stephen and others were worried that since black holes were anti-matter that there was a great possiblitity that all these black holes would combine and create on big black hole effectively cancelling out all matter... upon further study stephen theorized that there were multiple dimentions if you will that all existed one on top of another... and somehow he mathematically proved that where one black hole existed in one dimension it did not in another... therefore the balance was maintained between anti-matter and matter and there was no threat that a universal black hole would swallow everything up... this was pretty recent you could probably check into it if you don't believe me...