My father didn't care about books, folded corners, crossed lines, took notes, and sometimes got up and wrote many pages, not vomiting or being unhappy. His handwriting was scribbled, scribbled and altered, and Chen Siping put a lot of effort into identifying and transcribing it, which was time-consuming and laborious, but also quite accomplished.

One of them talks about "can't keep your mouth shut", which has a beginning and an end, which is very interesting.

"Can't control your mouth, heavy oil, heavy salt, heavy sugar, like to eat meat, overeating, this is probably a common problem of modern people's diet. Eating too much is not good for health, and only a few are strong-willed, and we constantly struggle against desires, and we always end up failing. Obviously, such a diet is harmful to health, why do you like to eat and think it is so delicious? Is it really a physical need?

"Today's food is extremely abundant, everything is available, in the history of human evolution is only a short moment, for a long time in the past, oil, salt, sugar, meat and even food itself are extremely scarce, for our ancestors, hunger and a full meal is the norm, feel delicious, eat more when you can, such traits are passed on to future generations through genes, and still affect our eating habits. Why does natural selection leave such genes?

"Creatures in nature do not die of old age, they are already 'dead' before they are 'old'. The same is true for humans. As a result, traits that are conducive to reproduction, even with even the slightest promotion, can quickly spread through the population and become dominant. In other words, genes that are conducive to reproduction are preserved, even if the gene causes the individual to suffer or die early, and genes that are not conducive to reproduction are removed, even if the gene makes the individual happy or long-lived.

"Parents who consume too much oil, salt, sugar and meat are worried about old age, or even survive old age, but it helps to reproduce strong offspring and take advantage of the next round of reproductive competition. And those parents who are 'modest' may live longer in old age, but they are at a relative disadvantage in terms of the quantity and quality of childbearing. 'Excessive' and 'moderation' are both traits of gene expression, and it is clear which gene will remain and become dominant traits in a population in a harsh natural environment.

"Human beings were once the carriers of genes, it doesn't matter whether they live long or not, happy or not, natural selection retains all genes that are conducive to reproduction, passes the peak of fertility, raises children, and the individual loses the value of existence, and it may be a better choice to die as soon as possible to make room for food and space for offspring.

"When the human species enters the modern era of 'civilization', with the abundance of food, medical advances, the effectiveness of natural selection is greatly weakened, we no longer have enough offspring, we no longer eliminate inferior individuals, except for those children who die young, almost all individuals can find mates, reproduce, and even solve the unsolved problems of the past through means such as fetal protection and artificial insemination, which is unimaginable in the natural environment.

"Social and cultural selection replaces natural selection, but social and cultural selection is different from natural selection, which selects genes and traits that are conducive to reproduction, while the former, in a sense, does not screen genes and traits. Human evolution has always been stagnant, and our current changes are more rooted in the accumulation of knowledge and the inheritance of culture, and have nothing to do with genes.

"Natural selection has lasted for a long time, social and cultural selection has only experienced a limited number of generations, in our bodies, the traits of gene expression are still the product of hundreds of thousands of years of natural selection, those unfavorable eating habits have provided reproductive advantages in the past when food was extremely scarce, but in today's extremely abundant and readily available food, oil, salt, sugar, and meat have become accomplices of disease, killers of health and longevity.

"Our bodies haven't 'adapted' to such changes, and we can't 'adapt'. It's not 'the fault of 'keeping your mouth shut'. ”

There is also an article about "heredity", which Chen Siping read shockingly.

"Heredity is very important, 'dragons give birth to dragons, phoenixes give birth to phoenixes', and heredity is uncertain, 'dragons give birth to nine sons, all different'. At a parent-teacher conference, I heard someone complaining, 'I was good at math when I was in school, and this kid is not like me at all.'" ’

"'This boy' refers to his son.

"The son is not good in mathematics, unlike Lao Tzu, leaving aside the acquired education and the chance of exams, in terms of genetics, whether a trait (such as "good at mathematics") can be reflected in the offspring involves many complex factors.

"The first thing to consider is whether a specific trait is genetically inherited. For example, the offspring of a one-armed man is not one-armed, because the 'one-armed' trait is not genetically expressed and cannot be inherited, and the offspring of a one-armed man remains fully limbed.

Second, assuming that a trait is genetically inherited, the parents do not necessarily pass on a particular trait to their offspring. Hermaphroditic reproduction is not parthenogenesis, and genetic recombination during meiosis and chromosomal combinations during zygotic formation will result in alterations, intensification, or weakening of certain traits. Human appearance is a good example, despite the urgent desire, we still can't be artificially 'meritorious', and the offspring of handsome men and beautiful women grow well, it is a matter of probability, not necessity.

"As another example, the causative gene is recessive hemophilia, citing a passage to illustrate the problem: 'Hemophilia A, i.e., factor VIII. procoagulant deficiency, is a sex-linked recessive genetic disorder, passed by females and males, and the genes synthesized by factor VIII procoagulant are located on the X chromosome. The diseased male is married to a normal female, and the male is normal among the children, and the female is the transmitter; A normal male is married to a female communicator, and half of the children are males and half females are transmitters; The male of the patient is married to the female of the transmitter, and half of the children are males, half of the females are patients, and half are transmitters. ’

"Thirdly, assuming that a certain trait is genetically inherited, and assuming that the parent inherits a particular trait to the offspring, the last question is, is the offspring's trait favorable to the environment? Obviously, a mathematical genius of the style of Chen Jingrun did not have much advantage in the living environment of Peking Man 500,000 years ago, and it may be more advantageous to have a strong physique and developed limbs.

"Why is it that every generation of a big family in history has seen the emergence of outstanding figures? Genetics, heredity, education, and opportunity are important factors, but what is easy to overlook is that they have enough children. Don't just give birth to one, give birth to more, and have children with different members of the opposite sex, in order to increase the probability of future generations being brilliant. ”

Chen Siping felt that his father meant something, he was dissatisfied with his mother and dissatisfied with himself. Such dissatisfaction, expressed in a tortuous and euphemistic, seemingly objective way, is left in the sky and between the lines. In his depression, he couldn't help but think of his mother, her temper and her way of life, and he found that he could not condemn his father.