In October, 1999, the population of the earth reached 6 billion people. This entire population can fit into the state of Texas with 1000 square feet per person which is slightly more dense than the population density of San Francisco and slightly less dense than the population density of the Bronx in New York. This hypothetical example only underscores more direct and obvious observations that anyone can make for themselves. The earth is not filled. There are vast territories of vacant land outside every major population center in the world. The entire continent of Australia, with a land area nearly the size of the United States, only has 19 million people versus 280 million for the U.S. The continent of South America is so sparsely populated that one cannot find telephones beyond 50 miles outside of population centers because there are not enough people to economically support the equipment placement. The only places that are crowded are places where people have chosen to crowd together to obtain the economic benefits of low cost services. The cost of basic services such as running water, electricity and telephones is substantially reduced on a per person basis when there are a large number of people. A small village with 1000 people cannot afford on its own to pay for a water treatment and purification plant. More advanced services such as machine repair and medical surgery also require a large population base to achieve economic viability. 

India has just reached its one billionth person. It has a population
density of 788 people per square mile. The state of New Jersey has a population density of 986 people per square mile.

Only 11% of the land on the planet consists of cities, villages and farms.