We often feel that an argument should be doubted or held as suspicious because it has a bias. But bias isnt always wrong. It is a normal phenomenon in advocacy argumentation, and in many cases it is to be expected. Yet sometimes bias can be quite harmful in argumentation. In this book, bias is defined as one-sided advocacy of a point of view in argumentation. It is shown to be harmful, or properly subject to critical condemnation, only when the dialogue exchange is supposed to be a balanced, two-sided exchange of viewpoints.

The book concedes the postmodernist premise that bias is quite normal in everyday conversational arguments, and that a finding of bias should not, by itself, constitute grounds for criticizing an argument as critically deficient or fallacious. But the book strongly disagrees with the postmodernist conclusion that no standard of rationality can be brought to bear to condemn narrowly interest-based or one-sided arguments as biased. It is argued that in some cases narrow, one-sided partisanship in an argument is justifiably a basis for negative criticism of the worth of the argument.