History is not a guide here. Prior to this century, people needed to be located together to collaborate. That is not the case anymore.

In the early 1900s, when the world had 2 billion people, we invented General Relativity and Quantum Mechanics.

We don't need more people.

All of the world's biggest problems are due to over-population:

1. Climate change - would not be a problem if there were only 2 billion people, because energy use would be much less.

2. Pollution - would not be a problem.

3. Over-fishing - would not be a problem.

4. Ocean acidification - would not be a problem.

5. Rising apartment rents due to urban density - would not be a problem.

There are too many people.