I used to tell my students that science was the search for truth, not Truth.

Truth, the one with a capital-T, is the bailiwick of philosophers, theologians, and mystics.

I think what I really meant by lower-case-t truth was things that are true. Things that are true are things that work regardless of your belief system. If we drop you on your head from a height there will be a poor outcome for you. That’s one of those true things. People could still argue the point of course. But when the time comes to test things out they won’t be found.

It’s really hard to sort out true things. Think about how hard it is to sort out medical claims. I know we’ve all done research on the internet about some health topic. Right away we find too many sites, too many papers, too many competing claims, and too many voices screaming for our attention.

So, what to do?

I found a bit of good advice from John Mandrola (via Andrew Gelman).

The most important priors when it comes to medical claims are simple: most things don’t work. Most simple answer answers are wrong. Humans are complex. Diseases are complex. Single causes of complex diseases like cancer should be approached with great skepticism.

In statistics a “prior” is a probability distribution that you assume to be true before collecting any evidence. That’s fine for scientists, but for the rest of us we can just say that a “prior” is stuff we already know.

Most things don’t work is an excellent rule-of-thumb. It’s tough to follow because we really really really want some things to be true. And it’s hard to let go of biases. Being a skeptic does not mean being a cynic, but it does mean, in Mandrola’s words, that you should “hold pessimistic priors.” He also says “know that stuff that really works is usually obvious.”

In the end, it’s all about accepting uncertainty. The big, important questions have fuzzy answers. Life is not a multiple choice test—it’s closer to an endless series of essays! Since there’s no one correcting your grammar or giving you a grade all we have to produce are rough drafts. Pencils and erasers are allowed and cross-outs are encouraged. And there’s plenty of fresh paper when you run out.