$P_1$: If logic or set theory are important, then students learn them.
$P_2$:Logic and calculus are important.
$P_3$: Therefore, students learn them.
Given 3 propositions above. Actually, there are 3 questions asked here: change the propositions into logical symbol, create the truth table and the truth value of the propositions, and check the validity. I have no problem for the first one and also making the truth table. But, I have some doubt when facing: the truth value of the propositions and check the validity. After I make the truth table, how can I determine the truth value? and then what requirements needed to make premises/sentences above valid or not (how to determine its validity?)
My idea: The truth value is determined by fact/reality, is not it? For instance, Jakarta is the capital city of Indonesia. (true) But, how can we make sure that everyone thinks that calculus, logic, or set theory are important?