An Essay on the Principle of Population

It came in six parts between 1798 and 1826 Malthus. If one were to read The Population Bomb, they would find similar logic, but without the ideological underpinnings Malthus used to align himself with the British ruling class.

Anyway, Malthus wrote, "Yet in all societies, even those that are most vicious, the tendency to a virtuous attachment is so strong that there is a constant effort towards an increase of population. This constant effort as constantly tends to subject the lower classes of the society to distress and to prevent any great permanent amelioration of their condition".
—Malthus T.R. 1798. An essay on the principle of population. Chapter II, p18 in Oxford World's Classics reprint.

Malthus caught the ecological logic behind population growth and the struggle for existence, but we might say that he was like a Social Darwinist before Charles Darwin existed. "The way in which these effects are produced seems to be this. We will suppose the means of subsistence in any country just equal to the easy support of its inhabitants. The constant effort towards population... increases the number of people before the means of subsistence are increased. The food therefore which before supported seven millions must now be divided among seven millions and a half or eight millions. The poor consequently must live much worse, and many of them be reduced to severe distress. The number of laborers also being above the proportion of the work in the market, the price of labor must tend toward a decrease, while the price of provisions would at the same time tend to rise. The laborer therefore must work harder to earn the same as he did before. (See Karl Marx below) During this season of distress, the discouragements to marriage, and the difficulty of rearing a family are so great that population is at a stand. In the mean time the cheapness of labor, the plenty of laborers, and the necessity of an increased industry amongst them, encourage cultivators to employ more lab our upon their land, to turn up fresh soil, and to manure and improve more completely what is already in tillage, till ultimately the means of subsistence become in the same proportion to the population as at the period from which we set out. The situation of the laborer being then again tolerably comfortable, the restraints to population are in some degree loosened, and the same retrograde and progressive movements with respect to happiness are repeated".
—Malthus T.R. 1798. An essay on the principle of population. Chapter II, p19 in Oxford World's Classics reprint.

Malthus saw what we believe leads to epidemics because biohazard cleanup has arrived so late on the human scene. Societies experienced epidemics, famines, or wars: as a result it did not take long for populations to outgrow their their resources:

"The power of population is so superior to the power of the earth to produce subsistence for man, that premature death must in some shape or other visit the human race. The vices of mankind are active and able ministers of depopulation. They are the precursors in the great army of destruction, and often finish the dreadful work themselves. But should they fail in this war of extermination, sickly seasons, epidemics, pestilence, and plague advance in terrific array, and sweep off their thousands and tens of thousands. Should success be still incomplete, gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world".
—Malthus T.R. 1798. An essay on the principle of population. Chapter VII, p61[25]