Shea stadium is not Eden, and the picture of Tom and Nancy Seaver leaving its graceless precincts in tears did not immediately remind me of the Expulsion of Adam and Eve in the Brancacci Chapel. And yet, absorbing the feelings generated by Seaver’s departure from New York led me to the kind of inflated cogitation that links Masaccio and the Mets, if only because the feelings were so outsized and anguished and intense. After all, Brad Parks had gone to Boston, and Namath to Los Angeles, and Julius Erving to, if you will, Philadelphia. Clearly evil had entered the…