When we form a proposition or belief we generalize from what
is observed – our own analysis or experience – and thence infer
to what is not observed. We also refer to testimony – other
people’s observations and experience.
If your proposition or belief is derived from a generalization
based upon particular instances you should test it by answering
the following questions:
■ Was the scope of the investigation sufficiently comprehen-
sive?
■ Are the instances representative or are they selected to
support a point of view?
■ Are there contradictory instances that have not been looked
for?
■ Does the proposition or belief in question conflict with other
beliefs for which we have equally good grounds?
■ If there are any conflicting beliefs or contradictory items of
evidence, have they been put to the test against the original
proposition?
■ Could the evidence or testimony lead to other equally valid
conclusions?
■ Are there any other factors which have not been taken into
account which may have influenced the evidence and, there-
fore, the conclusion?
If your belief is based on testimony, you should test the reliability
of the testimony, its relevance to the point, and whether or not
your belief follows logically from the evidence, ie can reasonably
be inferred from the facts.
FALLACIOUS AND MISLEADING
ARGUMENTSA fallacy is an unsound form of argument leading to a mistake in
reasoning or a misleading impression. The main fallacies to
avoid or to spot in other people’s arguments are:
■ sweeping statements;
■ potted thinking;
■ special pleading;
■ over-simplification;
How to Think Clearly 295