A boolean is either true or false - i.e., it's the type inhabited only by "True" plus the type inhabited only by "False". An integer is either 1, or 2, or 3, or

A boolean is either true or false - i.e., it's the type inhabited only by "True" plus the type inhabited only by "False". An integer is either 1, or 2, or 3, or 4, or..., i.e., it's the countably infinite sum of other types.