vagrant

From Stephen's Guide (11)
Fallacies of Ambiguity

--------------------------------------------------------------------------------

The fallacies in this section are all cases where a word or phrase is used unclearly.
There are two ways in which this can occur.


(i) The word or phrase may be ambiguous, in which case it has more than
one distinct meaning.

(ii) The word or phrase may be vague, in which case it has no distinct
meaning.

The following are fallacies of ambiguity:

1. Equivocation

--------------------------------------------------------------------------------
Definition:
The same word is used with two different meanings.

Examples:
(i) Criminal actions are illegal, and all murder trials are
criminal actions, thus all murder trials are illegal. (Here the
term "criminal actions" is used with two different meanings.
Example borrowed from Copi.)
(ii) The sign said "fine for parking here", and since it was
fine, I parked there.
(iii) All child-murderers are inhuman, thus, no child-
murderer is human. (From Barker, p. 164; this is called
"illicit obversion")
(iv) A plane is a carpenter's tool, and the Boeing 737 is a
plane, hence the Boeing 737 is a carpenter's tool. (Example
borrowed from Davis, p. 58)

Proof:
Identify the word which is used twice, then show that a
definition which is appropriate for one use of the word would
not be appropriate for the second use

2.Amphiboly

--------------------------------------------------------------------------------

Definition:

An amphiboly occurs when the construction of a sentence
allows it to have two different meanings.

Examples:
(i) Last night I shot a burglar in my pyjamas.
(ii) The Oracle of Delphi told Croseus that if he pursued the
war he would destroy a mighty kingdom. (What the Oracle
did not mention was that the kingdom he destroyed would
be his own. Adapted from Heroditus, The Histories.)
(iii) Save soap and waste paper. (From Copi, p. 115)

Proof:
Identify the ambiguous phrase and show the two possible
interpretations.

3. Accent

--------------------------------------------------------------------------------

Definition:

Emphasis is used to suggest a meaning different from the
actual content of the proposition.

Examples:
(i) It would be illegal to give away
Free Beer!
(ii) The first mate, seeking revenge on the captain, wrote in
his journal, "The Captain was sober today." (He suggests, by
his emphasis, that the Captain is usually drunk. From Copi,
p. 117)

vagrant

From Stephen's Guide (12)
Category Errors

--------------------------------------------------------------------------------

These fallacies occur because the author mistakenly assumes that the whole is
nothing more than the sum of its parts. However, things joined together may have
different properties as a whole than any of them do separately.
The following fallacies are category errors:

1. Composition

--------------------------------------------------------------------------------

Definition

Because the parts of a whole have a certain property, it is argued
that the whole has that property. That whole may be either an object
composed of different parts, or it may be a collection or set of
individual members.

Examples:
(i) The brick wall is six feet tall. Thus, the bricks in the wall are six
feet tall.
(ii) Germany is a militant country. Thus, each German is militant.
(iii) Conventional bombs did more damage in W.W. II than nuclear
bombs. Thus, a conventional bomb is more dangerous than a
nuclear bomb. (From Copi, p. 118)


Proof:
Show that the properties in question are the properties of the whole,
and not of each part or member or the whole. If necessary, describe
the parts to show that they could not have the properties of the
whole.

2. Division

--------------------------------------------------------------------------------

Definition:

Because the whole has a certain property, it is argued that the parts
have that property. The whole in question may be either a whole
object or a collection or set of individual members.

Examples:
(i) Each brick is three inches high, thus, the brick wall is three
inches high.
(ii) Because the brain is capable of consciousness, each neural cell
in the brain must be capable of consciousness.

Proof:
Show that the properties in question are the properties of the parts,
and not of the whole. If necessary, describe the parts to show that
they could not have the properties of the whole.

vagrant

From Stephen's Guide (13)
Non-Sequitur

--------------------------------------------------------------------------------

The term non sequitur literally means "it does not follow". In this section we
describe fallacies which occur as a consequence of invalid arguments.
The following fallacies are non sequiturs:

1. Affirming the Consequent

--------------------------------------------------------------------------------

Definition:

Any argument of the following form is invalid:
If A then B
B
Therefore, A

Examples:
(i) If I am in Calgary, then I am in Alberta. I am in Alberta,
thus, I am in Calgary. (Of course, even though the premises
are true, I might be in Edmonton, Alberta.)
(ii) If the mill were polluting the river then we would see an
increase in fish deaths. And fish deaths have increased. Thus,
the mill is polluting the river.

Proof:
Show that even though the premises are true, the conclusion
could be false. In general, show that B might be a
consequence of something other than A. For example, the fish
deaths might be caused by pesticide run-off, and not the mill

2. Denying the Antecedent

--------------------------------------------------------------------------------

Definition:

Any argument of the following form is invalid:
If A then B
Not A
Therefore, Not B

Examples:
(i) If you get hit by a car when you are six then you will die
young. But you were not hit by a car when you were six.
Thus you will not die young. (Of course, you could be hit by
a train at age seven, in which case you still die young.)
(ii) If I am in Calgary then I am in Alberta. I am not in
Calgary, thus, I am not in Alberta.

Proof:
Show that even though the premises are true, the conclusion
may be false. In particular, show that the consequence B may
occur even though A does not occur.

3. Inconsistency

--------------------------------------------------------------------------------

Definition:

The author asserts more than one proposition such that the
propositions cannot all be true. In such a case, the
propositions may be contradictories or they may be
contraries.

Examples:
(i) Montreal is about 200 km from Ottawa, while Toronto is
400 km from Ottawa. Toronto is closer to Ottawa than
Montreal.
(ii) John is taller than Jake, and Jake is taller than Fred,
while Fred is taller than John.

Proof:
Assume that one of the statements is true, and then use it as
a premise to show that one of the other statements is false

baby11

thanks, though in English

applebees

thanks1