Beyond Feelings

CHAPTER 6 What Is Evidence?
We can all identify with those people. More often than most of us
would care to admit, when called on to support our opinions, we manage
to produce only the flimsiest of evidence. We may soothe ourselves with
the notion that a thick folder of evidence lies misfiled in our minds, but the
very real possibility remains that flimsy evidence was all we ever had.
Critical thinkers are tempted to commit the same self-deception that
plagues others, but they have learned the value of resisting that temptation.
More important, they have developed the habit of checking the quality
and quantity of the evidence before forming an opinion. Also, they
review their evidence before expressing an opinion. The extra time this
takes is more than compensated for by the confidence that comes from
knowing what they are talking about.
Kinds of Evidence
To evaluate your own and other people’s opinions, you will need to understand
the various kinds of evidence. This entails knowing the value
and limitations of each kind, as well as the appropriate questions to ask.
The most important kinds of evidence are personal experience, unpublished
report, published report, eyewitness testimony, celebrity testimony, expert opinion,
experiment, statistics, survey, formal observation, and research review.
It is important to note that the arrangement here is not in ascending or
descending order of reliability but rather in rough order of familiarity—
with personal experience being very familiar to most people and research
review much less familiar.
PERSONAL EXPERIENCE
Personal experience is the one kind of evidence we don’t have to go to the
library or the Internet to get. We carry it with us in our minds. For this reason,
it tends to exert a greater influence than other kinds of evidence. The
individuals we’ve met, the situations we’ve been in, and the things that
have happened to us seem more authentic and meaningful than what we
have merely heard or read. We are confident about our personal experience.
Unfortunately, this confidence can cause us to attach greater significance
and universality to particular events than they deserve. If we ride in
a New York City taxicab on one occasion, we may think we are acquainted
with New York City taxicab drivers. If we have a Korean friend, we may
feel that we know Koreans in general or even Asians in general. However,
it takes more than one or a few examples to support a generalization; for
sweeping generalizations, even a dozen may not be enough.
To evaluate personal experience—your own or other people’s—ask, Are the
events typical or unique? Are they sufficient in number and kind to support
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