The growth of population is greater (growth in geometric progression) than the growth of the products of the land (growth in arithmetic progression), problems existing in the future to guarantee the subsistence of human beings. This British clergyman and scholar of great importance in political economy and demography In his book Essay on the principle of population (1798), maintains the idea that population grows faster than resources. The population has the capacity to double every 25 years. Existing in the future limits of space and food.