OK, here are the main points of Thomas Malthus's theory of population:
1) Population growth is exponential (geometrical progression) while food production grows at a slower arithmetic progression. Over the long run, this will lead to population outstripping food supply.
2) There are two types of checks that operate to balance population growth and resources:
- Positive checks: These increase mortality and lower population growth, including disease, famine, and war. These will lead to a population crash.
- Preventative checks: These lower fertility and population growth, including moral restraints on marriage, birth control, prostitution, and late marriage. These help balance population and resources in a smoother manner.
3) Population will continue to grow until it is balanced by positive or preventative checks. There is a limit to how much population growth the earth can sustainably support.
4) Most measures to improve conditions and increase food supply will only increase population, exacerbating the problem. Ultra-materialism is not the solution.
5) Therefore, population growth needs to be checked to balance with food supply. The standard of living cannot be improved without controlling population. Poverty is largely self-induced bypopulation growth.
That's a high-level summary of Malthus's theory of population. There are debates around how right or wrong his theory was:
• He was right that uncontrolled population growth could outstrip resources and cause living standards to decline. But preventative checks and social/technological progress have avoided catastrophic collapses.
• He underestimated the capacity for improvement in agricultural productivity, as well as the capacity to decrease fertility through increased prosperity and access to birth control.
• His theory was criticized as pessimistic, although it highlighted an important issue. It prompted attempts to improve standards of living and balance population with resources.
• There are still concerns about overpopulation, resource depletion, and environmental degradation, showing Malthus's warnings were prescient to some extent. But catastrophic collapses have been avoided so far thanks to various countermeasures.
So in summary, Malthus was partially right in highlighting an important issue, but his theory was an oversimplification and underestimated humanity's ability to achieve balance in other ways. The debates around population and resource constraints remain complex to this day.