To avoid the various foolish opinions to which mankind are 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(31)______， by the simple device of asking Mrs. Aristotle to keep her mouth open while he counted． I believe myself that hedgehogs eat black beetles，because(32) ______； but if I were writing a book on the habits of hedgehogs，I should not commit myself until(33) ______． Aristotle，however, was less cautious．Ancient and medieval authors knew all about unicorns and salamanders；not one of them thought it necessary to avoid dogmatic statements about them because(34) ______.

Many matters，however, are less easily brought to the test of experience．If, like most of mankind，(35) ______ 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(36) ______．If some one maintains that two and two are five，or that Iceland is on the equator, you feel pity rather than anger, unless (37) ______ that his opinion shakes your own contrary conviction．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 (38) ______, but in theology there is only opinion．So whenever you find yourself getting angry about a difference of opinion，(39) ______； you will probably find，on examination，that (40) ______．It is a good way of riding yourself of certain kinds of biased opinions to become aware of those different from your own．

(From How to Avoid the Foolish Opinions)

[A] I have been told that they do

[B] be on your guard

[C] he had never seen one of them

[D] I had seen one enjoying this unappetizing diet

[E] you are subconsciously aware of having no good reason for thinking as you do

[F] man is a brief episode in the life of a small planet in a little comer of the universe

[G] you know so little of arithmetic or geography

[H] the question is one to which there is no demonstrably right answer

[I] women have fewer teeth than men

[J] your belief is going beyond what the evidence warrants

[K] in arithmetic there is knowledge

[L] you have passionate convictions on many such matters

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