CHAPTER 2.
The different ratio in which population and food increase--The necessary effects of these different ratios of increase--Oscillation produced by them in the condition of the lower classes of society--Reasons why this oscillation has not been so much observed as might be expected--Three propositions on which the general argument of the Essay depends--The different states in which mankind have been known to exist proposed to be examined with reference to these three propositions.
I said that population, when unchecked, increased in a geometrical ratio, and subsistence for man in an arithmetical ratio.
Let us examine whether this position be just.

I think it will be allowed, that no state has hitherto existed (at least that we have any account of) where the manners were so pure and simple, and the means of subsistence so abundant, that no check whatever has existed to early marriages, among the lower classes, from a fear of not providing well for their families, or among the higher classes, from a fear of lowering their condition in life.

Consequently in no state that we have yet known has the power of population been left to exert itself with perfect freedom.
Whether the law of marriage be instituted or not, the dictate of nature and virtue seems to be an early attachment to one woman.

Supposing a liberty of changing in the case of an unfortunate choice, this liberty would not affect population till it arose to a height greatly vicious; and we are now supposing the existence of a society where vice is scarcely known.
In a state therefore of great equality and virtue, where pure and simple manners prevailed, and where the means of subsistence were so abundant that no part of the society could have any fears about providing amply for a family, the power of population being left to exert itself unchecked, the increase of the human species would evidently be much greater than any increase that has been hitherto known.
In the United States of America, where the means of subsistence have been more ample, the manners of the people more pure, and consequently the checks to early marriages fewer, than in any of the modern states of Europe, the population has been found to double itself in twenty-five years.
This ratio of increase, though short of the utmost power of population, yet as the result of actual experience, we will take as our rule, and say, that population, when unchecked, goes on doubling itself every twenty-five years or increases in a geometrical ratio.
Let us now take any spot of earth, this Island for instance, and see in what ratio the subsistence it affords can be supposed to increase.

We will begin with it under its present state of cultivation.
If I allow that by the best possible policy, by breaking up more land and by great encouragements to agriculture, the produce of this Island may be doubled in the first twenty-five years, I think it will be allowing as much as any person can well demand.
In the next twenty-five years, it is impossible to suppose that the produce could be quadrupled.