 As these examples illustrate, generics are not equivalent in meaning to any of the quantifying determiners such as “all”, “some”, or “most”. They also differ in meaning from sentences containing adverbs of quantification (Lewis 1975) such as “generally”, “usually”, or “often”. For example, the generic “books are paperbacks” is false, yet the insertion of any of these adverbs of quantification would render the statement true: “books are generally/usually/often paperbacks”.