160 likes | 286 Views
http://nov15.wordpress.com. LOGICAL REASONING FOR CAT 2009. LOGICAL DEDUCTIONS. Logical Premises. All As are Bs. Premise. Quantifier. Subject. Predicate. Venn Diagrams. All As are Bs. No A is B. B. B. A. A. Venn Diagrams. Some As are Not Bs.
E N D
http://nov15.wordpress.com LOGICAL REASONING FOR CAT 2009
Logical Premises All As are Bs Premise Quantifier Subject Predicate
Venn Diagrams • All As are Bs • No A is B B B A A
Venn Diagrams • Some As are Not Bs • Some As are Bs A B B B A A B A A B A B A B
Rules • The middle term must not appear in the conclusion • All As are Bs • All Bs are Cs • Conclusion cannot contain B Middle Term
Rules • When both premises are affirmative, conclusion cannot be negative • All As are Bs • Some Bs are Cs • Then, conclusion should have only All or Some as the quantifier.
Rules • There must be 3 and only 3 distinct terms • When both premises are particular no conclusion can be derived • Some + some not, some + some, etc… • When both premises are negative, no conclusion can be derived • No + no, no + some not, some not + some not
Rules • The middle term must be distributed at least once. • All As are Bs , Some Bs are Cs • All As are Bs, Some As are Cs
Rules • If one of the premises is particular, then conclusion is particular • Some Bs are Cs • All Cs are Ds • Conclusion has to have quantifier as some.
Rules • When One Quantifier is negative, the conclusion must be negative • No As are Bs • All Bs are Cs • Conclusion must have quantifier as some not or No.
Rules • A term which isn’t distributed in the premise should not be distributed in the conclusion. • All As are Bs • All Bs are Cs --------------------- Middle Term All As are Cs Some A/Cs are C/As
Lets Try an Example You say that sappy movies are always bad? I can prove that isn't true. For instance, Steven Spielberg always makes great movies! But some of his movies are sappy. So, some sappy movies are also great.
Solution • All Steven Speilberg movies are Great • Some Steven Speilberg movies are sappy • Answer is and particular • Some Sappy movies are Great
THANK YOU http://nov15.wordpress.com