The Factors of Modernity That Is Cited to Promote Life Expectancy

If the average life expectancy doubles as a result of medical progress and better living conditions, all things being equal, the population also doubles.

Thus, demographers explain population growth during the first phase of demographic transition. When the impact of progress is felt, the population begins to increase as the mortality rate declines rapidly. Then, in a second phase, the birth rate declines in turn as a result of “morrow changes”, so that the population tends to stabilize (see the critique of this model in the following comments).

The demographic transition model has been drawn from the history of industrialized countries. But there’s a hit!

In the United Kingdom, the population increased by 3.5 in a century (6 to 21 million between 1750 and 1850). In the United States, it multiplied by 15 in 130 years (1820-1950). If only the increase in life expectancy was involved, assuming that it was of the order of 35 years earlier, it would have to be increased to more than 120 years in England, and 500 years in the USA! Such longevity can only be found among the Patriarchs of the Old Testament…

It is clear, therefore, that longer lifespan is only one of several factors for population growth: it can explain a doubling of the population. In the USA, immigration has also doubled the population, resulting in a quadrupling between the two factors. We’re still far from the number 15 quoted above!

The question of the fertility rate therefore remained to be examined closely. This depends on essentially psychological factors, particularly the sexual system. Too often it is forgotten that in these times morals have changed profoundly. While in the Middle Ages there was great sexual freedom, non-coitus behaviour was gradually condemned as abominations by moralists and doctors, who saw it as the cause of many diseases. What were the consequences for risk relationships? What are the consequences of this, especially in developing countries that are gradually permeating our Western morality?

These questions have never been asked…