Beyond Feelings

CHAPTER 6 What Is Evidence?
respects. Here is an actual example of an issue that has been badly confused
by the use of irrelevant evidence. For years, many college administrators
rejected instructors’ requests for a reduction in class size for
courses such as writing, speaking, and critical thinking. The administrators
cited scholarly studies demonstrating that teaching effectiveness is
unrelated to class size—in other words, that teachers can be as effective
with fifty students in the classroom as they are with fifteen. Yet the scholarly
studies in question examined only courses that impart information,
not those that develop skills. For the latter, the very courses in question,
the evidence had no relevance.
Evaluating Evidence
We all like to think of ourselves as totally objective, equally open to either
side of every issue. But that is rarely the case. Even if we have not yet
taken a firm position on an issue at the outset of our evaluation, we will
usually be tilted in one direction or the other by our overall philosophy of
life, our political or social views, our opinions on related issues, or our attitude
toward the people associated with the various views. This tilting,
also known as bias, may be so slight that it has little or no effect on our
judgment. On the other hand, it may be significant enough to short-circuit
critical thinking. The more we tilt on an issue, the greater our thinking
deficit is likely to be.
How can you tell when bias is hindering your evaluation of evidence?
Look for one or more of these signs:
• You approach your evaluation wanting one side to be proved right.
• You begin your investigation assuming that familiar views will
prove correct.
• You look for evidence that supports the side of the issue you favor
and ignore evidence that opposes it.
• You rate sources by how favorable they are to your thinking rather
than by their reliability and the quality of their research.
• You are nitpickingly critical of evidence for views you oppose and
uncritical of evidence for views you favor.
• When you encounter evidence that opposes your bias, you begin
arguing against it, often before you have completed examining it.
Although you may not be able to eliminate your biases, you can
nevertheless identify and control them, and that is all that is necessary.
The purpose of evaluating evidence is to discover the truth, regardless
of whether it is pleasant or unpleasant, and the only way to do so is to
evaluate fairly. Such an evaluation will sometimes require you to conclude
that the view you leaned toward (or actually held) is mistaken.
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