PHILOS 31 Lecture Notes - Lecture 5: List Of Cluedo Characters, Natural Deduction, Logical Biconditional
Document Summary
We will use a natural deduction system to show that arguments are valid. Natural deduction systems closely resemble the way that people think and argue than many other systems. A proof, or a derivation, consists of a series of lines,e ach of which is justified by a rule of our system and may have sub-proofs. If premises are true, then conclusion must be true to prove validity. Has 3 columns- line number, formula, and justification. Has 3 types: direct, conditional, and indirect: direct- looking to show the conclusion only, show p. Example: miss scarlet is in the billiard room. Either the rope is in the study or plum didn"t do it. If plum didn"t do it, then mustard did. If scarlet is in the billiard room, then the rope isn"t in the study. Line 8 is what we want to show.
