Charles Darwin, a great biologist and philosopher, offered a scientific and secular explanation of the process of human evolution and challenged the traditional religious beliefs of his time. His ideas were so provocative that they were either completely rejected or seriously challenged by the clergy, the traditional organizations, and the conservative institutions of the nineteenth century. While Darwin’s admirers and followers got involved in bitter public debates with the representatives of the church, Darwin quietly did his scientific work and continued to light the candles of science and reason in the dark alleys of blind faith.
In the last couple of centuries there has been an increasing awareness of his biological theories but still his psychological and sociological theories about human evolution have remained relatively unnoticed. Maybe that is why his book The Origin of Species, that focused on the biological dimension of evolution, is discussed far more than his book The Descent of Man. The latter book, published in 1881, the year before his death, discussed his psychosocial theories of evolution.
As a student of human psychology and a practicing psychotherapist, I am amazed at the insights Darwin had about the evolution of the human mind. He wanted to show that the human brain, like the human body, had also evolved from the lower animals, and that the observations of animal behavior can help us understand the similarities and differences between human and animal minds, especially those of mammals. While comparing humans to animals Darwin shared his observation that “the embryo of man closely resembles that of other mammals” (Descent, p. 9) that is why when we compare the human body with the bodies of animals we see striking similarities. Since the brain is one of the bodily organs, the human brain is in many ways similar to the brains of mammals. Quoting Bischoff, Darwin stated, “the convolutions of the brain in a human fetus at the end of the seventh month reach about the same stage of development as in a baboon when adult.” (Descent, p. 11) Because of such similarities humans share many mental functions with animals.
Darwin’s theory brought to the surface the hidden conflicts between religious, spiritual and secular traditions, and started a passionate public dialogue that is still going on between religious and secular circles. Darwin tried to prove that humans are risen apes rather than fallen angels. He inspired us to review our understanding of the human brain and mind.
There was a time when the human psyche was believed to be the soul. Religious people believed that the soul was independent and existed prior to the existence of the body. It entered the human fetus at a certain stage of development, stayed in the body throughout life, and left at the time of death to go back to the world of souls so that it could be judged on the Day of Judgment, thereby entering hell or heaven depending on its good and bad deeds. Such a concept of soul was predominant in Christian, Jewish and Muslim communities.
Alongside this “Juda-o-Christian-o-Islamic” belief in soul, there were many Hindus who followed the tradition of reincarnation and believed that the human soul returned to earth again and again to purify itself, and acquire a higher or lower level of existence depending upon good and bad deeds, the karma of the previous incarnation. This cycle of existence and suffering continued until the soul acquired enlightenment and found nirvana, and then transcended the cycle of suffering by joining the Ultimate Soul, God. After acquiring nirvana, the soul found eternal life and did not have to return to earth for any more suffering.
In these models, religious as well as spiritual, there was a desire, a wish, a hope, and a dream, for humans to have eternal life and live forever. Since the human body was mortal, human beings believed in the immortal soul, and connected that belief with the belief of an immortal and eternal God.
Darwin’s theory presented a secular model. Followers of such a model call the psyche, “mind,” not “soul.” In this model, the mind is intimately connected with the body and does not exist independent of the body. It is an extension of the body, related to the functioning of the brain, and is connected with the human personality that makes choices about the human lifestyle. Secular psychologists and psychiatrists now believe that the human mind and its illnesses can be understood in the light of the dynamic interaction between biological, psychological and social factors.
In The Descent of Man, Darwin had a special chapter titled “Comparison of the Mental Powers of Man and the lower mammals” in which he showed that “there is no fundamental difference in man and the higher mammals in their mental functions.” (Descent, p. 70) Darwin gave a series of examples from the animal kingdom to prove his point. He discussed animal behaviors that reflect how animals express their feelings from the basic to very complex emotions similar to humans. In the world of emotions being happy and enjoying life are some of the basic emotions experienced in playful behaviors. Similar to human children that like to play when they are healthy and happy, animal children also play and even fight, but that fighting is play fighting in which they pretend to bite but do not really bite. We see such playful behavior quite frequently in puppies. (Descent, p. 70)
Alongside the happy feelings, animals also have unhappy feelings whether of fear or of sadness. The fear response is the fight/flight response triggered when the animal is in danger. This response is similar in animals and humans “causing the muscles to tremble, the heart to palpitate, the sphincters to be relaxed, and the hair to stand on end.” (Descent, p. 70) In humans we see this clinical picture when people are anxious, have a stress response, or experience panic attacks. Like humans, animals not only feel sad when their dear ones die but also look after the young ones who are left behind. Darwin wrote, “So intense is the grief of female monkeys for the loss of their young that it invariably caused the death of certain kinds kept under confinement by Brehm in N. Africa. Orphan monkeys were always adopted and carefully guarded by the other monkeys, both males and females.” (Descent, p. 72)
Alongside happy and unhappy, painful and pleasurable feelings, Darwin believed that animals had a sense of wonder and curiosity–even a sense of humor. (Descent, p. 73) One of the feelings that humans are very proud of is the feeling of love. Darwin’s observations showed that animals are not only able to love but also want to be loved. He wrote, “Every one has seen how jealous a dog is of his master’s affection, if lavished on any other creature; and I have observed the same fact with monkeys. This shows that animals not only love, but have desire to be loved.” (Descent, p. 72)
Many people feel that animals might have primitive emotions but may not have a sense of reasoning or imagination, which they attribute only to humans. But Darwin even challenged that notion and proved that animals have those faculties. He cited an example of “… a monkey, which had weak teeth, used to break open nuts with a stone.” (Descent, p. 84)
Darwin also talked about the sense of beauty and aesthetics, and showed that animals express their taste for colors when they are selecting their mates. He wrote, “With the great majority of animals, however, the taste for the beautiful is confined, as far as we can judge, to the attractions of the opposite sex.” (Descent, p. 95) Darwin believed that the sense of aesthetics has developed far more in evolved human beings, and because of it they are able to appreciate nature, poetry and fine arts.
One main reason for such a development in humans is the development of cultures and languages, and the ability to write. Animals are able to communicate with each other but it is through nonverbal communication; they are not able to write. Because of written language humans have been able to advance in the disciplines of literature, science, psychology and philosophy.
After comparing the mental faculties of animals and humans Darwin also highlighted those faculties that are not fully grown in animals. He stated that humans have developed a concept of God and religions as part of their cultures. Darwin believed that the concept of God was not universal as there is no word for God in some languages. He wrote, “… numerous races have existed, and still exist, who have no idea of one or more gods, and who have no words in their languages to express such an idea.” (Descent, p. 97) On the other hand, he believed the concept of religion is universal. “… we include under the term ‘religion’ the belief in unseen or spiritual agencies … for this belief seems to be universal with the less civilized races.” (Descent, p. 97)
Darwin associated the development of religion with the experience of dreams and the concept of spirits. Rather than considering dreams as the functioning of the unconscious mind, many humans explain their dreams as if they are visited by the spirits of their dead relatives. After humans developed such superstitious beliefs they were passed on to the future generations as blind faith. The less-evolved humans accepted those superstitions and beliefs without questioning them. In some cases it had tragic results because some religious leaders demanded sacrifices and told their followers that the gods were angry, and to please them humans gave them money and food–even their own lives. Darwin realized that such simple-minded, naive, gullible and less-evolved humans were exploited and abused by their religious leaders, who gained political powers over a period of time.
Darwin was optimistic that, as science, psychology and philosophy would evolve, humans would learn to think rationally and logically, and then question the false beliefs of their parents, teachers and religious leaders. He commented on those customs, traditions and superstitions in these words, “Many of these are terrible to think of … such as the sacrifice of human beings to a blood-loving god; the trial of innocent persons by the ordeal of poison or fire; witchcraft, etc.–yet it is well occasionally to reflect on these superstitions; for they show us what an infinite debt of gratitude we owe to the improvement of our reason, to science, and our accumulated knowledge.” (Descent, p. 99)
Darwin shared that as the human mind evolved it also developed a sense of ethics and conscience. Humans developed a sense of empathy, and realized that their future growth, development and evolution are connected with the growth of other communities and cultures. He also recognized that alongside humans with evolved minds there are those humans that regress and then act as insensitive, inhumane, even cruel people. Darwin believed that such men and women had deranged minds. He wrote, “The same fact is likewise shown by the perversion or destruction of the moral sense being often one of the earliest symptoms of mental derangement.” (Descent, p. 128)
While Darwin showed the similarities between animal and human minds, he also brought to our attention how humans have evolved from animals and developed new skills: “nevertheless the difference in mind between man and higher animals, great as it is, certainly is one of degree and not of kind.” (Descent, p. 130)
Darwin highlighted in his writings that for human evolution to continue, human beings need to develop those characteristics that will be beneficial not only to individual persons but also for the whole species. In animals, changes and adaptations happened through natural selection and mutation, and were controlled by instinctual and unconscious factors. However, in humans those changes will depend upon individual and collective choices that are more conscious, rational and logical, since humans have the choice to follow or not to follow their instincts and are free to make wise choices. In addition, Darwin focused on how human beings’ selection of sexual partners from diverse social groups and cultural backgrounds also plays a significant role in deciding the future of the human species.
Darwin’s books and theories provided a solid foundation for the philosophies of naturalism, humanism, and secular psychology. Based on those foundations, other secular psychologists and philosophers such as Sigmund Freud, Karl Marx, Abraham Maslow, Jean Paul Sartre, Eric Fromm and many others erected tall buildings of secular psychology and philosophy. In the last century a number of psychological, sociological and humanistic theories about the human mind and personality became popular in mental health circles, and gave birth to the disciplines of psychiatry and psychotherapy. As time passes we become more and more aware of the contributions of Charles Darwin, not only in the world of biology but also in the disciplines of psychology and sociology. Darwin’s book The Descent of Man is a goldmine of understanding, not only about the similarities and differences between animal and human minds but also about the different stages of the evolution of the human mind.
 Darwin, Charles: The Descent of Man,
Great Mind Series, Prometheus Books, Amherst, New York, 1998.
 Bischoff, Theodor Ludwig Wilhelm (1807-1882), German embryologist and comparative anatomist. Bischoff was a strong opponent of Darwinism, although he admitted the many similarities between various embryos.
 Although Darwin did not mention the full name in his book, I am confident that this is the German zoologist, Alfred Edmund Brehm (1829-1884).