Various scholars have attempted to explain the relationships that exist between population and factors such as resources, economy, politics, and other social issues.
Modern population theory is generally thought to have evolved in the late-eighteenth century, in the writings of Malthus.
Considering views about the relationship between population growth and socio-economic, political, and environmental factors, theories of the population developed by different scholars can be grouped into two broad categories: Malthusian/Neo-Malthusian and Anti-Malthusian.
Malthusian and neo-Malthusian theories are pessimistic, and the anti-Malthusian theories are optimistic.
Malthusian Population Theory
Malthus reflected: The population in each country is growing fast in comparison to the growth of available food-grains, and, there is, therefore, a fierce competition among them over the limited resources.
He believed that the supply of food can only increase by a constant amount, in arithmetical progression (1 – 2 – 3 – 4 – 5), but that the human population has a tendency to
multiply in geometric progression, (1 – 2 – 4 – 8 – 16), multiplying itself by a constant amount each time.
Therefore, eventually population would outstrip food supply until a catastrophe (positive checks) occurred.
This would be in the form of famine, diseases or war. Such
catastrophes would occur as human beings fought over increasingly scarce resources.
According to Malthus, in order to avoid the inevitable occurrence of the positive checks, human beings should adopt preventive checks (moral restraints, includes; late marriage, avoiding sexual conduct before marriage and having fewer children)
Anti-Malthusian Population Theories These are optimists who argue against Malthus. The two known theorists are Karl Marx and Ester Boserup.
Marxian Population Theory
Marx postulated his theory favoring the socialist ideology over capitalist.
There could be no population problem under a socialist mode of production and of ownership of resources.
When existing food supplies are inadequate to support some of the population, capitalism calls the unsupported people a surplus population.
Food scarcities are purely the result of unequal distribution of resources by capitalism.
Capitalist production is not targeted to meet the needs of poor people. Instead, its aim is to increase the accumulation of capital for the wealthy.
Marx’s solution to the problem of overpopulation was socialism with a new economic structure of society within a new social order.
Boserupian Population Theory
Boserup argues that population growth is independent of food supply and that population increase is a cause of changes in agriculture.
Boserup maintains that population growth is the cause rather than the result of agricultural change and that the principal change is the intensification of land use.
The theory of agricultural development posed by Boserup is subtler and complex than that of any of her predecessors.
She sees population pressure as a major cause of change in land use, agricultural technology, land tenure systems, and settlement form.
Boserup thought that “As the size of population increases, it results in technological innovations and advancement.”
For her, the population is an independent variable/factor, and agriculture is a dependent variable/factor.
She believed that population growth could not be controlled by the scarcity of food supply. Rather, the increasing demand for food caused by population growth would increase agricultural productivity by stimulating innovation in agricultural systems and technologies.
In this regard, she said that “Necessity is the mother of invention”