Who said "Human nature is the most interesting thing we can study."?

This quote is attributed to Carl Sandburg.

Human nature is the most interesting thing we can study. - Carl Sandburg

"Human nature is the most interesting thing we can study."

Carl Sandburg Philosophy

Poet American 1878–1967

"I am the people—the mob—the crowd—the mass."

"Life is like an onion; you peel off one layer at a time and sometimes you weep."

"Nothing happens unless first we dream."

"I have always been ahead of my time."

"I've seen the worst humanity has to offer."

"Sometimes I wonder if the world is worth saving."

"Every choice shapes our destiny."

"Order is the foundation of a good life."