I recently finished reading Why Does the World Exist? by Jim Holt. It was enjoyable read. It's a book that I would give to anyone who wanted to know what metaphysics was and what kind of research I do in philosophy.
The book addresses the following question: "Why is there something rather than nothing?" This question is about as fundamental as you can get. The book is basically an exploration of the nature of existence itself. What explains the fact that anything exists at all? Why isn't there just absolutely nothing?
My own take on this issue is that the concept of absolute nothingness is incoherent. Holt talks about the concept of nothingness in chapter 3, but I find his discussion unsatisfying.
My opinion is that nothingness in everyday talk is a local concept. When talk about nothing, we talk about it relative to some context, like a region of space. We might say that there nothing in the refrigerator, or that there's nothing to do in Syracuse. In this respect, the concept of nothingness is similar to the concept of a hole. A hole is a local phenomenon. We use the term to refer to particular regions of space.
Is absolute nothingness conceivable? What is absolute nothingness? When most people imagine absolute nothingness, they imagine empty space. But is that really nothing? Couldn't empty space itself be something? In fact this is a view that's argued for in metaphysics. It's called "substantivalism." Suppose that empty space itself is something. Then can imagine a reality without empty space? What it be like? Seems inconceivable to me.
It's kind of like trying to imagine a reality with no color. People say that black is the absence of color. This never made sense to me. If black is the absence of color, then what color is a piece of glass? It's not black. Since it's not black, is it therefore colored? That seems absurd. I hold, therefore, that black is indeed a color, and to be colorless is to be completely transparent, like a piece of glass. Suppose, then, that the universe was completely colorless, i.e. completely transparent. Is this imaginable? It wouldn't be black, it wouldn't be white, just transparent. Seems inconceivable to me. I think that absolute nothingness is like complete transparency.