I would love to see what a bunch of different science fiction and fantasy writers would come up if given the assignment to write a story titled "Vampire Robot," with no other guidelines as to content or tone. Maybe someday I'll have the juice to put together a high-concept anthology like that.
Controlling for certain variables is key in scientific experimentation. You can't know what's causing (or not causing) a particular effect unless you keep constant every factor except the one you're testing. And even then, previously unknown forces may affect your outcomes (hello, dark matter).
Don't get me started on the difference between "hypothesis" and "theory."