This theory explains how population growth will happen from Malthus's point of view. The population grows in a geometrical way, which means population increases in 2, 4, 7, 12, 32, and 48. But the food production (or supply) increases arithmetically, which means in 2, 3, 4, 5, and 6. As a result of the population increasing, the level of food production (or supply) does not increase; it makes people not have enough food even for survival. People will start to die because of a lack of food supply.

Assumption
1) Food is necessary for life.
2) Food production increases arithmetically, e.g., 2, 3, 4, 5, and 6.
3) Population increases geometrically, e.g., 2, 4, 7, 12, 32, and 48.
4) Passion between men and women is unchanged.
5) Population is limited by food—population increases in the same proportion as food also increases unless prevented by some checks.

Diagram

Explain
The (X) axis is taken by time, and the (Y) axis is taken by quantity. The straight upwards line shows the food supply (or production) increases, and the curved line represents the increases. Over the time period, food production (or supply) increases gradually, but the population increases very fast and immeasurably. At the “E” point, population and food supply will be equal. After the point “E,” population overtakes the food production; population is greater than food supply, which causes food scarcity for people. Those who are after the E” point are starting to die because of scarcity of food supply (or production). Let's see what checks of prevention or population control there are.

Positive checks: Natural causes of population control, like disease spreading, natural disasters, famine (hunger death), war, etc., are positive preventive checks.

preventive checks: Artificially control the population through policy, like suggesting the policy of postponing the marriage until a later age because it’s made to reduce the birth rate. Moral restraint means legalizing the policy under the law for those who mislead the policy to give birth to more children or quickly marry before the fixed age at law; those who are not obeyed under the law take action against them. These are the two checks to control the population.