Take-aways from *Bias: A Philosophical Study*

1. Bias defined. In one case, a bad thermometer errs in both directions: sometimes reading too high (say, 74 when the temp is 72), sometimes too low. In another, the errors are not random, but systematic—it tends, say, to read too high. In the second case, the thermometer is not just unreliable; it is biased. In this book Thomas Kelly defends a definition of bias that fits this case:

Bias is the systematic deviation from a norm, or standard of correctness.

For the thermometer, the norm is accuracy: getting the temperature right. Other norms abound, and so therefore do other kinds of bias. Judges, for example, are subject to the norm proportion the punishment to the crime. A judge, therefore, whose sentencing is more lenient in the afternoon than in the morning, or while full than while hungry, is biased.

While some philosophers earn fame and glory for defending crazy and obviously false ideas, this theory of bias seems right at first glance: a more precise articulation of what everyone already hazily believes. Kelly agrees, but warns that it has “far-reaching and radical implications.”

2. The limits of charity. You’re reasonable and open-minded, of course. But also opinionated: your political beliefs fall somewhere on the “Left-Right” spectrum:

Mine do too; let us suppose, somewhat to the Right of yours:

While you disagree with me, and so (necessarily) think I am wrong, you don’t think I’m stupid, idiotic, or even irrational. Reasonable people can disagree!

You may want also to think that I am unbiased. It would be mean to think otherwise, right? But, Kelly argues, to be that open-minded, would be irrational.

From your perspective, you view is true: