First of all, the principle of human death lies in the aging of various organs, which cannot be compensated by itself. The main causes of death are cardiopulmonary system, cranial nerve system, gastrointestinal system and circulatory system. It can be said that many organ diseases will lead to death. The so-called death is generally marked by cardiac arrest, and some are marked by brain death. Of course, these are normal deaths and there are other accidents.
The aging of human organs is irreversible, not only human organs, but all organisms or biological organs that undertake functions are aging, because when they undertake functions, they consume oxygen and carbohydrates for oxidation, which will produce heat energy, and the continuous manufacture and accumulation of heat energy will produce catalysis, so that the constituent cells of the organs themselves will also participate in oxidation. Therefore, the function of an organ is realized by sacrificing a part of itself.
People have the ability to regenerate cells, so the loss of organs can be made up by cell regeneration and renewal, but brain cells cannot be regenerated, and organs that regenerate cells are also aging. When a sufficient number of new cells can't be provided, the loss of organs can't be made up, so the aging of the human body appears until the end.
So people's death is quantitative to qualitative, not sudden.
Of course, we should have the illusion that one day science and technology will be more developed, and we can understand the mystery of cell regeneration, which can delay aging and prolong life. What we are doing now does play this role, but because the human body is too complicated, the current medicine can't fully understand all the mysteries of life, so it can't fundamentally inhibit aging.
So you know, in many sci-fi movies, people can live for hundreds of years if they are frozen. There is a certain scientific basis. Low temperature can make organs stop working and not be oxidized or decomposed by bacteria. If you continue to work after you have recovered, people will be resurrected. I haven't heard of real experiments, but animal experiments have been done and there are indeed examples of resurrection. The rice seeds unearthed from Hemudu site in China 6000 years ago can still be planted, which is also an example of plants.
Of course, living like that has no practical significance, so just because we want to be awake, we have to consume organs and face aging and death. Therefore, how to face death is a very serious problem, and it is also a problem that human beings have been studying all the time. This is an ancient and profound discipline-philosophy.
The premise of philosophy is that people are bound to die, so the time to live is limited. How to treat death and how to treat this limited time constitute two major parts of philosophy.
The purpose of most philosophies is to make people optimistically accept the result of inevitable death, and find ways to make life more meaningful and ways to think about problems. All this is to convince yourself that there is a completely acceptable reason to continue to live and live better, and then face death optimistically, because living is also an unchangeable fact.
Therefore, most philosophies need to answer the questions of the world, heaven and earth, people and where people come from, because we have seen these. Philosophically, the highest level should be Taoism, which believes that everything is changing and the transformation of yin and yang is complementary. The only constant is change and the law of change, which is the so-called Tao. So people may be changed by foxes, so they are called foxes. Christianity believes in the existence of God and has made a contract with mankind. We do something for God, and God does something for us, because man is made by God. Buddhism believes that there are samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara, samsara. Many other religions, such as Judaism, believe that man is the son of the sun and the son of heaven, all of which explain the origin of man.
In short, philosophy hopes that we can be persuaded by ourselves, accept life, accept death, live better and die better optimistically. As a person, we should accept one of them, because living better and dying optimistically is indeed our goal.
Supplementary answer-
1. Methodology philosophy includes many theories, such as pragmatism, cynicism, materialism, objectivity and so on. They answered the methodology of how people face the world, not the source of people and the source of the world. Therefore, philosophy is divided into two parts: world outlook and methodology. The methodology part develops constantly, and new disciplines are constantly divided, such as psychology, logic and even mathematics, which originally belong to the category of philosophy. This paper discusses the world outlook, because problems are also world outlook, including religious world outlook; Religion is also divided into world outlook and methodology;
2. The conservation of energy has long been overthrown by Einstein, and the correct one should be the conservation of mass and energy;
3. Genetic theory studies aging from one angle, which cannot be said to be one-sided, but it is not comprehensive for this problem. The conservation and constant transformation of mass and energy is the main reason, including the universe and planets are controlled by this law, and they are constantly transforming, and there is no eternal matter. Similarly, thermonuclear fusion and fission widely exist in matter, which are the main laws of mass-energy conversion and constitute a cycle. The so-called oxidation belongs to generalized nuclear fusion from a microscopic point of view, and reduction belongs to nuclear fission. To put it simply.
In the end, all people can realize is the possibility of all truth. This is Socrates' famous saying and what I believe. With the deepening of understanding, there will always be new problems, which is also the mechanism of human intelligence development. Therefore, the transformation and conservation of mass and energy will be broken in the future. This is my call for idealism. If one day, matter will no longer transform, that is the premise that life will no longer decompose, and then people may not die. You know, human death is only the transformation of matter and energy.
Continue to supplement the answer-
There is no answer to the first question, because the premise of the question is uncertain, and you need to know all the stars to have an answer. If people can not die, the simplest thing is war, because birth control is difficult for everyone to abide by, and killing newborns is also against humanity;
So is the second one. The debate between a child and a fish is purely a debate game.
Fourthly, the transformation between mass and speed is Einstein's greatest discovery. When the speed of an object approaches the speed of light, its mass will increase and time will slow down. Matter does not preserve itself, and neither does energy.
Fifth, because I am not everything, I will not know everything, because I am one of everything, so I only know the truth at most; Of course, the premise of knowing is complete control and experience. Even if you control the experience, you still don't know.
Sixth, the ultimate evolution of life is transformation, from protein to a new organizational structure, just like from inorganic to organic, from organic to other; The existence of life is beautiful, because existence is the foundation of everything, and the subsequent beauty also has its own answers because of the different life forms, and there is no standard answer.
Seventh, God created man, but he also created God, because cats and dogs don't know this guy. Nietzsche thinks he is the sun because he thinks he can shine on the whole earth; I can also think of myself as God, if one day I think I can bless everyone.
Philosophical world outlook and methodology are interactive, that is to say, what kind of logic we use to understand and judge the right and wrong of unknown things directly affects our understanding of it. Among them, transcendental and explanatory methods are commonly used. It is very simple to falsify the conclusion, just find a disproof. The Book of Changes contains a lot of mathematical logic to assist the idea of "one divides into two", so a good world outlook inevitably needs a good methodology. Otherwise, all questions have no answers.