Why there is something rather than nothing: The finite, infinite and eternal

Many believe that the deep question of "why is there something rather than nothing?" is unanswerable. The universe just is and no further explanation for its existence is possible. In this paper I explain why this question must have an answer, and why that answer must establish that physical existence is inescapable and necessary. Based on the conclusion that if the universe is eternal rather than having a beginning some finite time in the past, the universe has to exist rather than not because its possible non-existence is never an option, such an explanation is put forward. As a logical extension of only an eternal universe being capable of providing an answer to the question of why there is something rather than nothing, the argument necessitates that the universe must be eternal. The consequences of this conclusion for cosmology are then briefly discussed.