For most of the first half of the 19th century, the scientific community believed that, although geology had shown that the Earth and life were very old, human beings had appeared suddenly just a few thousand years before the present.
Selama sebagian besar paruh pertama abad ke-19, komunitas saintifik meyakini bahwa, meskipun geologi menunjukkan bahwa Bumi dan kehidupan sangat tua, manusia muncul mendadak beberapa ribu tahun sebelum saat ini.