The Dragons of Eden: Speculations on the Evolution of Human Intelligence

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At the time of writing, the right / left split of the brain factored heavily into theories of the mind. The left being the seat of analytical and linguistic functions, the right the center of creativity and dreams. More recent neuroscience points to a more modular brain with specialized areas throughout. What's consistent with theories of Sagan's time and today is that much of our brain activity is subconscious, and the sensation that we are actively directing our behavior is largely an illusion. We are indeed creatures of habit, following sometimes ancient patterns, written in the mysterious language of our genetic code. Klopfer, P. H. The Quarterly Review of Biology (December 1978). Vol. 53, no. 4. p. 495. JSTOR 2826736. Sagan’s main springboard for investigating the R complex is Roger Sperry’s seminal work in delineating the separate roles of the left and right hemispheres of the brain. As Sperry demonstrated in amazing split-brain studies, the left brain is more logical and analytical while the right is more synthetic imaginative. Sagan’s contention is that the right brain is really the essence of our reptilian origins, helping us fantasize and imagine, and it’s also a key part of what makes us creative human beings. This is most prominent when we are dreaming. Notice that dreams almost never include details of problem solving, instead they feature highly imaginative scenarios, part familiar and part alien that seem to be largely driven by our fears and hopes: are we partly seeing the world through our ancient reptilian neuroanatomy when we are dreaming, then? Are dreams holdovers from a prehistoric world where, because of inadequate shelter and protection, we had to stay alert and awake during the night to engage with snakes and crocodiles on their own terms? And in the ensuing history of civilization, did reptilian anatomy contribute to our achievements in art and music? Sagan believes that we should encourage the operation of our reptilian brain, constantly tempering its excesses with the logical constraints of the left hemisphere. This distinction between right and left brain behavior also raises very interesting questions regarding whether we can suppress one or another temporarily using drugs and surgery. In fact, it’s likely that that is partly what hallucinogens like LSD do. Here we see Sagan the Renaissance Man, trying to bridge hard scientific thinking with artistic intuition. Published in 1977, Dragons was widely hailed by critics from conventional media sources as a “delight” sure to fascinate readers. Some scientifically trained reviewers were decidedly less glowing, however. Our brain gives us the ability to think about the future and focus on long-term benefits, but we get a lot of anxiety from it and from thinking about our inevitable end.

How can I persuade every intelligent person to read this important and elegant book? . . . He talks about all kinds of things: the why of the pain of human childbirth . . . the reason for sleeping and dreaming . . . chimpanzees taught to communicate in deaf and dumb language . . . the definition of death . . . cloning . . . computers . . . intelligent life on other planets. . . . Fascinating . . . delightful."-- The Boston Globe When archaeologists recently announced the discovery of cave paintings by neanderthals, I was not the least bit surprised. I had just finished reading Carl Sagan's, "The Dragons of Eden", a pulitzer prize winning book from the 1970s on the evolution of the human mind, and came away with the impression that while our brains are one of the most sophisticated structures in the known universe, we also share a great deal in common with our animal cousins.This book is crammed full of fascinating bits of information, intriguing theories, humor, vision, and some caustic observations about society as a whole,” Virginia Tech philosophy of science professor Joseph Pitt wrote in the journal Human Ecology. “What it does not contain is intellectual balance and rigor.” What drew Pitt’s ire in particular was that Sagan spent a significant portion of the book trumpeting a little-known, out-there theory from Yale University physiologist and psychiatrist Paul D. MacLean. Triune brain theory

Unfortunately, all this information has not yet made it into many textbooks. The authors of the aforementioned 2020 review sampled 20 introductory psychology textbooks published between 2009 and 2017 and found that 86% contained at least one inaccuracy suggesting that our brains are layered as MacLean theorized. The Dragons of Eden won a Pulitzer Prize. [2] In 2002, John Skoyles and Dorion Sagan published a follow-up entitled Up from Dragons. [3] Summary [ edit ]

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It has not been done for our dragon design. Another challenging work is casting the minor parts such as the dragon’s horns, mane, scales and legs. These small parts play an important role to decide how amazing our dragons are so we need to focus on them. We try to highlight the sharpness and make the contrast to the entire part of the dragon. The next step after the dragon has already in shaped inside the mold and the Edens colors effect has done. Depending on the color, each step will be different from the other, like waiting for the color beams to settle down, not too long or too short, not too small or too large. Every step is being repeated over and over again and abide exactly the palette of each keycap, each color beam is being created exactly the position that we wants, and no need to discuss about the harmonious. It also takes 8 hours to finish, after all the color beams are on their right positions, we will put it inside the pressure pot, this time we’ll have to wait for around 12 hours. . When keycap have enough time to get hard inside the pressure pot, the next step is cleaning and sanding to create a ultra smooth surface for each keycap. There are 4 step for sanding, and the very last step is create a glowing and clearly surfaces. The calendar starts on January 1st, beginning with the Big Bang. May 1st would be the origin of the Milky Way Galaxy, and September 9th would be the origin of the solar system. Around September 25th, life starts to exist on Earth. By December 16th the first worms exist on Earth, and on December 22nd insects exist. Mammals begin to roam Earth by December 26th but it isn’t until December 31st that the first humans can be found on Earth.

Chimpanzees can abstract. Like other mammals, they are capable of strong emotions.Why, exactly, all over the civilized world, in virtually every major city, are apes in prison? In fact, despite our incredible capacity to reason, we spend an awful lot of time operating out of the tribal, ritualistic, reptilian parts of our brain. The question of whether we will one day sail the galaxies, or blow ourselves up in a nuclear shooting match (or make our planet uninhabitable through environmental damage), is one that Sagan asked for the rest of his life. It's a question that's just as pertinent today. Also, since this book was written in 1977, its safe to say that in the past 40 years someone has written a book on this topic with updated information. But, since I have yet to find that book, I’m giving Sagan a curve and ranking his book a four out of five.Having a large brain compared to our body mass may be one of the reasons humans have been able to survive and rise to the top of the food chain. In their posthumous award to Dr. Sagan of their highest honor, the National Science Foundation declared that his " research transformed planetary science… his gifts to mankind were infinite." D. 1996. Carl Sagan served as the David Duncan Professor of Astronomy and Space Sciences and Director of the Laboratory for Planetary Studies at Cornell University. He played a leading role in the Mariner, Viking, Voyager, and Galileo spacecraft expeditions, for which he received the NASA Medals for Exceptional Scientific Achievement and (twice) for Distinguished Public Service. Carl Sagan is arguably the greatest science writer and educator of recent times. In this book his mind, through his theories, is on full display for all to see. He steps through various evolutionary ideas about how man (and his brain) has evolved. A history of the human brain from the big bang, fifteen billion years ago, to the day before yesterday . . . It’s a delight.”— The New York Times

Dr. Carl Sagan takes us on a great reading adventure, offering his vivid and startling insight into the brain of man and beast, the origin of human intelligence, the function of our most haunting legends--and their amazing links to recent discoveries.Dr. Sagan was elected Chairman of the Division of Planetary Sciences of the American Astronomical Society, President of the Planetology Section of the American Geophysical Union, and Chairman of the Astronomy Section of the American Association for the Advancement of Science. For twelve years he was the editor-in-chief of Icarus, the leading professional journal devoted to planetary research. He was cofounder and President of the Planetary Society, a 100,000-member organization that is the largest space-interest group in the world; and Distinguished Visiting Scientist, Jet Propulsion Laboratory, California Institute of Technology. The reason Sagan dives deep into the Cosmic Calendar is that he is trying to show that humans are incredibly new in the scale of the universe. The universe is ~14 billion years old and modern humans have existed for a ridiculously small portion of time. Science and technology can only tell us so much about the past and our ancient ancestors weren’t developed enough to write down their history but Sagan does his best to explain the evolution of mankind through research from a wide range of sciences. Sagan’s focus is the R complex, part of the “reptilian brain”. It is quite clear that parts of this brain structure are found in reptiles. Reptiles and mammals have an ancient relationship; reptiles originated 500 million years before human beings, so we came into a world that was full of hissing, crawling, terrestrial, arboreal and aquatic reptiles. As Sagan describes, it’s no surprise that many of the world’s foremost civilizations and religions used reptiles as key symbols; from the snake in Eden to the worship of snakes in ancient Egypt to snake symbolism in modern day India, reptiles and human have shared an indelible bond. Reptiles have also often featured as omens in dreams dictating the fates of empires and societies. Some of our reptilian connections raise mundane but fascinating questions; for instance, Sagan wonders whether the shushing sound we make for communicating silence or disapproval is a leftover of the hissing sound of reptiles. At its core this is a thought provoking book that resonates. It is short at only nine chapters so I will review the chapters here — because many are true gems and the rest are pretty good.