I would call this 'An Argument for the Necessity of the Universe', riffing off the WMU post where I've been commenting, but I don't really have any arguments to offer. Just a nice picture. Here's how it looks:
The world (universe) is essentially spatiotemporal. Each so-called 'possible world' constitutes a different form the physical manifold might take -- a way the world could be. Collectively, they exhaust the possibilities. That is, the world must instantiate one of them. The manifold is given; all that varies is its form -- but it must take some form or other. Big or small, the one necessity is that it is something, rather than nothing at all.
Pretty, no? (Admittedly, there's still the question why it takes this form rather than some other.)