Quoted: Basically, capital and investment are the main ingredients in economic growth, said Charles Engel, a professor of economics at the University of Wisconsin-Madison.
But capital and investment can only take you so far. Simeon Alder, a visiting assistant professor of economics at the University of Wisconsin-Madison, said exponential economic growth requires exponential new ideas, as new ideas are the fundamental engine of growth. (Think about the economic growth and improvement in standards of living that occurred during and since the Industrial Revolution.)
“The challenge with that is the more ideas you already have, the more new ideas you need to create in order to sustain that growth rate,” he said. “To get these extra ideas, you just need more and more people as sort of a general result.”