Our observable universe is just that, the portion of space which is observable. However, there is space beyond what we can see and light is expanding into it right now. If that space were infinite we would be confronted with the fact that all things are possible and there are infinite universes in which every possibility is playing out. An accusation levelled against this theory is that it is not parsimonious, but it does not waste space or atoms. The equations are actually extremely parsimonious because they are elegant and provide much more than is inputted.