58 Anecdotal Evidence p4 (Atheism - Constructing a Logical Argument)
Description
This article is from the Atheism FAQ, by mathew meta@pobox.com with numerous contributions by others.
58 Anecdotal Evidence p4 (Atheism - Constructing a Logical Argument)
Complex question / Fallacy of interrogation / Fallacy of presupposition
This is the interrogative form of Begging the Question. One example is
the classic loaded question:
"Have you stopped beating your wife?"
The question presupposes a definite answer to another question which
has not even been asked. This trick is often used by lawyers in
cross-examination, when they ask questions like:
"Where did you hide the money you stole?"
Similarly, politicians often ask loaded questions such as:
"How long will this EU interference in our affairs be allowed to
continue?"
or
"Does the Chancellor plan two more years of ruinous privatization?"
Another form of this fallacy is to ask for an explanation of something
which is untrue or not yet established.
Ignoratio elenchi / Irrelevant conclusion
The fallacy of Irrelevant Conclusion consists of claiming that an
argument supports a particular conclusion when it is actually
logically nothing to do with that conclusion.
For example, a Christian may begin by saying that he will argue that
the teachings of Christianity are undoubtably true. If he then argues
at length that Christianity is of great help to many people, no matter
how well he argues he will not have shown that Christian teachings are
true.
Sadly, such fallacious arguments are often successful because they
arouse emotions which cause others to view the supposed conclusion in
a more favourable light.
Equivocation / Fallacy of four terms
Equivocation occurs when a key word is used with two or more different
meanings in the same argument. For example:
"What could be more affordable than free software? But to make sure
that it remains free, that users can do what they like with it, we
must place a license on it to make sure that will always be freely
redistributable."
One way to avoid this fallacy is to choose your terminology carefully
before beginning the argument, and avoid words like "free" which have
many meanings.
Amphiboly
Amphiboly occurs when the premises used in an argument are ambiguous
because of careless or ungrammatical phrasing.
Accent
Accent is another form of fallacy through shifting meaning. In this
case, the meaning is changed by altering which parts of a statement
are emphasized. For example, consider:
"We should not speak *ill* of our friends"
and
"We should not speak ill of our *friends*"
Be particularly wary of this fallacy on the net, where it's easy to
mis-read the emphasis of what's written.
Fallacies of composition
One Fallacy of Composition is to conclude that a property shared by
the parts of something must apply to the whole. For example:
"The bicycle is made entirely of low mass components, and is
therefore very lightweight."
The other Fallacy of Composition is to conclude that a property of a
number of individual items is shared by a collection of those items.
For example:
"A car uses less petrol and causes less pollution than a bus.
Therefore cars are less environmentally damaging than buses."
Fallacy of division
The fallacy of division is the opposite of the Fallacy of Composition.
Like its opposite, it exists in two varieties. The first is to assume
that a property of some thing must apply to its parts. For example:
"You are studying at a rich college. Therefore you must be rich."
The other is to assume that a property of a collection of items is
shared by each item. For example:
"Ants can destroy a tree. Therefore this ant can destroy a tree."
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