When discussing, say, predictions for the ending of a novel, I've often heard logic along the lines of:
This character must survive, because if (s)he doesn't, the story would be [depressing/underwhelming/meaningless/etc.].
Is there an English term for this? I was thinking it could be some form of prediction, expectation or perhaps "predestination", but I can't find a logical adjective to add to refer to this specific form. Note that I am not looking for a description of the validity of this technique, just the usage itself.