Deduction
Inference by Hypothetical Proposition
Name | Rule |
Modus Ponens | p > q, p; therefore q |
Modus Tollens | p > q, -q; therefore -p |
Chain | p > q, q > r; therefore p > r |
Disjunctive1 | p v q, p; therefore -q |
Disjunctive2 | p v q, q; therefore -p |
Addition1 | p; therefore p v q |
Addition2 | q; therefore p v q |
Conjunctive1 | -(p & q), p; therefore -q |
Conjunctive2 | -(p & q), q; therefore -p |
Simplification1 | (p & q); therefore p |
Simplification2 | (p & q); therefore q |
Adjunction | p, q; therefore p & q |
Reductio1 | p > -p; therefore -p |
Reductio2 | p > (q & -q); therefore -p |
Complex constructive | p > q, r > s, p v r; therefore q v s |
Complex destructive | p > q, r > s, -q v -s; therefore -p v -r |
Simple constructive | p > q, r > q, p v r; therefore q |
Simple destructive | p > q, p > r, -q v -r; therefore -p |
Applied Categorical Dilemma rules
• Jane is a Human. Humans are male or female, then remember Jane is male or female.
• if Jane is male and Jane is male or female then forget Jane is male or female.
• if Jane is female and Jane is male or female then forget Jane is male or female.
• if Jane is not male and Jane is male or female then remember Jane is female and forget Jane is male or female and forget Jane is not male.
• if Jane is not female and Jane is male or female then remember Jane is male and forget Jane is male or female and forget Jane is not female.
Creating and resolving a dilemma or disjunction is the other side of the opposition situation. The question is, do we report or respond to the discovery of the dilemma or just remember it until more information is provided to resolve the issue? Here are some possible conversations. T is the tester and R is the responder.
Test 1: report dilemma
Given: humans are male or female.
T: Jane is human.
R: Jane is male or female.
Test 2: ask for resolution of dilemma
Given: humans are male or female.
T: Jane is human.
R: Is Jane is male or female?
T: Jane is female.
R: Jane is female.
T: describe Jane.
R: Jane is a female human.
Test 3: recall dilemma
Given: humans are male or female.
T: Jane is human.
R: Jane is human.
T: describe Jane.
R: Jane is a male or female human.
Test 4: resolve dilemma with positive
Given: humans are male or female.
T: Jane is human.
R: Jane is human.
T: Jane is female.
R: Jane is female.
T: describe Jane.
R: Jane is a female human.
Test 5: resolve dilemma with negative
Given: humans are male or female.
T: Jane is human.
R: Jane is human.
T: Jane is not male.
R: Jane is not male.
T: describe Jane.
R: Jane is a female human.