Death is the end of life, yet it is the most common event on Earth, claiming approximately 150,000 lives every single day. As of the early 21st century, 56 million people die per year, and an estimated total of almost 110 billion humans have died since the dawn of our species, representing roughly 94% of all humans to have ever lived. This overwhelming statistic defines the human condition, creating a silent majority that has passed into history while the living remain to witness the aftermath. The cause of death is usually considered important, and an autopsy can be done to determine it, but the most common reason is aging, which leads to cardiovascular disease, the disease that affects the heart or blood vessels. While some organisms, such as the immortal jellyfish, are biologically immortal, they can still die from means other than the effects of aging, proving that death is not always a biological inevitability but often a result of external forces or accidents.
Defining The Moment
Determining when a person has definitively died has proven difficult, as the cessation of life functions is often not simultaneous across organ systems. Initially, death was defined as occurring when breathing and the heartbeat ceased, a status still known as clinical death, but the development of cardiopulmonary resuscitation meant that such a state was no longer strictly irreversible. For all organisms with a brain, death can instead be focused on this organ, leading to the concept of brain death, which is sometimes used as a legal definition of death. Some people believe that all brain functions must cease, while others believe that even if the brainstem is still alive, the personality and identity are irretrievably lost, so therefore the person should be considered entirely dead. The category of brain death is seen as problematic by some scholars, such as Dr. Franklin Miller, a senior faculty member at the Department of Bioethics, National Institutes of Health, who noted that patients correctly diagnosed as having this condition maintained the ability to sustain circulation and respiration, control temperature, excrete wastes, heal wounds, fight infections, and, most dramatically, to gestate fetuses. The Uniform Determination Of Death Act in the United States adopted the more conservative definition of death as the irreversible cessation of electrical activity in the whole brain, a conclusion reached by the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research in 1980.
The Fear Of Being Buried
There are many anecdotal references to people being declared dead by physicians and then coming back to life, sometimes days later in their coffin or when embalming procedures are about to begin. From the mid-18th century onwards, there was an upsurge in the public's fear of being mistakenly buried alive and much debate about the uncertainty of the signs of death. Various suggestions were made to test for signs of life before burial, ranging from pouring vinegar and pepper into the corpse's mouth to applying red hot pokers to the feet or into the rectum. Writing in 1895, the physician J.C. Ouseley claimed that as many as 2,700 people were buried prematurely each year in England and Wales, although some estimates peg the figure to be closer to 800. In cases of electric shock, cardiopulmonary resuscitation for an hour or longer can allow stunned nerves to recover, allowing an apparently dead person to survive. People found unconscious under icy water may survive if their faces are kept continuously cold until they arrive at an emergency room, a phenomenon known as the mammalian diving response, in which metabolic activity and oxygen requirements are minimal, something humans share with cetaceans.
Around 1930, most people in Western countries died in their own homes, surrounded by family, and comforted by clergy, neighbors, and doctors making house calls. By the mid-20th century, half of all Americans died in a hospital, and by the start of the 21st century, only about 20 to 25% of people in developed countries died outside of a medical institution. The shift from dying at home towards dying in a professional medical environment has been termed the Invisible Death, a gradual transition that occurred over the years until most deaths now occur outside the home. This shift has profound implications for how society handles the dead, as the physical remains of a person, commonly known as a corpse or body, are usually interred whole or cremated, though among the world's cultures, there are a variety of other methods of mortuary disposal. In Tibet, for instance, the body is given a sky burial and left on a mountain top, while mummification or embalming is also prevalent in some cultures to retard the rate of decay. The rise of secularism resulted in material mementos of death declining, and in Brazil, death is counted officially when it is registered by existing family members at a cartório, a government-authorized registry, where the indirect costs and burden of filing for a death lead to more appealing, unofficial, local, and cultural burials.
The Cost Of Living
The leading cause of human death in developing countries is infectious disease, while the leading causes in developed countries are atherosclerosis, cancer, and other diseases related to obesity and aging. By an extremely wide margin, the largest unifying cause of death in the developed world is biological aging, leading to various complications known as aging-associated diseases. Of the roughly 150,000 people who die each day across the globe, about two thirds die of age-related causes, and in industrialized nations, the proportion is much higher, approaching 90%. In developing nations, inferior sanitary conditions and lack of access to modern medical technology make death from infectious diseases more common than in developed countries, with tuberculosis killing 1.8 million people in 2015 and malaria causing about 2.7 million deaths annually. Tobacco smoking killed 100 million people worldwide in the 20th century and could kill 1 billion people worldwide in the 21st century, according to a World Health Organization report. Suicide overtook car crashes as the leading cause of human injury deaths in the U.S. in 2012, followed by poisoning, falls, and murder, while accidents and disasters, from nuclear disasters to structural collapses, also claim lives, with the 1975 Banqiao Dam Failure being one of the deadliest incidents of all time, with varying estimates of up to 240,000 dead.
The Science Of Senescence
Senescence refers to a scenario when a living being can survive all calamities but eventually dies due to causes relating to old age, and conversely, premature death can refer to a death that occurs before old age arrives, for example, human death before a person reaches the age of 75. Animal and plant cells normally reproduce and function during the whole period of natural existence, but the aging process derives from the deterioration of cellular activity and the ruination of regular functioning. The aptitude of cells for gradual deterioration and mortality means that cells are naturally sentenced to stable and long-term loss of living capacities, even despite continuing metabolic reactions and viability. In the United Kingdom, for example, nine out of ten of all the deaths that occur daily relates to senescence, while around the world, it accounts for two-thirds of 150,000 deaths that take place daily. Almost all animals who survive external hazards to their biological functioning eventually die from biological aging, known in life sciences as senescence, but some organisms experience negligible senescence, even exhibiting biological immortality, such as the jellyfish Turritopsis dohrnii, the hydra, and the planarian.
The Afterlife And The Mind
Much interest and debate surround the question of what happens to one's consciousness as one's body dies, with the belief in the permanent loss of consciousness after death often called eternal oblivion, while the belief that the stream of consciousness is preserved after physical death is described by the term afterlife. Near-death experiences describe the subjective experiences associated with impending death, and some survivors of such experiences report it as seeing the afterlife while they were dying, seeing a being of light and talking with it, life flashing before the eyes, and the confirmation of cultural beliefs of the afterlife. In Buddhist doctrine, death functions as a reminder of the value of having been born as a human being, and rebirth as a human being is considered the only state in which one can attain enlightenment, while in Christianity, after death, the individual will undergo a separation from mortality to immortality, their soul leaving the body, entering a realm of spirits, and following this separation of body and spirit, resurrection will occur. In Hindu texts, death is described as the individual eternal spiritual jiva-atma exiting the current temporary material body, and the soul exits this body when the body can no longer sustain the conscious self, which may be due to mental or physical reasons or, more accurately, the inability to act on one's kama, and during conception, the soul enters a compatible new body based on the remaining merits and demerits of one's karma and the state of one's mind at the time of death.
The Psychology Of Grief
Death studies is a field within psychology, and to varying degrees people inherently fear death, both the process and the eventuality, as it is hard wired and part of the survival instinct of all animals. Discussing, thinking about, or planning for their deaths causes them discomfort, and this fear may cause them to put off financial planning, preparing a will and testament, or requesting help from a hospice organization. Mortality salience is the awareness that death is inevitable, and self-esteem and culture are ways to reduce the anxiety this effect can cause, while the awareness of someone's own death can cause a deepened bond in their in-group as a defense mechanism. Different people have different responses to the idea of their deaths, and philosopher Galen Strawson writes that the death that many people wish for is an instant, painless, unexperienced annihilation, where the person dies without realizing it and without being able to fear it. Animals have sometimes shown grief for their partners or friends, and when two chimpanzees form a bond together, sexual or not, and one of them dies, the surviving chimpanzee will show signs of grief, ripping out their hair in anger and starting to cry, and if the body is removed, they will resist, they will eventually go quiet when the body is gone, but upon seeing the body again, the chimp will return to a violent state.