Published in the Philosophical Review, 2019

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Was there any hidden ‘intention’ in the process of evolution? Or was it just a passive adaptation to objective forces of Natural Selection?

For more than a century, the focus in debates about Darwin’s work was about natural selection, as presented in his first book On the Origin of Species.  The book created an earthquake in the domain of humanity’s thoughts about its origin, and the following aftershocks clouded what Darwin had to say in his second book The Descent of Man, and Selection in Relation to Sex.

It was so difficult for people during the conservative atmosphere of the 19th century to accept even natural selection, let alone to consider another mechanism of evolution in which sexual selection was suggested.  It took about one hundred years for evolutionary biologists to seriously consider ‘mate choice’ as a genuine mechanism in the process of evolution.

Sexual selection – purposeful choice in the process of mating – is the very vehicle for delivering genes to future generations.  Subjective attraction of involved individuals brought to reproduction a dimension of intentional preference.  Delivery of genes to a future generation became conditioned by an inwardly driven direction, in which subjective attraction and awareness of individuals played a decisive role.

In his recent (2017) book, The Evolution of Beauty, Professor Richard Prum presents a detailed analysis of the power of sexual attraction, and its effect on future generations of species:

“… animals can play a distinct and vital role in their own evolution through their sexual and social choices”. (Prum 2017:27).

This means that the destiny of the next generation has been impacted by females' selectivity in the process of ‘mate choice:

“In Descent [of Man] Darwin presented his hypothesis that female sexual autonomy – the taste for the beautiful – is an independent transformative evolutionary force in the history of life”. (Prum 2017:28).

Aesthetic features in animals, birds in particular (such as colours, singing, dancing, etc.), were signs of healthy traits and strength in males, which females valued as important features to pass on to their young:

“But Darwin observed that in many of the most highly ornamented species the evolutionary force of sexual selection acted predominantly through female mate choice, which is why this book focuses largely on female mate choice. If female aesthetic preferences drove the process, then female sexual desire was responsible for creating, defining, and shaping the most extreme forms of sexual display that we see in nature.

Ultimately, it is female sexual autonomy that is predominantly responsible for the evolution of natural beauty. […] So, sexual autonomy is the capacity for an individual organism to exercise an informed, independent, and uncoerced sexual choice about whom to mate with”. (Prum 2017:27-28).

It is not difficult to reason that, aware of their motherhood’s needs, early human females preferred males who were less aggressive and more caring, enabling them to pass their traits on to future generations. For mothers at the early stage of humanity, reducing the excessive violence dominant in the ancestry of apes was highly desirable:

“Human females transformed the nature of male social behaviour by evolving to agree that male traits associated with aggression and sexual coercion were not sexy”. (Prum 2017:295).

Through encouraging selected males to mate with them, females were seeking benefit for their future children and security for their motherhood:

"… female sexual autonomy results in lower costs of male sexual coercion to females; that is, greater infant survival, lower direct harm to females and enhanced population growth".  (Prum 2017:298).

Intention affecting the process of evolution of species

Intention is a drive acting within living organisms, reflecting their awareness and preference.  All living entities employ a conscious mental evaluation to distinguish that which is beneficial for their purpose of survival and reproduction from that which should be avoided.  This mental evaluation operates in the process of mate choice.

Consequently, intention creates an impact on the traits of the next generation.  To view the process of generational changes as a mere passive product of adaptation of organisms to external changes in the environment is a view that ignores the role of the mental aspect of the living organism: having preferences, memory, and a relevant degree of intellect. Sexual selection has a huge importance for females, as mating means many months of pregnancy, giving birth and later care – a quite lengthy and serious responsibility. Through mental awareness of what would work for their motherhood, females were empowered to influence mating for their own benefit, and this led to intentional and radical selectivity, which modulated the genes of future generations.

While the duration and depth of the role of motherhood varies in different species, it is the longest in primates and human beings, and it is also the deepest experience in terms of emotional bonds.  Morgana Diamantopoulos commented on the common traits they share with humans:

“Chimpanzees are capable of feeling a wide range of emotions, including joy, happiness and empathy. […] When a chimpanzee is feeling stressed or anxious, others will often groom or hug them for assurance.

One of the deepest bonds a chimpanzee will form is with its mother. During the first few years of life, a chimpanzee relies almost entirely on its mother for protection, nourishment and love”. (Diamantopoulos).

This observation of the power of motherhood is common to the two close species of chimpanzees and humans, who, according to evolutionary biologists, split from a common ancestor between 5 and 7 million years ago. Differently from apes, however, early human mothers must have realised that investing in motherhood within the unpredictable, ego-driven environment of male violence was for them just disastrous. Any male-male challenge for leadership in the group meant for mothers the mass killing of their children:

“... males of many primate species have evolved to create more reproductive opportunities for themselves by killing all the dependent offspring of females when they gain control of the group.

When a female dependent child is killed, the fact that she is no longer breastfeeding will cause her to go into estrus, at which point she will resume mating.   Infanticide is a selfish male solution of how to capitalise quickly on the advantages of having won the male-male competition. However, the results are devastating for the female reproductive success and for the population as a whole” . (Prum 2017:285).

Infanticide is widespread in ape communities, resulting in a very high rate of infant mortality. It is a spontaneous expression of male dominance, which early human mothers had to confront wisely, using their own sexual powers to make a shift from apelike to human behaviour:

“Human sexuality has made a sharp break with the sexual habits of our primate ancestors “.(Prum 2017:284).

Professor Prum correlates the start of humanity with extended childhood development, which required cooperative social behaviour, culture, language and other factors, which mothers instilled in their children. This intentional trend to reduce coercion and extend protection of the newly born has led to changes in the shape and morphology of the species:

“One major morphological trend in human evolution has been a reduction in sexual dimorphism in both body mass and canine tooth size [    ] Thus, the reduction in sexual dimorphism in the human lineage may reflect a transition from a more chimpanzee-like mating system, with high levels of male-male violence and sexual coercion of females, toward monogamy and cooperative breeding.

 This shift in social systems – which may have begun as early as 3 million y[ears] ago – likely favored an initial reduction in aggression and increased tolerance between individuals. Within the last 200,000 y[ears], additional changes in human craniofacial morphology raise the intriguing possibility of a second wave of selection against aggression that coincided with the emergence of behavioral modernity”. (MacLean 2016).

What made us human?

Despite the partial tendency for empathy within ape communities, a display of abhorrent aggression and brutality has been documented by various researchers. David Attenborough, Jane Goodall, Frans de Waal and others have provided a wealth of objective material about what dominates the ‘code of conduct’ in ape groups. Research into the chimpanzee norms of behaviour reveals a strong motivation for alpha male domination –

competition for leadership through physical force, beating the opponent to death, killing children, hatred towards neighbouring groups and waging wars of extermination with bizarre brutality:

“... the biologically similar chimpanzees live in patriarchal groups in which males regularly rape, beat, kill, and sometimes even drink the blood of their own kind “. (Pelton 1997).

In a stark contrast to apes, human behaviour is based on cooperation, self-control and reasoning about consequences, motivations which do not play any role in ape communities.  The transition to civilisation could not have occurred without the intentional efforts of early humans to subdue the violence and prejudice which opposes cooperation and empathy among different tribes, as Darwin observed in Descent of Man:

“As man advances in civilization, and small tribes are united into larger communities, the simplest reason would tell each individual that he ought to extend his social instincts and sympathies to all members of the same nation, though personally unknown to him. This point being once reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and races”. (Darwin 1871).

The intention of early humans to extend their empathy and cooperation among various tribes is what distinguished human evolution.  It created a shift from senseless violence and hatred towards other families or groups, and provided a huge evolutionary benefit of sharing tools, language and enhanced security.

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