Fascinating Mangling of Falsification revisited

By Brian Clegg

REVISIT SERIESAn updated post from January 2016

I have just read an article (don’t ask me why – this is the wonder of Facebook) which tried to separate the value of Mormonism from the worrying details of its origins. The piece [linked in the original but no longer available] included this:

Many intellectuals argue that “negative evidence” is supreme. To understand what they mean by this, consider the hypothesis that “all swans are white.” According to these intellectuals, it doesn’t matter how many white swans you find, you never really prove that “all” swans are white. However, as soon as you find one black swan, you have disproved the theory that “all swans are white.” They conclude that positive evidence doesn’t ever really prove anything, but negative evidence can. And it’s easy to see why they think that way. 

This is the approach that ex-Mormons have taken to their faith. In the face of unsettling information, they disregard all of the positive evidence because they think that a few points of negative evidence is sufficient to end the discussion. And given how logical the above reasoning seems to be, it is no wonder why. But they are still wrong. 

To understand why, consider another example. After first discovering the planet Uranus, astronomers attempted to predict its orbit by using Sir Isaac Newton’s laws of physics. They could observe the orbit of Uranus with their own eyes, but when they used Newton’s mathematical models to predict that orbit, they failed time and again. It made no sense. Newton’s laws had been right about so many things, but astronomers had found a case in which Newton’s laws did not work. So, was Newton wrong? Were his laws not quite as infallible as they had seemed? In light of this “negative evidence,” it would have been easy to conclude just that. 

However, years later, astronomers discovered another planet, Neptune. And as it turns out, when astronomers accounted for the mass of this newly discovered planet, Newton’s laws predicted the orbit of Uranus perfectly. So, as it turned out, it wasn’t that Newton’s laws of physics didn’t work. It was that they didn’t seem to work. And that’s because the astronomers simply didn’t have all the relevant information and context.

There’s so much to get your teeth into here, but we’ll pick out two key points. First there’s the ad hominem attack. ‘Many intellectuals argue… According to these intellectuals… and it’s easy to see why they think this way.’ Implication: intellectuals don’t know what they are talking about. Don’t listen to them. Note particularly ‘According to these intellectuals, it doesn’t matter how many white swans you find.’ Forget ‘According to intellectuals.’ It’s just true. It doesn’t matter how many white swans you find. All swans are not white. Are they arguing otherwise? Check out the photo.

However, no one suggests that falsification is usefully applicable to everything. Which is why it’s odd that they then give an example where it isn’t properly used. All scientific evidence is provisional. The black swan disproves the ‘all swans are white’ hypothesis, and that is the best data at the time and the only sensible viewpoint. But should it later prove that the ‘black swan’ was an unusual variant of the goose family and not a swan at all, the hypothesis could recover. However, the Newton example used in the extract from the article above fails on a number of counts.

First, the orbit of Uranus didn’t show that ‘Newton’s laws of physics don’t work’ it showed that they didn’t apply in that circumstance. There are plenty of other examples (Mercury’s orbit, for instance) where they will never apply. As it happened, in the case of Uranus, it was because the astronomers didn’t take into account the full situation. But there was nothing wrong with the assertion that Newton’s law of gravitation didn’t correctly describe the orbit of Uranus in the known solar system of the time. And until other factors were brought in, one possibility was that this was a case (as is true of the orbit of Mercury) where Newton’s law wasn’t appropriate.

This argument is then used to suggest that yes, there are worrying aspects of the early history of Mormonism that cast its basis into doubt. Until you can show why that negative evidence is misleading – and that isn’t happening – you can have all the positive evidence you like (which is what, exactly?) and the negative evidence still stands. Even in the Uranus example, the results showed their was something wrong with the astronomers’ assumptions. Falsification remains a powerful tool, and a valuable one in cases like this.

Image from Unsplash by Kirtesh Mahant – I know it’s not Poldark, but same kind of thing.

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Now Appearing is the blog of science writer Brian Clegg (www.brianclegg.net), author of Inflight Science, Before the Big Bang and The God Effect.