3 Formalisation in Propositional Logic

Question 1

Define truth-functionality

Answer 1

A connective is truth-functional iff the truth-value of the compound sentence cannot be changed by replacing a direct subsentence with another sentence having the same truth-value

Question 2

Define the scope of a connective in L1

Answer 2

The scope of the occurrence of a connective in a sentence ∅ of L1 is the occurrence of the smallest subsentence of ∅ that contains this occurrence of the connective.

Question 3

An english sentence is a tautology iff its formalization in propositional logic is ———

Answer 3

logically true

Question 4

An english sentence is a contradiction iff its formalisation in propositional logic is ——–

Answer 4

a contradiction

Question 5

A set of english sentences is propositionally consistent iff the set of all their formalizations in propositional logic is———-

Answer 5

semantically consistent

Question 6

What makes an argument in english propositionally valid?

Answer 6

Iff its formalization in L1 is valid