The Dragons of Eden

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The Dragons of Eden: Speculations on the Evolution of Human Intelligence
Dragons of Eden.jpg
The Dragons of Eden cover
Author Carl Sagan
Country United States
Language English
Genre Non-fiction
Publisher Random House
Publication date
Media type Print (Hardcover)
Pages 263 pp
ISBN 0-394-41045-9
OCLC 2922889
LC Class BF431 .S2
Followed by Broca's Brain

The Dragons of Eden: Speculations on the Evolution of Human Intelligence is a Pulitzer Prize-winning[1] 1977 book by Carl Sagan. In it, Sagan combines the fields of anthropology, evolutionary biology, psychology, and computer science to give a perspective of how human intelligence may have evolved.

One of the primary topics featured in the book is the search for a quantitative means of measuring intelligence. Sagan demonstrates arguments that the brain to body mass ratio is an extremely good correlative indicator for intelligence, with humans having the highest ratio and dolphins the second highest,[2] though he views the trend as breaking down at smaller scales, with some small animals (ants in particular) place disproportionally high on the list. Other topics mentioned include the evolution of the brain (with emphasis on the function of the neocortex in humans), the evolutionary purpose of sleep and dreams, demonstration of sign language abilities by chimps and the purpose of mankind's innate fears and myths. The title "The Dragons of Eden" is borrowed from the notion that man's early struggle for survival in the face of predators, and in particular a fear of reptiles, may have led to cultural beliefs and myths about dragons and snakes.

Opening quote[edit]

The Human race is poised midway between the Gods and the Beasts.


  • Introduction
  • The Cosmic Calendar
  • Genes and Brains
  • The Brain and the Chariot
  • Eden as a Metaphor: The Evolution of Man
  • The Abstractions of Beasts
  • Tales of Dim Eden
  • Lovers and Madmen
  • The Future Evolution of the Brain
  • Knowledge Is Our Destiny: Terrestrial and Extraterrestrial Intelligence

Summary of the chapters[edit]

The book is an expansion of the Jacob Bronowski Memorial Lecture in Natural Philosophy which Sagan gave at the University of Toronto. In the introduction Sagan presents his thesis—that "the mind... [is] a consequence of its anatomy and physiology and nothing more"—in reference to the works of Charles Darwin and Alfred Russel Wallace.[citation needed]

In chapter 2, he briefly summarizes the entire evolution of species starting from the Big Bang to the beginning of the human civilization with the help of a "Cosmic Calendar", where every billion years of life corresponds to about twenty-four days of the calendar. The Cosmic Calendar reappears in the Cosmos television series.

It is disconcerting to find that in such a cosmic year the Earth does not condense out of interstellar matter until early September, dinosaurs emerge on Christmas Eve; flowers arise on December 28; and men and women originate at 10:30 P.M on New Year's Eve. All of recorded history occupies the last ten seconds of December 31; and the time from the waning of the Middle Ages to the present occupies little more than one second.

In popular culture[edit]

The book recounts a story, probably fictional, about the lack of accuracy in text translation programs. A deputation that included an American Senator was proudly led to a demonstration of a translation program. The Senator suggested a phrase to be translated, "Out of sight, out of mind". The machine printed Chinese characters and these were then entered into the machine to be translated back to English. The visitors were all astonished when the machine printed the phrase "invisible idiot" on the paper. The computer had literally translated the separate expressions "out of sight" and "out of mind". The anecdote and the phrase "invisible idiot" have entered popular culture.[3]

In 2008 an album called The Dragons of Eden was released by keyboard player and producer Travis Dickerson along with guitar virtuoso Buckethead and drummer Bryan "Brain" Mantia. The album derives its track titles from the book's pages.[citation needed]

See also[edit]


  1. ^ The Pulitzer Prizes: 1978 Winners
  2. ^ pp.38–40, hardback ed
  3. ^ Radio review: Fry's English Delight, The Guardian, 12 August 2009

External links[edit]