Charles Darwin on immigration

Based on the enormous number of people migrating to the United States during his lifetime, Charles Darwin predicted that the U.S. would soon be counted alongside the most powerful empires in history. His reasoning was simple: To move from one country to another requires an enormous amount of courage and energy - to take that journey you had to leave everything behind, cross an ocean and start a new life for yourself without any guarantee of success on the other side. Therefore, after many waves of immigration into the United States, the country would inevitably be brimming with so many highly-motivated people (demonstrated by their willingness to take that journey in the first place) that its workforce would have to be one of the most industrious in the world. Migration was, in Darwin's view, a kind of natural selection acting to weed out people who lacked the courage and ambition to leave home.


Reference:
Darwin, C. R. 1882. The descent of man, and selection in relation to sex. London: John Murray. 2nd edition. (p.142)

"Immigrants are taking all our jobs"

Population increases, whether due to immigration or births mean more workers vying for whatever jobs are available, but they also mean that there will be more jobs available because there will be more customers that need to be served and hence more staff needed to serve them. This is why a country with 100 million people will not generally have a higher unemployment rate than a country with 50 million.