All unknown and merely presumed by faith in naturalism.
The dictionary does not place a time or number of processes limit on 'spontaneous', although I understand why you would need to.
Huh? I don't even understand that assertion, except as some sort of bizarre and extreme intellectual (or anti-intellectual) relativism. How the term "spontaneous generation" has historically been used in science is not an issue of "faith," but rather an issue of examining the actual history, or scholarship regarding that history.
I happen to have read rather beyond the depth of the average layperson in the history of biology and natural history, and have consumed several books covering the spontaneous generation controversies alone.
I know what I'm talking about here. You don't.