Truth Tables

The topic I found interesting about the truth tables was checking for validity. (pg.368)

An agrument form is valid if every argument of the form is valid. We can show that an argument is valid by making a table that includes all the premises and the conclusion. If in every row in which all the premises are true, too, then the form is valid.


This was a little bit complicated for me to understand in the begining but this website had some hand on examples http://people.hofstra.edu/Stefan_Waner/RealWorld/logic/logic6.html


Checking for Validity using Truth-Tables:
Now we can give a mechanical method for checking many arguments for validity using truth-tables.
An argument is TT-valid if and only if there is no substitution of truth values for atomic sentences in the argument that makes all the premises true and the conclusion false. Examples:


A B | A or B | not B | A
-------------------------
T T | T | F | T
T F | T | T | T
F T | T | F | F
F F | F | T | F

There is no row on which all the premises are true and the conclusion false, therefore the above argument is valid.

http://www.ocf.berkeley.edu/~brianwc/courses/thinking/logicalform.html