Thomas Malthus

"Population, when unchecked, goes on doubling itself every 25 years or increases in a geometrical ratio."

"In a state therefore of great equality and virtue, where pure and simple manners prevailed, the increase of the human species would evidently be much greater than any increase that has been hitherto known."

"I do not know that any writer has supposed that on this earth man will ultimately be able to live without food."

"I think it will be found that experience, the true source and foundation of all knowledge, invariably confirms its truth."

"The superior power of population cannot be checked without producing misery or vice."