Two people reproduced 7 billion people.

[Aegrus]

Okay, I could be wrong, but if each family had 4 children and generations were 20 years long, the human population would increase exponentially and exceed 7 billion by year 140. My calculator would not be able to display the vast exponent after 6000 years.

Meanwhile, if each family had 2 children, the human race would shrink and die out, given diseases and war.

So, after 6000 years, the difference between human extinction and a population in the thousands of trillions depends on a difference of two children per family.

With that kind of margin per error, there's no way we can possibly draw any conclusions from these equations.

I might have made an erroneous math error somewhere. The 7 billion in 140 years stat seems too insane to be real. Can someone verify if my math is accurate?