Fallacy of the lonely fact

Imagine an argument that goes like this.

Jane: Australians are thieves.
John: Can you prove that?
Jane: Are you saying that no Australians have ever stolen anything?

Jane has committed the fallacy of the lonely fact. Knowing that at least one Australian has stolen something, she has concluded that all Australians are thieves. The example of the Australians shows that it is an absurd “argument” but it is a favorite of “natural” childbirth advocates and lactivists.

For example:

NCB Advocate: Obstetrics is not evidence based.
Me: Can you prove that?
NCB Advocate: Are you saying that no principle of obstetrics has ever been proven wrong? Look at what happened with episiotomies.


NCB Advocate: C-sections are usually unnecessary.
Me: Can you prove that?
NCB Advocate: Are you saying all C-sections are necessary? I know for a fact that my cousin’s C-section was unnecessary.

Or a slightly different formulation:

Me: The benefits of breastfeeding have been overstated.
Lactivist: So you’re saying that breastfeeding is no better than bottle feeding?

In every case, the reasoning is based on the assumption that a specific example tells us something about the whole. The fact that episiotomies were used even though scientific evidence later showed them to have no benefit is used to justify the assumption that everything in obstetrics is used even though there is no scientific evidence to support it. A single (or a few) unnecessary C-sections are used to justify the assumption that all (or most) C-sections are unnecessary. In the third example, a single criticism of the benefits of breastfeeding is used to justify the assumption that I believe that breast feeding has no benefit at all.

The fallacy of the lonely fact is often used by “natural” childbirth advocates, lactivists, and many proponents of alternative health. It is meant to substitute for a lack of actual evidence. “Natural” childbirth advocates don’t know whether specific obstetric recommendations lack evidence, and they don’t want to bother finding out. They use one example and generalize to everything else. C-section activists don’t know what proportion of C-sections are unnecessary. The fact that some may be unnecessary is enough for them to assume that all (or most) are unnecessary. Lactivists routinely overstate the benefits of breastfeeding, and when question, don’t bother to find out the magnitude of the benefits. They prefer to claim that anyone who questions any benefits questions all benefits and therefore can be dismissed.

The fallacy of the lonely fact is a fallacy because it is based on the assumption that a specific example (episiotomies, for instance) can be generalized to the every possible example (all of obstetrics). Just as the fact that one or even more than one Australian stole something doesn’t make all Australians thieves, a single example can never be assumed to apply universally.