I think a good discussion / activity to go with Chapter 1 of my textbook is to have students come up with a list of “public goods” and then ask if they are truly, strictly speaking, non-excludable. You don’t want to confuse them, but it might be worth thinking about the concept more closely and, it the process, ingrain in them the understanding that the technical definition of “public goods” means less than by what people often say are public goods. For example, a lot of things that most agree are socially beneficial (e.g., parks or roads) actually are excludable and therefore not actually “public goods.” We just choose not to exclude because we want “public” (i.e., universal) access. But it is only because of this strict definition of “public goods” as non-excludable goods that we can say that providing public goods is someting that all governments purport to do. Not every government makes a priority of providing public parks or universal literacy. But all governments claim to provide non-excludable goods like “national defense” and “order.”
Link to US Civitas Facebook Discussion Thread