Theories of population growth: Malthus Theory

An Essay on the Principle of Population as it Affects the Future Improvement of Society (1798)

Malthus’ two premises

• Population growth, if left unchecked, increases in a geometric progression over time: 1, 2, 4, 8, 16, 32, 64, etc.

• The capacity to grow the food supply needed to feed a growing population increases in an arithmetic progression over time: 1, 2, 3, 4, 5, 6, 7, etc.

Malthus’ Basic Idea

• Population growth outpaces the ability to increase the food supply.

Malthus’ 1 Principles of Population

Population is necessarily limited by the means of subsistence (food).

Malthus’ 2 Principles of Population

Population invariably increases when the means of subsistence increases.

Malthus’ 3 Principles of Population

But…population will always increase faster than the food supply unless prevented by certain checks.

Malthus’ 3 checks on population growth

1) “Moral restraint”

2) “Vice” (Contraception, abortion, infanticide)

3) “Misery” (Starvation, war, disease)

2 Problems of Malthus

1) Rapid increase in the food supply

2) Birth rates started to decline