Matt Yglesias says:
The world is that which is the case.
You may be tempted just to nod this through. But don't. It's more worrying than you think. For what is the case only makes sense in the light of what isn't the case. That I am, at the moment, alone in this room means that there's no tiger here nor any member of the England football team. Therefore, the world includes Wayne Rooney's absence from my study as well as a shortage of tigers there (here). Determinatio est negatio. But if you think about this, it means that the world is very full of facts - there's an infinite number of them indeed. You look doubtful. (Not pained, or upset, or non-comprehending - but doubtful, which is different.) Yet, as a friend once put it to me:
For every claim starting 'It's not the case that...' there will be a parallel claim shadowing it, saying, 'It is the case that it's not the case... etc.' And if the world is everything that is the case, then all (true) negative claims will be part of the world.
Thus, proving my point. We live in a world full of shadowy negative facts. (Thanks: E.)