Learn in the textbookSymbolic AI and Logical Reasoning
DefinitionPredicate logic (述語論理) is a logic that expresses the properties of objects and the relations between them with symbols of the form "predicate(object)."
ExplanationFor example, "Kitty is a cat" is written Cat(Kitty), where "Cat" is the predicate and "Kitty" is the object. Adding quantifiers (∀ and ∃) for "all" and "some" lets you write general rules that hold for many objects, which makes it the foundation of symbolic AI, where people write knowledge as symbols and rules and let the machine reason with it.
AnalogyIf an address book has fixed fields such as "name" and "relationship," a computer can pick out who is whose parent. Predicate logic is a way of putting knowledge into that kind of fixed format.
Memory hookPicture a function call: the predicate goes first, like a function name, and the things it talks about go inside the parentheses.