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[TUTORIAL F02] Inconsistency
Fallacies of inconsistency are cases where something
inconsistent, self-contradictory orself-defeating is presented.
F02.1 Inconsistency
Here are some examples:
"One thing that we know for certain is that nothing is ever true
or false." - If there issomething we know for certain, then there
is at least one truth that we know. So it can'tbe the case that
nothing is true or false."Morality is relative and it is just a
matter of opinion, and so it is always wrong toimpose our opinions
on other people." - But if morality is relative, it is also a
relativematter whether we should impose our opinions on other
people. If we should not dothat, there is at least one thing that
is objectively wrong."All general claims have exceptions." - This
claim itself is a general claim, and so if itis true, it must also
have an exception itself. This implies that not all general
claimshave exceptions. So the claim itself is inconsistent.
F02.2 Self-defeating claims
A self-defeating statement is a statement that strictly speaking
is not logically inconsistent,but is near enough in that it is
obviously false when being asserted. Consider theseexamples:
Very young children are fond of saying "I am not here" when they
are playing hide-and-seek. The statement itself is not logically
inconsistent, since it is logically possible for
the child not to be where she is. What is impossible is to utter
the sentence as a true
sentence (unless it is used for example in a telephone recorded
message.)Someone who says, "I cannot speak any English."Here is an
actual example. A TV programme in Hong Kong was critical of
theGovernment. When the Hong Kong Chief Executive Mr. Tung was
asked about it, hereplied , "I shall not comment on such
distasteful programs." Mr. Tung's remark wasnot logically
inconsistent, because what it describes is a possible state of
affairs. But itis nonetheless self-defeating because calling the
program "distasteful" is to pass acomment!
