In 1798 Thomas Robert Malthus, an Anglican clergyman, published his "Essay on the Principle of Population," in which he asserted that the human race was not capable of making any marked progress in a communistic society because of the tendency of population to increase more rapidly than food supply. To illustrate his view, he made the assumption that a population which increased naturally without being cut down or restricted by vice or misery in any of their forms would double itself at least every twenty-five years. Such a population, while itself increasing in geometrical ratio, could at best increase its food supply only in arithmetical ratio. In other words, Malthus maintained that while the population would, if unrestrained by vice or misery, tend to increase in twenty-five year periods according to the first of the following series, the food supply would at most increase according to the second series.

First Series - Geometrical Progression: 1, 2, 4, 8, 16, 32, 64, 128, 256.

Second Series - Arithmetical Progression: 1, 2, 3, 4, 5, 6, 7, 8, 9.

Or, starting out with a food supply sufficient for a given population, at the end of a period of nine times twenty-five years or two hundred and twenty-five years the population, if unchecked, would be two hundred and fifty-six times as large as at the beginning, whereas the food supply would be at most only nine times as large. Manifestly, such a large population could not subsist on such a small food supply. Therefore, said Malthus, they must have been cut down either by misery or by vice. This line of reasoning led him to deny "the possible existence of a society, all the members of which should live in ease, happiness and comparative leisure."

In later editions of the Essay Malthus introduced another "check" in addition to misery and vice, namely, moral restraint. By moral restraint Malthus meant a deferring of marriage from prudential motives until such a time as the persons being married would be economically able to support the probable number of their offspring, and the observance of strictly moral conduct during this period of deferred marriage.