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

by Carl Sagan

These mutations occur at random and are almost uniformly harmful—it is rare that a precision machine is improved by a random change in the instructions for making it.

This surely means that there is a part of our brain which remembers sounds and images, but not thoughts. I wonder if that sort of memory arose before we had very many thoughts—when it was important to remember the hiss of an attacking reptile or the shadow of a plummeting hawk, but not our own occasional philosophical reflections.

Childbirth is painful because the evolution of the human skull has been spectacularly fast and recent.

The incomplete closure of the skull at birth, the fontanelle, is very likely an imperfect accommodation to this recent brain evolution.

“Much of what we think of as human evolved long after the use of tools. It is probably more correct to think of much of our structure as the result of culture than it is to think of men anatomically like ourselves slowly developing culture.”

Why should an animal that has evolved from a reptile have to dream while other animals do not?

(Incidentally, the time taken for dream events has been shown by Dement to be approximately equal to the time the same events would have taken in real life.)

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.

In my view, the human condition would be greatly improved if such confrontations and willingness to reject hypotheses were a regular part of our social, political, economic, religious and cultural lives.

In general, human societies are not innovative. They are hierarchical and ritualistic. Suggestions for change are greeted with suspicion: they imply an unpleasant future variation in ritual and hierarchy: an exchange of one set of rituals for another, or perhaps for a less structured society with fewer rituals. And yet there are times when societies must change. “The dogmas of the quiet past are inadequate for the stormy present” was Abraham Lincoln’s description of this truth.

Russell commented that the development of such gifted individuals required a childhood period in which there was little or no pressure for conformity, a time in which the child could develop and pursue his or her own interests no matter how unusual or bizarre.

I sometimes wonder whether the appeal of sex and aggression in contemporary American television and film offerings reflects the fact that the R-complex is well developed in all of us, while many neocortical functions are, partly because of the repressive nature of schools and societies, more rarely expressed, less familiar and insufficiently treasured.

Unless we destroy ourselves utterly, the future belongs to those societies that, while not ignoring the reptilian and mammalian parts of our being, enable the characteristically human components of our nature to flourish; to those societies that encourage diversity rather than conformity; to those societies willing to invest resources in a variety of social, political, economic and cultural experiments, and prepared to sacrifice short-term advantage for long-term benefit; to those societies that treat new ideas as delicate, fragile and immensely valuable pathways to the future.

Dartmouth’s preeminence in this innovation is related to the fact that its president, John G. Kemeny, is a distinguished computer scientist and the inventor of a very simple computer language called BASIC.

The array of possible courses of computer interactive learning is limited only by the ingenuity of the programmers, and that is a well that runs very deep.

Since our society is so profoundly influenced by science and technology, which the bulk of our citizens understand poorly or not at all, the widespread availability in both schools and homes of inexpensive interactive computer facilities could just possibly play an important role in the continuance of our civilization.

In our modern world, illiterates have a different sense of direction, a different sense of self-reliance, and a different sense of reality.

The improvement in human knowledge and survival potential following the invention of writing was immense.

When all is said and done, the invention of writing must be reckoned not only as a brilliant innovation but as a surpassing good for humanity.

Gravity, quantum mechanics, and the great bulk of physics and chemistry are observed to be the same elsewhere as here.

Natural selection has served as a kind of intellectual sieve, producing brains and intelligences increasingly competent to deal with the laws of nature.

The Mormyrid has developed a special organ which establishes an electric field and monitors that field for any creatures traversing it.

Without vigorous, farsighted and continuing encouragement of fundamental scientific research, we are in the position of eating our seed corn: we may fend off starvation for one more winter, but we have removed the last hope of surviving the following winter.

The time of Augustine’s death, 430 A.D., marks the beginning of the Dark Ages in Europe.

and the doctrine of the special creation, by God or gods, of mankind despite our deep relatedness, both in biochemistry and in brain physiology, with the other animals.