A Introduction

Can you be biased and still be rational? This may sound like a trick question, and it is. In the preceding chapter, I noted that you can assess whether or not a statement was biased by its justifiability; if you couldn't justify your position according to the known facts, then it would be, by definition, biased.

We all recognize that from another point of view, biased positions are irra­tional; holding them flies in the face of reason. You can't justify them because, well, they're simply wrong. This is the position we're going to examine in this chapter, and you can see right away that we'll have to confront the issue of ration­ality. This issue is what makes the opening question a trick: whether or not bias is rational depends on how you define rationality. This chapter will cover only a few biases rather than a whole catalog of them in order to consider the broader issues of why we have biases and how they affect scientific thinking.

We ordinarily think of rationality as being associated with concepts like “consistent with norms” and “in accordance with reason,” as well as with “logical” and “tending to produce true beliefs.” Indeed, technically speaking, “rationality” has many definitions. Wikipedia notes that “rational” has spe­cialized meanings in philosophy, economics, sociology, psychology, evo­lutionary biology, game theory, and political science.” (And mathematics should have been included.) In this chapter, we'll go into two definitions of rationality in some detail because they directly affect how we think about the scientific hypothesis and the reliability of scientific thinking. One definition is based on logic, in the formal sense of relating to deductive validity that we discussed in earlier chapters, and the other on adaptability to the environ­ment, essentially a pragmatic approach that is related to what works and has worked in the past. An action that is justifiable pragmatically may or may not be formally logical.

12.