Phil 105: Critical Thinking - Day 4: Entailment

read the slideshows becuz this isnt enough

MODUS PONENS

1. If P, then Q

2. P

3. Therefore Q

MODUS TOLLENS

1. If P, then Q

2. Not Q

3. Therefore, not P

HYPOTHETICAL SYLLOGISM

1. If P, then Q

2. If Q then R

3. Therefore if P, then R

DISJUNCTIONS

eg. or, either or

BINARY CONNECTIVE

or is a prime example (eg. (either) P or Q)

DISJUNCTIVE SYLLOGISM

1. Either P or Q

2. Not P ( or not Q)

3. Therefore, Q (or P)

PREDICATE FORM

turning arguments into the forms we have been using

COUNTEREXAMPLE

used when the logical form is invalid

BIASED EVALUATION

Prejudices or pre-existing views can cause us to misidentify entailment if we fail to decouple.

Common invalid forms:

1. Affirming the consequent

2. Denying the antecedent