Somebody could give me this glass of water and tell me that it’s water. But there’s a lot of clear liquids out there and I might actually have a real case that this might not be water. Now most cases when something like a liquid is in a cup it’s water.

A good way to find out if it’s water is to test if it has two hydrogens per oxygen in each molecule in the glass and you can test that. If it evaporates like water, if it tastes like water, freezes like water… the more tests we apply, the more sure we can be that it’s water.

However, if it were some kind of acid and we started to test and we found that the hydrogen count is off, the oxygen count is off, it doesn’t taste like water, it doesn’t behave like water, it doesn’t freeze like water, it just looks like water. If we start to do these tests, the more we will know the true nature of the liquid in this glass. That is how we find truth. We can test it any number of ways; the more we test it, the more we know the truth of what it is that we’re dealing with.

• An ex-Mormon implicitly describing Bayesian updates