Creation of universes from nothing.

[Dr H]

...by Professor Alexander Vilenkin:

Creation of universes from nothing

I wish that I could find the original paper, but here's the abstract at least:

A cosmological model is proposed in which the universe is created by quantum tunneling from literally nothing into a de Sitter space. After the tunneling, the model evolves along the lines of the inflationary scenario. This model does not have a big-bang singularity and does not require any initial or boundary conditions.

Hmmm....

I'd kinda like to know what definition of "nothing" is being invoked here.