Sociobiology is not just any statement that biology, genetics, and evolutionary theory have something to do with human behavior. Sociobiology is a specific theory about the nature of genetic and evolutionary input into human behavior. It rests upon the view that natural selection is a virtually omnipotent architect, constructing organisms part by part as best solutions to problems of life in local environments. It fragments organisms into “traits,” explains their existence as a set of best solutions, and argues that each trait is a product of natural selection operating “for” the form or behavior in question. Applied to humans, it must view specific behaviors (not just general potentials) as adaptations built by natural selection and rooted in genetic determinants, for natural selection is a theory of genetic change. Thus, we are presented with unproved and unprovable speculations about the adaptive and genetic basis of specific human behaviors: why some (or all) people are aggressive, xenophobic, religious, acquisitive, or homosexual.

The study of human nature must have profound implications for the study of history, sociology, psychology, anthropology, and politics. Each of those disciplines is an attempt to understand human behavior, and if the underlying universals of human behavior are the product of evolution, then it is vitally important to understand what the evolutionary pressures were.

The starting point for evolutionary psychology is the idea that human beings are animals, and that like all animals, we’re products of natural selection. This is true of our bodies, but it’s also true of our minds.

Some people think that evolutionary psychology claims to have discovered that human nature is selfish and wicked. But they are flattering the researchers and anyone who would claim to have discovered the opposite. No one needs a scientist to measure whether humans are prone to knavery. The question has been answered in the history books, the newspapers, the ethnographic record, and the letters to Ann Landers. But people treat it like an open question, as if someday science might discover that it's all a bad dream and we will wake up to find that it is human nature to love one another.”

There is, therefore, such a thing as a universal human nature, common to all people.

The conclusion this article reaches, based on the presented arguments, is that Evolutionary Psychology (EP) may be a contribution to psychological science at several different, important levels. First, EP allows psychologists to communicate between different areas of psychological interest, and with other branches of science relevant to psychology as a life science. Second, EP provides a well-researched, rigorously formulated theory for evaluating any other psychological theory. The theory may prevent one from suggesting abilities that could not evolve but have been suggested within almost all psychological disciplines. The versatility EP shows as a theoretical framework for disciplines as different as psychoanalysis and cognitive science, suggests that EP may succeed in integrating psychological science. It also supports the claim that EP is as theoretically valid a science as cognitive science and evolutionary biology. EP also brings to psychology the focus on a theoretically rigorous and predictive theory of Human Nature, and the functional approach, which may provide maturation from the level of mere descriptive science. At the level of generating new theories and insights about Human Nature, EP seems to have proven its worth.

"There is no nature that exists devoid of nurture; there is no nurture that develops without nature. To say otherwise is like saying that the area of a field is determined by its length but not its width. Every behavior is the product of an instinct trained by experience.

The study of human beings remained resolutely unreformed by these ideas until a few years ago. Even now, most anthropologists and social scientists are firmly committed to the view that evolution has nothing to tell them. Human bodies are products of "culture," and human culture does not reflect human nature, but the reverse. This restricts social scientists to investigation only differences between cultures and between individuals — and to exaggerating them. Yet what is most interesting to me about human beings is the things that are the same, not what is different — things like grammatical language, hierarchy, romantic love, sexual jealousy, long-term bongs between the genders ("marriage", in a sense). These are trainable instincts peculiar to out species and are just as surely the products of evolution as eyes and thumbs."

Evolutionary psychology was the organizing framework—the source of “explanatory adequacy” or a “theory of the computation”—that the science of psychology had been missing. Like vision and language, our emotions and cognitive faculties are complex, useful, and nonrandomly organized, which means that they must be a product of the only physical process capable of generating complex, useful, nonrandom organization, namely, natural selection. An appeal to evolution was already implicit in the metatheoretical directives of Marr and Chomsky, with their appeal to the function of a mental faculty, and evolutionary psychology simply shows how to apply that logic to the rest of the mind.

To tell the story of a past so as to portray an inevitable destiny is, for humankind, a need as universal as tool-making. To that extent, we may say that a human being is, by nature, historicus.

The huge human brain, approximately 1,350 cubic centimeters, is the most complex organic structure in the known world. Understanding the human mind/brain mechanisms in evolutionary perspective is the goal of the new scientific discipline called evolutionary psychology. Evolutionary psychology focuses on four key questions: (1) Why is the mind designed the way it is—that is, what causal processes created, fashioned, or shaped the human mind into its current form? (2) How is the human mind designed—what are its mechanisms or component parts, and how are they organized? (3) What are the functions of the component parts and their organized structure—that is, what is the mind designed to do? (4) How does input from the current environment interact with the design of the human mind to produce observable behavior?

I speak about universal evolution and teleological evolution, because I think the process of evolution reflects the wisdom of nature. I see the need for wisdom to become operative. We need to try to put all of these things together in what I call an evolutionary philosophy of our time.

There is not one human nature. There is not some uniform and unchanging way that everybody is and how everybody sees the world. Human nature has different meanings in different times and for different classes and groups in society.

"We have been told over and over that "you can't change human nature", but the study of emic realities shows quite the contrary, that almost anything can become "human nature" if society defines it as such."

Understanding human nature must be the basis of any real improvement in human life. Science has done wonders in mastering the laws of the physical world, but our own nature is much less understood, as yet, than the nature of stars and electrons. When science learns to understand human nature, it will be able to bring a happiness into our lives which machines and the physical sciences have failed to create.