific kinds of water contact forbidden) then I think one could manage a safe, tiny niche for raw milk and raw cheese. On the other hand, I also refused to microwave my lunchmeat when I was pregnant, and I let my kid eat grapes (under supervision).

    There’s got to be a happy medium somewhere, where major food suppliers aren’t spreading salmonella while the food inspectors are out keeping people from selling zucchini bread made in their kitchen. šŸ™‚

    • mamamara says:

      You do have a point that there must be a happy medium somewhere and I’m probably overreacting to the raw milk. I think it’s because I’m reacting to the “OMG you can’t inspect me I’m gonna do what I want blah blah” types.

      I’m just infuriated by people who claim there are no risks to raw milk. Grr.

      Oh, when I was pregnant, I once ate fish that wasn’t cooked all the way through šŸ˜€

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