What is the concept that the following statements are based on? 'Propositional logic is not concerned with determining whether each simple proposit...

What is the concept that the following statements are based on? 'Propositional logic is not concerned with determining whether each simple proposition is true or false. That information has to come 'from outside' to logic. Once truth values have been assigned to each simple proposition that we are interested in (i.e., we have been told for each one whether it is true or false), the truth value of complex propositions can be calculated from that information. A valuation represents the information that has to come from outside: each propositional letter, which represents a simple proposition, is assigned a truth value. From there, using truth tables, the truth value of a complex formula can be calculated.'

Propositional logic is not concerned with determining whether each simple proposition is true or false.
Truth values have to come from outside to logic.
Once truth values have been assigned to each simple proposition that we are interested in, the truth value of complex propositions can be calculated from that information.
A valuation represents the information that has to come from outside: each propositional letter, which represents a simple proposition, is assigned a truth value.
From there, using truth tables, the truth value of a complex formula can be calculated.
a) The concept of truth tables.
b) The concept of propositional letters.
c) The concept of valuations.
d) The concept of complex formulas.