We should all be biased

In #articles

A friend and colleague of mine said to me recently that she was nervous that she might become "biased against any new health invention/method/etc... because virtually all of them have been ridiculous". This is a feeling I've had from time to time, and I've heard it leveled against skeptics from the proponents of these new methods.

I think, however, given the (lack of) performance of the bulk of these claims, ones prior probability - quite rationally - should be low for the next one. It's not a bias to recognize that, all things being equal, the next silver bullet health claim is likely to be false. It should, however, be very easy for a health treatment that actually works to redeem itself above this prior probability. The criticism of "bias" is raised only when the treatment hasn't actually been demonstrated.

The term bias is tricky depending on its usage. In many ways, bias is perfectly rational, if it means assuming something is false before the evidence. Does one say that a jury is biased against the guilt of the suspect? I think this sentence points to the fact that the word "bias" is typically used in a pejorative fashion, synonymous with being resistant to evidence. Even here, resistant to evidence is rational to the extent that stronger evidence is needed to raise a lower prior probability.

Perhaps "bias" should mean willing to ignore some of the evidence against ones present view, in order to maintain this view. This can come innocently in the form of confirmation bias, and not be a deliberate distortion. Clearly this violates the axioms of probability, and should be avoided. Proper scientific thinking and process is constructed specifically to avoid this sort of bias, while at the same time supporting the rational forms of bias.