Why expect nothing rather than something? No experiment could support the hypothesis ‘There is nothing’ because any observation obviously implies the existence of an observer.
Is there any a priori support for ‘There is nothing’? One might respond with a methodological principle that propels the empty world to the top of the agenda. For instance, many feel that whoever asserts the existence of something has the burden of proof. If an astronomer says there is water at the south pole of the Moon, then it is up to him to provide data in support of the lunar water. If we were not required to have evidence to back our existential claims, then a theorist who fully explained the phenomena with one set of things could gratuitously add an extra entity, say, Atlantis. We recoil from such add-ons. To prevent the intrusion of superfluous entities, one might demand that metaphysicians start with the empty world and admit only those entities that have credentials. This is the regime imposed by Rene Descartes. He clears everything out and then only lets back in what can be proved to exist.
What really counts here is the probability of ‘There is something’ as opposed to ‘There is nothing’.
This was cited from http://plato.stanford.edu/entries/nothingness/
