Malthus interpreted overpopulation as an evil that would reduce the amount of food available per person.
Malthus' theory was based on the assumption that the power of population is much greater than the power of the earth to provide subsistence for man. In his own words 'passion between the sexes is an inevitable phenomenon' hence, when unchecked, population would grow at such a high rate that it would outstrip food supply. According to Malthus, disease, food shortage and death due to starvation, were nature's way to control population. He proposed that human beings adopt measures like infanticide, abortion, delay in marriage and strict following of celibacy to check population growth.
According to him, human society could never be perfected. He believed that man is a lazy animal, who would lead a satisfied life and procreate as long as his family was well fed. However, as soon as human population would feel constraints in food supply due to increase in population, he would again work hard to provide enough for his family. This might lead to an increase in agricultural production to provide for all, but at the same time man would be back to his complacent stage, where all his needs would be fulfilled. This would start the cycle of overpopulation and food shortage, all over again.
Some critics of Malthus, like Karl Marx, argued that Malthus failed to recognize the potential of human population to increase food supply. Malthus is accused by many to have failed to comprehend man's ability to use science and technology to increase food supply to meet the needs of an increasing population.Thinkers from the field of social sciences have criticized Malthus for his belief that the human society could never be made perfect. Malthus opposed all political, social and economic reforms that did not aim at controlling birth rate. His own methods of checking population growth was criticized as being impractical. From his writings some have interpreted Malthus as a rigid and pessimistic individual. However, he is also viewed by some as a pragmatic thinker, who put a check on the unbridled enthusiasm of some who viewed increase in population as a means of progress.