Stage Six- Introduction to Deduction
Logical Form - sentences
The logical form of a sentence is its structure, without reference to its content (what it is about).
Logical structure is composed of two parts - variables for sentences (p, q, r), and logical connectives (not, and, or, if-then).
Start by identifying all logical connectives in a sentence. The parts that are left are assigned variables.
Logical form - arguments
Modus Ponens: If P, then Q. P, therefore Q.
Modus Tollens: If P, then Q. Not Q, therefore not P.
Disjunctive Syllogism: P or Q. Not P, therefore, Q.
Hypothetical Syllogism: If P, then Q. If Q, then R. Therefore, if P, then R.
Dilemma: P or Q. If P, then R. If Q, then R. Therefore, R.
Example #1 (0:00) - sentence translation (easy)
Example #2 (2:07) - sentence translation (medium)
Example #3 (3:25) - sentence translation (hard)
Example #4 (5:27) - argument translation