Thomas Malthus, in his Essays on Population, put forth the theory that while human populations multiply at a geometric rate, food supply increase only at an arithmetic rate. Therefore, he argued, there will be a point at which population must grow beyond the supply of food available.

This theory became known as the Malthusian doctrine, and Charles Darwin found in this doctrine the inspiration for his theory of natural selection. He felt that it is through competition for the limited resources that the fit (people) were selected for survival and the unfit were rejected. For a long time, this logic was accepted without any question.

However, more recently, biology has demonstrated that there is natural control of numbers in animal population. So far, no animal population has ever increased beyond the limits of food supply. No direct competition between individuals for available food has yet been witnessed. The number is regulated by physiological and behavioural laws in the absence of climatic disasters.

The present attempts at population control all over the world are a conscious effort, while wars, famines and accidents continue to reduce the human population in less conscious ways.