On Human Nature

1. Human Nature: A Biological Tapestry, Not a Blank Slate

If the brain is a machine of ten billion nerve cells and the mind can somehow be explained as the summed activity of a finite number of chemical and electrical reactions, boundaries limit the human prospect—we are biological and our souls cannot fly free.

Biological Basis. The human mind, with all its complexity, is not a blank slate but a product of biological processes. Our brains, composed of billions of nerve cells, operate through chemical and electrical reactions, placing limits on our potential and highlighting our biological nature. This perspective challenges the idea that culture alone shapes human behavior.

Evolutionary Roots. Our species evolved through Darwinian natural selection, meaning that genetic chance and environmental necessity, not divine intervention, shaped us. This understanding is crucial for any serious consideration of the human condition. It suggests that our minds are not designed to understand everything, but rather to promote the survival and reproduction of our genes.

Implications for Understanding. Recognizing our biological basis allows us to approach human nature as an object of empirical research. This approach can enrich our self-conception and provide a more truthful understanding of our actions and motivations. It also implies that the humanities and social sciences are limited descriptors of surface phenomena without this biological foundation.

2. Genes and Culture: A Dance of Influence, Not a Dictatorship

The question of interest is no longer whether human social behavior is genetically determined; it is to what extent.

Interaction, Not Determination. Human behavior is not solely determined by genes, nor is it solely a product of culture. Instead, it is the result of a complex interaction between our genetic predispositions and our environment, especially our cultural environment. This interaction shapes each individual.

Genetic Constraints. While culture is a powerful force, it is not all-powerful. Human social behavior, when compared to other species, is limited and idiosyncratic. Certain traits, like our social group size and the long period of social training for the young, are shared with other primates, suggesting a genetic influence.

Cultural Universals. Despite the diversity of cultures, there are universal traits that appear in every society, such as age-grading, cooking, language, and marriage. These universals suggest that human nature is not infinitely malleable but is constrained by our biological heritage. This is not to say that culture is unimportant, but that it operates within the boundaries set by our genes.

3. Development: A Landscape of Possibilities, Not a Single Path

Rather than specify a single trait, human genes prescribe the capacity to develop a certain array of traits.

Capacity, Not Predestination. Our genes do not dictate a single, predetermined path of development. Instead, they provide us with the capacity to develop a range of traits. The specific traits that emerge depend on the interaction between our genes and our environment.

Developmental Channels. The development of a trait can be visualized as a ball rolling down a landscape with ridges and valleys. Some traits, like eye color, have deep, unbranching channels, while others, like language, have a broad network of channels that can be influenced by experience. This metaphor highlights the interplay between genetic predispositions and environmental factors.

Prepared Learning. Human learning is not an all-purpose phenomenon. We are predisposed to learn certain things more easily than others. For example, we are more likely to develop phobias of snakes and spiders than of modern artifacts like knives or guns. This "prepared learning" suggests that our brains are wired to prioritize certain types of information.

4. Aggression: A Spectrum of Responses, Not a Singular Instinct

The answer to it is yes. Throughout history, warfare, representing only the most organized technique of aggression, has been endemic to every form of society, from hunter-gatherer bands to industrial states.

Not a Single Drive. Human aggression is not a single, monolithic instinct but a spectrum of responses, each with its own triggers and controls. These responses include territorial defense, dominance assertion, sexual aggression, and moralistic aggression.

Environmental Influence. While we have a genetic predisposition towards aggression, its expression is heavily influenced by environmental factors. Crowding, competition for resources, and cultural norms all play a role in shaping aggressive behavior. The most peaceable tribes of today were often the ravagers of yesteryear, demonstrating the plasticity of human aggression.

Culture and Learning. Aggression is not simply a release of pent-up energy but a learned behavior. The culture-pattern model suggests that the practice of war is accompanied by an increase in other forms of aggression, such as combative sports. This highlights the role of learning and cultural norms in shaping our aggressive tendencies.

5. Sex: Beyond Reproduction, a Force for Bonding and Diversity

The essence of the argument, then, is that the brain exists because it promotes the survival and multiplication of the genes that direct its assembly.

More Than Procreation. Sex is not primarily for reproduction but for creating diversity. Sexual reproduction mixes genes, providing a hedge against environmental change. This diversity is crucial for the long-term survival of a species.

Gamete Dimorphism. The difference in size and investment between eggs and sperm has profound consequences for sexual behavior. Females invest more in each offspring, leading to greater selectivity in mate choice, while males are more competitive and less discriminating.

Bonding and Pleasure. Human sexuality is characterized by continuous receptivity and a focus on pleasure, which serves to strengthen pair bonds. This emphasis on bonding, rather than just reproduction, is a key feature of human sexual behavior. This is why the sexual bond transcends sexual activity.

6. Altruism: Self-Interest in Disguise, Yet Capable of Greatness

If that perception is correct, science may soon be in a position to investigate the very origin and meaning of human values, from which all ethical pronouncements and much of political practice flow.

Two Forms of Altruism. Human altruism comes in two forms: "hard-core" altruism, which is directed towards close relatives and is often unconscious, and "soft-core" altruism, which is ultimately self-serving and based on the expectation of reciprocation.

Kin Selection. Hard-core altruism is likely to have evolved through kin selection, where individuals favor the survival and reproduction of relatives who share their genes. This explains why we are more likely to sacrifice for family than for strangers.

Reciprocity and Self-Interest. Soft-core altruism is driven by self-interest and the expectation of reciprocation. This form of altruism is essential for building complex societies, as it allows for cooperation among unrelated individuals. The capacity for soft-core altruism is deeply influenced by cultural evolution.

7. Religion: A Powerful Force, Rooted in Biology and Culture

The predisposition to religious belief is the most complex and powerful force in the human mind and in all probability an ineradicable part of human nature.

Universal Phenomenon. Religious belief is a universal human trait, found in every society from hunter-gatherers to modern nations. It is a powerful force that shapes our values, behaviors, and social structures.

Biological Basis. The predisposition to religious belief is likely rooted in our biology. Our brains are wired to seek meaning, create narratives, and form strong group allegiances. These predispositions make us susceptible to religious ideas and practices.

Cultural Evolution. While the predisposition to religion may be biological, the specific forms that religion takes are shaped by cultural evolution. Religions evolve to enhance the welfare of their practitioners, often through a combination of altruism and exploitation. This is why religions are often intolerant of other religions.

8. The Evolutionary Epic: A New Mythology for a Scientific Age

I suggest that the evolutionary epic is probably the best myth we will ever have.

Scientific Materialism as Mythology. Scientific materialism, with its emphasis on the evolutionary epic, can serve as a new mythology for a scientific age. This mythology, based on the laws of physics and biology, can provide a framework for understanding our place in the universe.

Reconciling Science and the Humanities. The key to bridging the gap between science and the humanities lies in recognizing that the human mind is a product of evolution. By understanding the biological basis of our thoughts, emotions, and behaviors, we can create a more unified view of human existence.

The Future of Human Nature. As we gain a deeper understanding of our biology, we will be faced with the choice of whether to alter our own nature. This choice will require a careful consideration of our values and a willingness to embrace the full complexity of the human condition.

Last updated: January 24, 2025