Hmm, well... you could shake the box and see if it meows, or feel it to see if there's any warmth coming from a living cat... what in the heck kind of theory is that? Just because no one can see the cat in the box, it's completely random whether it's alive or dead? It'd be logical if, provided the cat had something to eat recently, a sufficient supply of breathable air, and no gooey bombs stuck to it, the cat were alive. It'd be logical if, given that the cat were low on food, had no oxygen, and did have gooey bombs stuck to it, the cat were dead. There's also the possibility that the box contains no cats, but that's not a random occurrence either.
Also,
There = Over there
They're = They are
Their = Possessive
Thier isn't a word. I'm sorry... you've awoken the Grammar Queen. And MaxVance is the Grammar Princess, remember? Good times...