Some people have unhealthy stomachs; some have small stomachs; some have slightly misshapen stomachs. But the differences are tiny compared with the similarities. A vet or a butcher could teach the surgeon about a much greater variety of different stomachs: big, multichambered cow stomachs; tiny mouse stomachs; somewhat human looking pig stomachs. There is, it is safe to say, such a thing as the typical human stomach, and it is different from a nonhuman stomach.
It is the assumption of this book that there is also, in the same way, a typical human nature. It is the aim of this book to seek it: Like the stomach surgeon, a psychiatrist can make all sorts of basic assumptions when a patient lies down on the couch. He can assume that the patient knows what it means to love, to envy, to trust, to think, to speak, to fear, to smile, to bargain, to covet, to dream, to remember, to sing, to quarrel, to lie. Even if the person were from a newly discovered continent, all sorts of assumptions about his or her mind and nature would still be valid. When, in the 1930s , contact was made with New Guinea tribes hitherto cut off from the outside world and ignorant of its existence, they were found to smile and frown as unambiguously as any Westerner, despite 100,000 years of separation since
mon ancestor: The 'smile' of a baboon is a threat; the smile of a man is a sign of pleasure: It is human nature the world over: That is not to deny the fact of culture shock. Sheeps ' eye-ball soup, a shake of the head that means yes, Western privacy, circumcision rituals, afternoon siestas, religions, languages, the difference in smiling frequency between a Russian and an American waiter in a restaurant—there are myriad human particulars as well as human universals: Indeed, there is a whole discipline, cultural anthropology, that devotes itself to the study of human cultural differences. But it is easy to take for granted the bedrock of similarity that underlies the human race—the shared peculiarities of being human.
This book is an inquiry into the nature of that human nature: Its theme is that it is impossible to understand human nature without understanding how it evolved, and it is impossible to understand how it evolved without understanding how human sexuality evolved. For the central theme of our evolution has been sexual.
Why sex? Surely there are features of human nature other than this one overexposed and troublesome procreative pastime: True enough, but reproduction is the sole goal for which human beings are designed; everything else is a means to that end: Human beings inherit tendencies to survive, to eat, to think, to speak, and so on: But above all they inherit a tendency to reproduce: Those of their predecessors that reproduced passed on their characteristics to their offspring; those that remained barren did not: Therefore, anything that increased the chances of a person reproducing successfully was passed on at the expense of anything else. We can confidently assert that there is nothing in our natures that was not carefully 'chosen' in this way for its ability to contribute to eventual reproductive success:
This seems an astonishingly hubristic claim: It seems to deny free will, ignore those who choose chastity, and portray human beings as programmed robots bent only on procreation: It seems to imply that Mozart and Shakespeare were motivated only by sex: Yet I know of no other way that human nature can have HUMAN NATURE
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developed except by evolution, and there is now overwhelming evidence that there is no other way for evolution to work except by competitive reproduction. Those strains that reproduce persist; those that do not reproduce die out. The ability to reproduce is what makes living things different from rocks: Besides, there is nothing inconsistent with free will or even chastity in this view of life. Human beings, I believe, thrive according to their ability to take initiatives and exercise individual talent: But free will was not created for fun; there was a reason that evolution handed our ancestors the ability to take initiatives, and the reason was that free will and initiative are means to satisfy ambition, to compete with fellow human beings, to deal with life 's emergencies, and so eventually to be in a better position to reproduce and rear children than human beings who do not reproduce. Therefore, free will itself is any good only to the extent that it contributes to eventual reproduction.
Look at it another way: If a student is brilliant but terrible in examinations—if, say, she simply collapses with nervousness at the
nothing in a course that 'is tested by a single examination at the end of the term. Likewise, if an animal is brilliant at survival, has an efficient metabolism, resists all diseases, learns faster than its competitors, and lives to a ripe old age, but is infertile, then its superior genes are simply not available to its descendants. Everything can be inherited except sterility. None of your direct ancestors died childless. Consequently, if we are to understand how human nature evolved, the very core of our inquiry must be reproduction, for reproductive success is the examination that all human genes must pass if they are not to be squeezed out by natural selection: Hence I am going to argue that there are very few features of the human psyche and nature that can be understood without reference to reproduction: I begin with sexuality itself. Reproduction is not synonymous with sex; there are many asexual ways to reproduce. But reproducing sexually must improve an individual 's reproductive success or else sex would not persist: I end with intelligence, the most human of all features. It is increasingly hard to
understand how human beings came to be so clever without considering sexual competition.
What was the secret that the serpent told Eve? That she could eat a certain fruit? Pah. That was a euphemism. The fruit was carnal knowledge, and everybody from Thomas Aquinas to Milton knew it. How did they know it? Nowhere in Genesis is there even the merest hint of the equation: Forbidden fruit equals sin equals sex. We know it to be true because there can only be one thing so central to mankind. Sex.
OF NATURE AND NURTURE
The idea that we were designed by our past was the principal insight of Charles Darwin. He was the first to realize that you can abandon divine creation of species without abandoning the argument from design. Every living thing is 'designed ' quite unconsciously by the selective reproduction of its own ancestors to suit a particular life- style. Human nature was as carefully designed by natural selection for the use of a social, bipedal, originally African ape as human stomachs were designed for the use of an omnivorous African ape with a taste for meat.
That starting point will already have irritated two kinds of people. To those who believe that the world was made in seven days by a man with a long beard and that therefore human nature cannot have been designed by selection but by an Intelligence, I merely bid a respectful good day. We have little common ground on which to argue because I share few of your assumptions. As for those who protest that human nature did not evolve, but was invented
