No Changelings Here

If the first scene in a play is supposed to provide the audience with a roadmap of sorts filled with major themes, then the opening of The Changeling definitely introduces the idea of fate and happenstance. From the very first lines Alsemero describes his apparently accidental first sighting of Beatrice-Joanna:

"'Twas in the temple where I first beheld her,
And now again the same; what omen yet
Follows of that? None but imaginary...
The church hath first begun our interview,
And that's the place must join us into one,"
(I.1.1-3, 10-11)

Judging by his words, he doesn't seem to believe that any omen marks his sighting as being particularly significant, and yet he grants a great amount of importance to the place of their meeting. This is a direct contradiction: how can he claim that he sees no omen in his first seeing Beatrice-Joanna and yet place such a degree of symbolism on an accidental rendezvous? Furthermore, the fact that he saw Beatrice-Joanna and not Diaphanta, and that it was Alsemero and not Jasperino who saw her, seem both entirely unplanned and absolutely necessary. Jasperino is focused on leaving Alicante, but who's to say that if their positions were reversed Alsemero wouldn't have been just as eager to leave? The crucial difference between the two lies in the fact that Alsemero's father had an unknown connection with Beatrice-Joanna's father. Who could have predicted this - and yet, if there were no such connection, it seems very unlikely that Vermandero would have invited a strange man to stay in his home with his engaged daughter in residence. In a very real way, Alsemero had to be the man who falls in love - the one could not be exchanged for the other. Similarly, if Alsemero fell in love at first sight with the eligible Diaphanta, instead of the betrothed Beatrice-Joanna, there would have been no plot because there would have been no inconvenient fiance to eliminate. These characters act as they do, appear where they do because if they didn't, there would be no play, no drama. Whether the hand of fate or of the playwrites, the characters in The Changeling are who they must be. In the original sense of the word "changeling", the play seems most inappropriately titled: the characters clearly aren't interchangeable at all.