"Although the Big Bang Theory is mathematically sound, the a priori
existence
of a nearly infinite supermassive density from which the big bang arose
is
an unsupported assumption that doesn't make physical sense."

The BB theory does not make this assumption. The BB theory assumes that
where the BB occured in what is known as the quantum vacuum--that is a
vast
volume of space with absolutely nothing (bigger than quantum
fluxuations).