Beyond Feelings

76 PART ONE The Context
EXPERT OPINION
As you might expect, expert opinion is generally more reliable than most
of the varieties of evidence we have considered so far. The advantage it
enjoys over personal experience is that it can usually address the crucial
question of what is typical and what is not. Nevertheless, not even expert
opinion is consistently reliable. The most significant reason for unreliability
is that knowledge in virtually every field is rapidly expanding. A century
ago it was possible to gain expertise in more than one discipline.
Today’s scholars typically have expertise in a single narrow aspect of one
discipline and may have difficulty keeping abreast of significant developments
in that one. Unfortunately, some people can’t resist the temptation
to think of themselves as experts in everything. A well-known astronomer,
for example, used to write articles in popular magazines and offer his
opinions on ethics, anthropology, and theology.
To evaluate expert opinion, ask, Does the person have, in addition to credentials
in the broad field in question, specific expertise in the particular
issue under discussion? This is not always easy to ascertain by those outside
the field, but one good indication is that the person does not just
state his or her opinion but also supports it with references to current
research. Also ask whether the expert was paid. The acceptance of money
does not necessarily taint expert opinion, but it may raise questions about
the person’s objectivity. Finally, ask whether other authorities agree or
disagree with the expert’s view.
EXPERIMENT
There are two broad types of experiments. The laboratory experiment enables
researchers to vary the conditions and thereby identify causes and effects
more precisely. One disadvantage of the laboratory experiment, however,
is its artificiality. The field experiment has the advantage of occurring in a
natural setting, but the presence of the researchers can influence the subjects
and distort the findings.
To evaluate experimental evidence, ask, For a laboratory experiment, has
it been replicated by other researchers? For a field experiment, have other
researchers independently confirmed the findings? If replication or confirmation
has been unsuccessfully attempted, it is best to postpone your
acceptance of the experiment’s findings.
STATISTICS
In the broad sense, the term statistics applies to any information that can be
quantified, for example, the changes in average temperature over a period of
time to determine whether the phenomenon of global warming is occurring.