1. SHORTER TRUTH TABLE METHOD OR REDUCTIO-AD-ABSURDUM
A PRESENTATION BY
DR. BUDUL CHANDRA DAS.
ASSISTANT PROFESSOR OF PHILOSOPHY
WOMEN’S COLLEGE, TINSUKIA
TINSUKIA –
ASSAM

2. SHORTER TRUTH TABLE METHOD OR REDUCTIO-AD-ABSURDUM
LET US CONSIDER THE FOLLOWING ARGUMENT- FORM:
p q
q r
Therefore, p r ∩ ∩ ∩
-This argument may be converted to a truth functional expression as:
(p q) . (q r) } (p r) ∩ ∩ ∩ ∩
THERE
ARISES A
CONTRADICTION
NOW LOOK AT
THE GREEN OVAL FUNCTION T T T F F T T T T F F
NOW, AN
IMPLICATIVE FUNCTION BECOMES FALSE WHEN THE
ANTECEDENT IS TRUE AND THE
CONSEQUENCE IS FALSE. THUS…
NOW, A CONJUNCTIVE FUNCTION WILL BE TRUE IF BOTH THE CONJUNCTS ARE TRUE.
THUS THE VALUES FOR BOTH THE IMPLICATIVE FUNCTIONS OF THE FIRST PART WILL BE
TRUE. i.e.
ANTECEDENT
CONSEQUENT
MAIN CONSTANT
THIS CONTRADICTION MEANS OUR ORIGINAL ASSUMPTION IS WRONG,SO THE ARGUMENT IS VALID.
CONSIDER IT AS FALSE & PUT A F FOR THIS CONSTANT
THEN FOLLOWING THE SAME METHOD IN CACE OF THE VARIABLES
WE HAVE AS SHOWN…

3. Thank You