 (3) is necessarily true. Suppose (4) is true. If “Jack the Ripper” works as a proper name, (4) is necessarily true, too (Barcan Marcus 1947; Kripke 1980). Thus, (3) and (4) are necessarily equivalent. But (3) is uninformative (you already knew things are self-identical), whereas learning (4) could save your life. Information, this fundamental concept of our age, also seems to display hyperintensional features. The difference between (3) and (4) is marked by saying that you can know (3), not (4), a priori. The concept of a priori, then, has hyperintensional features too.