Book Review – The Dragons of Eden

Until now, my coverage of Carl Sagan’s The Dragons of Eden has been on a chapter to chapter basis presented in the “Read Along” section of the blog. As mentioned in my last post,  I will be scrapping this in favor of exclusive reviews on selective books I wish to discuss, henceforth. So, without further delay, let’s bring the curtains down on The Dragons of Eden.

Carl Sagan, noted astronomer, science communicator, and author of The Dragons of Eden.

The premise of the book is clearly stated in the subtitle: “Speculations on the Evolution of Human Intelligence.” Sagan wishes to explore the various facets of human intelligence by calling to motion a simple question: why are humans, humans? He attempts to investigate, in what has been a shared effort by the academic community, a conclusive answer to this question from a purely scientific viewpoint while entertaining “occasional excursions into myths, ancient and modern.” The title of the book supports Sagan’s approach in a compilation of ideas on the “unexpected aptness” of various different myths when compared to scientific theories.

Beginning with time immemorial at the Big Bang, we ride the waves of time flowing toward the current epoch of human civilization. Human evolution is often described in the form of a metaphor, an “abstraction of beasts,” as Sagan uses various comparative arguments to build the foundation of his work in the earlier chapters, particularly in Chapter 2 – Genes and Brains (which I provided a full summary of in the Read Along), before settling into the pivotal point of his work which focuses on the evolution of human intelligence in the subsequent chapters describing the characteristics of the human brain and its evolutionary growth.

Very old are we men; our dreams re tales told in dim Eden… – Walter De La Mare “All That’s Past”

Following the footsteps of his predecessor in Jacob Bronowski, whose work in The Ascent of Man is an account of how human beings and human brains evolved, Sagan has presented his own unique approach to the same subject in his book.  While we don’t necessarily discover an absolute answer on the origin of human intelligence, Sagan’s book is nevertheless an exhilarating journey that offers his insight into the brains of man and beast, the plethora of recent discoveries in science supporting the theory of human evolution, and most interestingly how they serve to be the function of our most familiar myths, and legends. 

Sagan’s work doesn’t end there. His arguments and words serve as microphone toward the need for intellectual rigor, and a rejection of the absent skepticism prevalent in modern-day society. Altogether, The Dragons of Eden is an excellent book that talks about all kinds of things, from the reasons for sleeping and dreaming to the definition of death in what is a fascinating and delightfully short compendium of knowledge that should be read by everyone alike. Sagan was an influential science communicator (one of my favorites), if not one of the best; his works are well worth the effort of reading for anyone interested with or without a scientific background.


Book Review: A Brief History of Thought

Luc Ferry’s A Brief History of Thought recently caught my eye as I wandered through the library. The book promised a brief summary of human thought and its evolution across significant historical epochs within a meager volume of pages. Who wouldn’t wish to entertain such a prospect?


The book’s strength is in Ferry’s ability to summarize various complicated worldviews with such simplicity, and conciseness. While I can’t call upon an extensive knowledge of philosophy to critique Ferry’s work, I certainly identified my share of agreements and disagreements with the opinions and perspectives proposed in the book. In this review, I will summarize Ferry’s claims and arguments, which while insightful and highly educational, personally, fell short of convincing by the final pages.

Ferry begins by addressing the question at the heart of human existence, a quest for salvation (an answer to the mystery that is death), which he identifies to be the vital aspect of every philosophical system. Characterizing philosophy as more than an act of reasoning and logic, Ferry asserts that philosophy is also a measure of human thought that “claims to save us – if not from death itself, then from the anxiety it causes, and to do so by the exercise of our own resources and our innate faculty of reason.”

From there on, Ferry uses this argument as a guide to expound his views and perspectives on the various philosophical movements that have spanned the history of human thought: Stoicism, Christianity, Humanism, Postmodernism (Nietzsche), and Contemporary philosophy (post-Nietzsche). The book flows smoothly from one time period to another while providing an effective summary of the relevant aspects of each philosophical movement. By the end of each chapter, the reader is able to identify the questions and answers that serve as the foundation for the consecutive movement.

We are first acquainted with the Greeks and their establishment of Stoicism, the representation of the world as a perfect cosmos, an ordered logos where transcendence and immanence are united; a cause that the human strives to be a reflection of.

Cosmos refers to the explicit complexity, and perfection of the external universe. Logos defines the divine reason implicit in the cosmos, providing it order and meaning.

The impersonal  approach towards death and salvation in Stoicism is rectified by Christianity where the human is the focal point of the argument. Unlike in Stoic reflections, salvation is personalized through the evocative belief  in a Son of God, a motion towards “love in God,” promising fulfillment and an immortality where we maintain our personal identities.

The foundations upon which both Stoicism and Christianity rested soon come crashing down with the advent of science. Modern physics reveals “an infinite chaos devoid of sense; a field of forces and objects jostling for place without harmony.”


Thus, mankind is once again alone in a cosmos void of a logos or god of any kind. Reality is marked by chaos. The Stoic measure for study or contemplation and the Christian revelation fall flat against the ensuing chaos.

The human is once again the focal point of the argument, but this time, “it was going to require man himself…to introduce some order into a universe which seemed no longer to offer any of its own.” Man’s ability to devise a personal history distinguishes him from his animal brethren resulting in a Humanism that takes the reigns in a movement where humans forge the history of the world through the ideals and laws we invent to judge our actions and their consequences. Nevertheless, humanism stumbles in offering a solution to our quest for salvation, leading to a well-defined struggle that lasts to this day between the various pantheons of human thought.

The cycle doesn’t end here as we alight upon the arrival of Nietzsche and Postmodernism. Nietzsche dismissed both science and religion. His critical deconstruction of the conventional philosophies of the time focused on their inseparable similarity that adhered to a disregarding of the essence of life, and instead building metaphysical constructs/ideals to allow the human to find “salvation” or a purpose.

“People don’t want to hear the truth because they don’t want their illusions destroyed.” – Friedrich Nietzsche

All of which Nietzsche believed was nothing more than a lie, a negation of life from what it essentially is by supplanting it with transcendental ideas of god, and the ideal human being. Nietzsche’s nihilism would fuel his famous ideas for the “will to power,” an attempt for control in a deconstructed universe by the self physically, emotionally, and also morally.

Ferry concludes his work by providing an assessment of modern day Contemporary philosophy in the wake of the revolutionary movements summarized above. This concerns a world where there is no longer a universal meaning towards human existence, but rather an incessant and a seemingly directionless promotion of progress for the sake of progress, a morose form of materialism.

In conclusion, Ferry provides a wonderful and enlightening primer on the various philosophical attitudes that span the history of human thought. I would certainly recommend this book for any philosophy enthusiast. The reader gets a taste of the major aspects of Western philosophy over the vast vista of time. Nevertheless, the  fact that the book is a philosophical overview for a mass audience makes it a tough prospect in accurately capturing the more subtle facets of the various philosophies discussed. While this can be seen as a weakness, it is also a strength, as it will drive the interested reader to learn more about the topics involved (it did for me). Though Ferry himself stumbles in deriving a clear answer to the human quest for “salvation,” his work succeeds in emphasizing the significance of said journey in that it is defining of our very humanity, and individual spirit. In that vein, A Brief History of Thought is a wonderful journey in itself.



A few months ago, I had visited my family at Bangalore, India. Returning to my homeland was a nostalgic experience. During this period, my family, and I took a trip to a biological park.

While I enjoyed my time at the park, the excursion accompanied a fair share of contemplation on my part particularly with regards to the treatment of the world’s wildlife, and environment.

As much as I enjoyed observing the various species of animals that the park hosted, I felt a certain measure of guilt, remorse, and even anger at the state of said animals within their caged amenities.

I felt distraught that the freedom of said beasts, so majestic, was dampened within these structures, structures that were all too human; built around our ego, and will for dominance that have left us blind to the truth that we all depend on the measured balance of the ecosystem for survival.

While we pride upon our intellect to differentiate, and set us apart from the beasts, it grieved me to think, that in this modern day, and age humankind continues to  digress to a base notion of primacy in its interaction with other species on this planet, and the environment.

Ruminating on these thoughts, I passed by a message upon our departure from the park. Carved along the head of a rock, the message read, (as I recall, it was a quote by the founder of the institution)

 The survival of man is dependent on the survival of animal, and plant life.

Providing poetic irony to my reflections, the message inspired me to write the poem below, a brief meditation on the Cages that imprison human nature.


Those shadows stare,
The blackened soot of their vacant eyes,
Clamoring against the leering smiles,
Forcing open the void from whence,
Comes that onerous resonance,
Tarnished ivories gaping amid the sputum,
Coagulating in the filth of their stature,
Wrinkled by the posture of their pride,
Dictating their steps,
Upon the earth they tread,
Mutely claiming what they desire,
Declaring their supremacy,
In these rusted chains,
So to rest,
Behind these bars,
Where this existence caged,
In limbo dwells,
Awaiting the spell,
That falls to the ground,
Submitting to the prejudice of vanity,
In ignorance of an action,
That remains,
Human, all too human…

“They’re animals, all right. But why are you so goddamn sure that makes us human beings?” – The Long Walk, Stephen King


The Dragons of Eden-Chapter 2- Genes and Brains



Biological evolution accompanies a linear increase in complexity. Look around you, it doesn’t take much time for us to realize that our world is quite complicated. The Earth hosts a variety of taxa (species, subspecies, and races), with the major taxa, which have evolved most recently, being the most complex. Humans, or homo sapiens, are in this bracket.

It is easy for us to identify, on the basis of our physical and mental attributes, functions and behaviors, factors that may set us apart from others, and contribute to our unique identity. By doing so, we have merely partaken in a significant evolutionary behavior, namely the ability to identify differences among ourselves, as opposed to other species, including members of our own taxa. Most often, we relegate our comparisons to distinctions based on the quantity, and quality of characteristics.

In this chapter, Sagan uses this notion as a medium towards the deeper understanding of our evolutionary history as a species by addressing the history of life in the gradual dominance of brains over genes.

The Book of Life

While a primitive notion on the complexity of an organism can be obtained by considering its behavior, and functions, we can do the same by considering the minimum amount of information contained within said organism. In other words, how much genetic material does the organism hold?

The book of life is written in the language of four alphabets, consisting of complex molecular structures called the nucleotides. DNA (Figure 1), or Deoxyribonucleic acid, the primary hereditary molecule, consists of about five billion pairs of nucleotides. In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes.

Figure 1. The four alphabets of DNA, the nucleotides: Thymine, Adenine, Guanine, and Cytosine.

All the organisms on Earth share this genetic language composed of four alphabets, leading to the theory that we are all descended from a single ancestor, or a single instance of life some billion years ago.

“If there are approximately six letters in an average word, the information content of a human chromosome corresponds to five hundred million words. If there are about three hundred words on an ordinary page of printed type, this corresponds to about two million pages. If a typical book contains five hundred such pages, the information content of a single chromosome corresponds to four thousand volumes.” – Carl Sagan, The Dragons of Eden

Brains vs. Genes

The gradual dominance of brains over genes, the premise of this chapter, is shown to follow a practical necessity in the evolution, and survival of various species. The main working materials of evolution are mutations (Figure 2), heritable changes in the nucleotide sequences of our DNA.

Figure 2. Well, not exactly…but you get the point. 

Most mutations/genetic changes are too slow for any practical benefit (occurring over millions of years). Most mutations are also harmful, and in some cases recessive. In the end, what really counts are mutations in the gametes, the eggs and sperm cells, the agents of sexual reproduction.

“Large organisms such as human beings average about one mutation per ten gametes-that is, there is a 10 percent chance that any given sperm or egg cell produced will have a new and inheritable change in the genetic instructions that determine the makeup of the next generation.” –  Carl Sagan, The Dragons of Eden

With such a high mutation rate to already cope with, a greater complement of DNA could suggestively result in unacceptably high mutation rates. Too much would go wrong, for anything to stay right! As Sagan postulates, there must be a practical upper limit to the amount of genetic information that the DNA of larger organisms can accommodate, thus by the same instance, necessitating the existence of substantial resources of extragenetic information to allow for their survival, and growth. Such information is contained in all “higher” organisms, except humans (who have invented extrasomatic knowledge, or information stored outside our bodies, like writing), exclusively in the brain.

Peering Into The Brain

The remainder of the chapter an exclusive tour de force of the brain. The corresponding questions, and their central arguments can be summarized as follows,

What is the information content of the brain?

There are two extreme opinions on brain function:

(a) The brain or the cerebral cortex (its outer layers) are considered to be equipotent; there is no localization of function, such that any part of the brain can substitute for another.

(b) The brain is completely hard-wired, and specific cognitive functions are localized in specific parts of the brain.

The actual answer lies somewhere between the two as has been portrayed by various experiments over the years. Modern-day neuroscience continues to address this question.

Is there a correlation between brain mass, and intelligence?

There isn’t a one-to-one between brain mass or size and intelligence in human beings, but there remains a statistical correlation nonetheless (namely in that there are upper and lower limits which may correspond to normal adult human brain function). It has been found that the correlation between brain size, and intelligence is much better than the correlation between intelligence, and adult body weight. Sagan presents the criterion of brain mass to body mass, with no consideration of behavior to provide an acceptable first approximation for intelligence.

What is the structure of the brain, or how is it packed?

The human brain contains about ten billion switching elements called neurons. There is contention among neurobiologists that neurons are the active elements in the brain, as evidence has been provided that specific memories and other cognitive functions are contained in certain molecules in the brain, like RNA or small proteins. An average neuron in a human brain is said to have been 1000-10,000 synapses. If we were to consider each synapse as equivalent to a on-off state, then the number of different states of a human brain is far greater than the total number of elementary particles in the entire universe. We are all truly unique!

The brain is basically a system of microcircuits, and a very dense on at that with an information content of ten billion bits per cubic centimeter. As Sagan points out, a modern computer able to process the information in the human brain would have to be about ten thousand times larger in volume than the human brain. Though the processing speed of a computer is far higher than the brain, the fact that our brain can do so many significant tasks so much better than the best computer is a testament to how tightly packed, and well-organized it is. We have yet to break this mystery, and come to a complete understanding of the brain, and its functions.

The End Game

Thus, having considered the quality and quantity of genetic material, and brain information in organisms, Sagan is able to compare the gradual increase through evolutionary time of both the genetic, and brain information of organisms, showing that somewhere around the Carboniferous period, a few hundred million years ago, there first emerged an organism with more information in its brain than in its genes. While Sagan refers this organism to be an early reptile, conflicting theories exist today in contention of this statement, and our earliest ancestor.

In conclusion, the evolution of the brain is a symbolic event in the history of life. The consequent bursts of brain evolution would result in the emergence of mammals, and of manlike primates. Nevertheless, there still remains much to the story.

“Mankind is poised midway between the gods and the beasts.”- Plotinus

As we will see in the following chapters, humankind’s naivety rests in its pride as the summit of the biological cycle, but while our authority on this Earth may be justified by the repeated insistence of our higher intelligence, and brain function, we are yet to realize that we are not so completely removed from the “beasts” themselves.

“…with all these exalted powers- Man still bears in his bodily frame the indelible stamp of his lowly origin.” – Charles Darwin, The Descent of Man