How to Avoid Foolish Opinions

To avoid the various foolish opinions to which mankind is prone,
no superhuman genius is required.
A few simple rules will keep you,
not from all error,
but from silly error.
If the matter is one that can be settled by observation,
make the observation yourself.
Aristotle could have avoided the mistake of thinking
that women have fewer teeth than men,
by the simple device of asking Mrs. Aristotle
to keep her mouth open while he counted.
He did not do so because he thought he knew.
Thinking that you know
when in fact you don’t is a fatal mistake,
to which we are all prone.
Many matters, however,
are less easily brought to the test of experience.
If, like most of mankind,
you have convictions on many such matters,
there are ways in which
you can make yourself aware of your own bias.
If an opinion contrary to your own makes you angry,
that is a sign that you are subconsciously aware
of having no good reason for thinking as you do.
If someone maintains that two and two are five,
you feel pity rather than anger.
The most savage controversies are those about matters
as to which there is no good evidence either way.
Persecution is used in theology, not in arithmetic,
because in arithmetic there is knowledge,
but in theology there is only opinion.
So whenever you find yourself getting angry
about a difference of opinion,
be on your guard; you will probably find,
on examination,
that your belief is going beyond what the evidence warrants.
A good way of riding yourself of certain kinds of dogmatism
is to become aware of opinions held in social circles different from your own.
Seek out people with whom you disagree,
and read a newspaper belonging to a party that is not yours.
If the people and the newspaper seem mad and wicked,
remind yourself that you seem so to them.
In this opinion both parties may be right,
but they cannot both be wrong.
This reflection should generate caution.