The following things are demonstrably true:

1. Evolution through natural selection is a scientific fact.
2. Approximately six million European Jews were killed during the Second World War.
3. Between 1969 and 1972, 12 American astronauts walked on the Moon.
4. Everyone should get their child vaccinated; vaccines save countless lives.
5. Human activity is raising the temperature of the planet.

That some people refuse to believe these demonstrably true things is both sad and frustrating. Sometimes it’s because they’ve been convinced by people whose interests are served by replacing a truth with a lie (promoting religious doctrine or a quack cure for autism, economic self-interest, rehabilitating Nazism), but sometimes nutbaggery has no agenda.

Either way, the end result is considerable effort spent defending, proving and reproving what is demonstrably true. What a waste.

A worthy contribution to the fight against the anti-vaccination nutters comes, as many worthy things often do, from Jim Macdonald at Making Light, who points out that the diseases we vaccinate our children against used to kill them in great numbers. (Yes, even measles.) That these diseases don’t any more is because we vaccinate our children.

As a historian, I am often struck by how often people forget why things are the way they are today. It’s easy to fulminate against a social safety net when you’ve never lived without one, for example, but the Great Depression, when unemployment meant utter destitution, meant you had nothing, started only 80 years ago. (Fun fact: government social programs were often enacted not by liberal governments who thought that the poor should be bribed with taxpayers’ money but by conservative governments who hoped to stave off a Communist uprising from a starving and desperate population.)

Still, anyone over the age of 50 will remember what it was like to grow up with the risk of getting polio. That’s not that long ago. There are still people living in iron lungs, for crying out loud.

That people honestly believe that getting vaccinated is a greater risk than not getting vaccinated is — well, I can’t believe people forget so soon.

(For more words in support of vaccination, don’t miss Bad Astronomer Phil Plait’s posts found in his antiscience category.)