Formal System for PL

Like what we have done in the previous chapter, we will apply the same idea but this time to predicate logic otherwise known as First-Order Logic (FOL). Predicate logic is called FOL because the logic speaks about objects and their relationships with other objects. When we speak about something, we are predicating it, like in saying “John got infected by a virus”. In general, FOL speaks about individuals. When we are predicating on a predicate itself, or we are speaking about sets of sets, then this is now the realm of higher order logic (HOL), which is beyond our scope.