Death by simple definition is just 'the end of life'. All human beings are destined to die one day as per their 'predetermined time' from the moment of their birth. There are a number of factors that influence the longevity and the period of life that an individual will have at their disposal.
The causes of death range from the deterioration from the old age, illness, accidents, homicides, to perhaps extreme psychological distress. Death occurs when respiration and heart cease to function but it is said that spirit remains in a body for at least a short while. It is sometimes called 'twin sister of sleep' as during sleep there is a temporary black-out but heart continues to functions whereas in death the systems of body cease to function. Every individual's clock has been set by nature or a divine entity and when the time is right, the individual cease to exist.
To date, it has not been determined by scientists as what triggers death irrespective of its causes. Estimation of life expectancy at birth is determined globally based on a number of factors. There are some computer programmes that can also calculate the approximate time of death. This calculation method is sometimes called "Death Meter". A number of questions are asked revolving around the current life style with specific inquiry related to country of residence, tobacco exposure, alcohol consumption, unprotected sex and intravenous drug usage. The other questions relate to dental hygiene, exposure to sun, physical exercise, any medical illness like hypertension, cardiac ailment, cancer, diabetes, liver disease etc. Dietary habits like frequency of eating processed food, consumption of poultry, meat or fish and the way it was cooked, percentage of fruits and vegetable consumption, taking multivitamin supplements, exposure to air pollution, family history of chronic diseases, amount of stress in life and longevity of parents and grandparents. This calculation would exclude the possibility of accidental deaths.
There are a number of views about the concept of death among different religious groups, some believe in one life on earth and eternal life after death, there is also a belief about reincarnation and multiple lives on earth. For Hindus, when lessons of this life have been learned, the soul leaves the physical body, which then returns its elements to the earth. The awareness, will, memory and intelligence which we think of ourselves continue to exist in the soul body.
There are a number of rituals that are performed after death of an individual by relatives in almost all cultures and religions with the possible concept of relieving the dead body spiritually from this world. The most intriguing aspect is the triggering factor that would initiate death and the predetermined timing as if a clock running out of battery. There are a number of hypotheses: is the death time programmed in genetics? Is there a 'Trigger Factor' in the form of a chemical that is released in the body affecting the cardiac rhythmicity? Is there a factor responsible for body deterioration culminating in cessation of function that remains unidentified until death time? Can timing of death be altered by maintenance of body by virtue of early identification of pathologies, appropriate nutrition and exercise?
Does psyche play an important role in preventing death or prolonging life? A number of people get the intuition about their impending death. Is there any brain centre or area that harbours this 'death time' memory that warn some people about the possible time of their death? Does the near-death experiences with autoscopy in particular give any insight in this regard?
Scientists are struggling to find the triggering factor that initiate death. If this factor is found, can death be prevented? Like a number of unanswered queries and mysteries, this issue remains to be unfolded albeit in a scientific manner.
(The writer is a Professor of Psychiatry at Memorial University of Newfoundland, Canada.)