n Proposition Symbol Explanation 1 Peter is gay. P1 Premise 2 Peter is male. Q From 1 Valid? Perhaps. A truth table with show: P Q ¬Q P∧¬Q T T F F T F T T F T F F F F T F If the superconjunction of all the premises and the negation of the conclusion comes out as necessarily false (F on all rows), then the argument is valid. Or equivalently: An argument is valid iff the superconjunction of all the premises and the conclusion is a necessary truth. (I.e. all rows come out as T.)

## Valid arguments, contingent truths & forms

## Valid arguments, contingent truths &…

## Valid arguments, contingent truths & forms

n Proposition Symbol Explanation 1 Peter is gay. P1 Premise 2 Peter is male. Q From 1 Valid? Perhaps. A truth table with show: P Q ¬Q P∧¬Q T T F F T F T T F T F F F F T F If the superconjunction of all the premises and the negation of the conclusion comes out as necessarily false (F on all rows), then the argument is valid. Or equivalently: An argument is valid iff the superconjunction of all the premises and the conclusion is a necessary truth. (I.e. all rows come out as T.)