Carl Sagan’s The Dragons of Eden: Speculations on the Evolution of Human Intelligence, was recommended to me when I was attending banking school by an instructor that gave us a list of “non-business” books we should read. It was my first Sagan book and found it to be quite enjoyable. Carl Sagan reads like a philosopher at times and this book particular book is a nice blend of scientific facts and Sagan’s educated leaps based on evidence. This book certainly came to me at a time as I began to slowly contemplate our species, our development and the future we are creating.
In true Sagan fashion he opens each chapter with thought provoking quotes spanning across literature, philosophy and the Bible itself. Early on he quotes John Milton from his work Paradise Lost, “Then wilt thou not be loth to leave this paradise, but shall possess a paradise within thee, happier far… They hand in hand with wandering steps and slow through Eden took their solitary way.” He ties, from his point of view, the evolution of man and the development of the human brain as a startling masterpiece. An interesting point he makes very early on is, “Biology is more like history than it is like physics; the accidents and errors and lucky happenstances of the past powerfully prefigure the present.” Dr. Sagan’s emphasis on chance made me feel insignificant but also fortunate at the same time. The human brain has giving us much and he makes a great point, “Man is probably the only organism on Earth with a relatively clear view of the inevitability of his own end.”
Sagan makes the study of the brain seem more simple than it actually is in his writing which helped me understand the mechanics better than I did prior to reading. He writes, “The human brain contains about ten billion switching elements called neurons. The cerebellum, which lies beneath the cerebral neocortex, toward the back of the head contains another ten billion neurons.” I think that it is important to reflect at times on how magnificent the human brain truly is, “The brain is therefore ten thousand more densely packed with information than a computer.” The marriage between evolution and brain development is inseparable in this book as well. Dr. Sagan writes very clearly on the matter and defends against naysayers, “At the most ancient part of the human brain lies the spinal cord; the medulla and pons, which comprise the hindbrain and the midbrain. This is the neural chasis it contains basic neural machinery for reproduction and self preservation, including regulation of the heart, blood circulation and respiration.”
The true focus of this book is: the neocortex. Which makes sense because the neocortex comprises about 85% of the human brain. Sagan writes, “Clearly the most recent evolutionary accretion is the neocortex.” It has given us the higher mental powers mechanically over all other species and not to discount other animals but the true power of self-consciousness. He makes note that many ‘nonhuman primates’ are on the edge of language although many species possess gestural language as well. To quote him, “Human language is controlled in the neocortex. Thus an essential step in human evolution must have been the transfer of control of vocal language from the limbic system to the temporal lobes of the neocortex, a transition from instinctual to learned communication.” I couldn’t help but to reflect on humanity, our growth and our future as I flipped through (digitally) the pages of Sagan’s work.
To close out, Dr. Sagan addresses some of the larger issues towards the end of the book. I really appreciated his take on “when personhood begins”, although different than my own personal take it was at least well thought out and made sense by scientific standards or at least from what I could tell. His argument was that a human becomes a human (or deserves the rights of a human that we assign in the modern world) when the neocortex develops which is about 4-5 weeks into a pregnancy. I have become somewhat of a futurist lately as I have thought a lot about the direction of civilization. Sagan comments on our species’ desire to merge more with technology, “The next major structural development in human intelligence is likely to be a partnership between intelligent humans and intelligent machines.”
This is a great, challenging and fascinating read. Sagan was well read in religion, history, philosophy and was one of the most influential scientists of our time. Regardless if you align with Dr. Sagan or not, he certainly deserves a place in your library. I found this book to be very stimulating and his opinions were all backed strongly with facts. I am going to make it a point to incorporate scientific literature in my reading habits. He closes with, “Science is only a Latin word for knowledge… Knowledge is our destiny.”
Written by Michael McPhail
Brains and Brawn 