There's an invidious rhetorical strategy that we've all seen — and I'm afraid that most of us have inflicted it on others as well. I call it the Veeck effect (of the first kind) — it occurs whenever someone adjusts the standards of evidence in order to favor a preferred outcome.
Why Veeck? Bill Veeck was a flamboyant baseball owner and promoter.
In his autobiography — (Veeck — As in Wreck) he described installing a flexible fence in the right field of the Milwaukee Brewers. At first he only put the fence up when facing a team full of power hitters, but eventually he took it to the limit, moving the fence up when the visitors were at bat and down when his team was.
The history of science is littered with flexible fences. The phlogiston theory predicted that phlogiston would be released when magnesium burned. It looked bad for that theory when experiments showed that burning magnesium became heavier — but its supporters happily explained that phlogiston had negative weight.
Consider Kepler. He came up with the idea that the distances of the six (known) planets could be explained by nesting the five Platonic solids. It almost worked for Earth, Mars, and Venus, but clearly failed for Jupiter. He dismissed the trouble with Jupiter, saying "nobody will wonder at it, considering the great distance". The theory certainly wouldn't have worked with any extra planets, but fortunately for Kepler's peace of mind, Uranus was discovered well after his death.
The Veeckian urge is strong in every field, but it truly flourishes in the human and historical sciences, where the definitive experiments that would quash such nonsense are often impossible, impractical, or illegal. Nowhere is this tendency stronger than among cultural anthropologists, who at times seem to have no reason for being other than refurbishing the reputations of cannibals.
Sometimes this has meant denying a particular case of cannibalism, for example among the Anasazi in the American Southwest. Evidence there has piled up and up -archaeologists have found piles of human bones with muscles scraped off, split open for marrow, polished by stirring in pots. They have even found human feces with traces of digested human tissue. But that's not good enough. For one thing, this implication of ancient cannibalism among the Anasazi is offensive to their Pueblo descendants, and that somehow trumps mounds of bloody evidence. You would think that the same principle would cause cultural anthropologists to embrace the face-saving falsehoods of other ethnic groups - didn't the South really secede over the tariff? But that doesn't seem to happen.
Some anthropologists have carried the effort further, denying that any culture was ever cannibalistic. They don't just deny Anasazi archaeology — they deny every kind of evidence, from archaeology to historical accounts, even reports from people alive today. When Álvaro de Mendaña discovered the Solomon Islands, he reported that a friendly chieftain threw a feast and offered him a quarter of a boy. Made up, surely. The conquistadors described the Aztecs as a cannibal kingdom — can't be right, even if the archeology supports it. When Papuans in Port Moresby volunteered to have a picnic in the morgue — to attract tourists, of course — they were just showing public spirit.
The Quaternary mass extinction, which wiped out much of the world's megafauna, offers paleontologists a chance to crank up their own fences. The large marsupials, flightless birds and reptiles of Australia disappeared shortly after humans arrived, about 50,000 years ago. The large mammals of North and South America disappeared about 10,000 years ago — again, just after humans showed up. Moas disappear within two centuries after Polynesian colonization in New Zealand, while giant flightless birds and lemurs disappeared from Madagascar shortly after humans arrived. What does this pattern suggest as the cause? Why, climate change, of course. Couldn't be human hunters — that's unpossible!
The Veeck effect is even more common in everyday life than it is in science. It's just that we expect more from scientists. But scientific examples are clear-cut, easy to see, and understanding the strategy helps you avoid succumbing to it.
Whenever some Administration official says that absence of evidence is not evidence of absence — whenever a psychiatrist argues that Freudian psychotherapy works for some people, even if proven useless on average — Bill Veeck's spirit goes marching on.
*If you're wondering about the second Veeck effect, it's the intellectual equivalent of putting a midget up to bat. And that's another essay.