How do you know he will be willing to do your laundry, wash your car and get you beer?

Because the theory outlined in the article says that somewhere, in a parallel universe, there is an exact copy of me who WILL be willing to do it. Telling him apart from the infinite number of other copies of me that aren't willing to do it would be difficult, though.

And if that doesn't work, I'd split the beer with him, and, if he's an exact copy of me, he'd be okay with that arrangement.