It has recently struck me that despite my interest in both physics (as a qualified physicist) and philosophy (as a complete amateur), I have not encountered any philosophy regarding the 'origin' of the universe or indeed aspects of the Cosmos as a whole. While metaphysics is increasingly dealing with questions and dilemmas in modern theoretical physics, I have not seen anyone address the question of *why* the Universe/Cosmos exists. I raise this point purely from a metaphysical standpoint. (The religious aspect is irrelevant.) I am curious whether most philosophers would even think it is a valid question to ask *why* the Universe exists. That is, why not nothing? (I do not mean the Universe is a limited physical sense, as part of a great "Multiverse" perhaps, bus as the all-encompassing everything.) If it does not sound too strange: why does nothing not exist? The temporal problems that some consider; for example the "beginning" and "end" of time do not particularly bother me as a scientist, since time...

There is a considerable literature on this subject. As a place to start, I suggest "Why anything? Why this?" by Derek Parfit, reprinted in "Metaphysics: a guide and anthology" edited by Tim Crane and Katalin Farkas (Oxford University Press, 2004), as well as the discussion of this question in Robert Nozick, "Philosophical Explanations" (Harvard, 1981) -- a large book that touches on many other topics besides this one. Further references can be found in those places. Also relevant are several papers by Adolf Grunbaum and Dean Rickles. There is also a story that Sidney Morganbesser was asked why there is something rather than nothing and replied, "Suppose there had been nothing. You wouldn't have been happy then either!"

Recently I was watching the famous "Powers of Ten" video which starts with a couple at a picnic and moves out to the far edges of the universe, moving ten times further out each second. After this the camera goes back to the couple and enters the hand of the man at the picnic, moving through layers of skin, blood cells, molecules, atoms and finally a haze of interacting subatomic particles. What struck me about this part of the video is that if the camera was to move beyond the boundaries of the man's hand we wouldn't be able to tell. There is no demarcation between the subatomic particles which make up the man's hand and the subatomic particles which make up the surrounding air. So, in what sense do seperate entities exist? Is seperateness an illusion inherent to the experience of beings at a macroscopic scale, similar to our illusion that objects are "solid" when in reality an atom is comprised mostly of empty space?

I love that video! Thank you for your excellent question. Of course, you are correct in saying that there is no sharp demarcation between the hand and its air around it. A water molecule that is part of the hand may at some point evaporate into the surrounding air. There is no particular moment at which the molecule leaves the hand and becomes part of the atmosphere. Its chemical bonds to other "hand" molecules weaken gradually, its distances from those molecules increase gradually, and even if these quantities do not change continuously (in the mathematical sense), there is no magic bond strength or distance at which the molecule officially leaves the hand and joins the air. That being said, the fact that there is no sharp distinction does not guarantee that there is no distinction at all -- that "separateness is an illusion inherent to the experience of beings at a macroscopic scale". After all, there is no sharp distinction between night and day -- yet night is not the same as day. It...