R——>~T
~R
Therefore, T
[Note: Two negatives make a positive, so the conclusion ~(~T) was reduced to
T.] This diagram clearly shows that the argument is committing the fallacy
of denying the premise. An if-then statement is made; its premise is negated
; then its conclusion is negated.
Transitive Property
A——>B
B——>C
Therefore, A——>C
These arguments are rarely difficult, provided you step back and take a bir
d's-eye view. It may be helpful to view this structure as an inequality in m
athematics. For example, 5 > 4 and 4 > 3, so 5 > 3.
Notice that the conclusion in the transitive property is also an if-then sta
tement. So we don't know that C is true unless we know that A is true. Howev
er, if we add the premise “A is true” to the diagram, then we can conclude t
hat C is true:
A——>B
B——>C
A
Therefore, C
As you may have anticipated, the contrapositive can be generalized to the tr
ansitive property:
A——>B
B——>C
~C
Therefore, ~A
Example: (Transitive Property)
If you work hard, you will be successful in America. If you are successful i
n America, you can lead a life of leisure. So if you work hard in America, y
ou can live a life of leisure.