An Essay on the Principle of Population | Page 5

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. It would be contrary to all our knowledge
of the qualities of land. The very utmost that we can conceive, is, that
the increase in the second twenty-five years might equal the present
produce. Let us then take this for our rule, though certainly far beyond
the truth, and allow that, by great exertion, the whole produce of the
Island might be increased every twenty-five years, by a quantity of
subsistence equal to what it at present produces. The most enthusiastic
speculator cannot suppose a greater increase than this. In a few
centuries it would make every acre of land in the Island like a garden.
Yet this ratio of increase is evidently arithmetical.
It may be fairly said, therefore, that the means of subsistence increase
in an arithmetical ratio. Let us now bring the effects of these two ratios
together.

The population of the Island is computed to be about seven millions,
and we will suppose the present produce equal to the support of such a
number. In the first twenty-five years the population would be fourteen
millions, and the food being also doubled, the means of subsistence
would be equal to this increase. In the next twenty-five years the
population would be twenty-eight millions, and the means of
subsistence only equal to the support of twenty-one millions. In the
next period, the population would be fifty-six millions, and the means
of subsistence just sufficient for half that number. And at the
conclusion of the first century the population would be one hundred
and twelve millions and the means of subsistence only equal to the
support of thirty-five millions, which would leave a population of
seventy-seven millions totally unprovided for.
A great emigration necessarily implies unhappiness of some kind or
other in the country that is deserted. For few persons will leave their
families, connections, friends, and native land, to seek a settlement in
untried foreign climes, without some strong subsisting causes of
uneasiness where they are, or the hope of some great advantages in the
place to which they are going.
But to make the argument more general and less interrupted by the
partial views of emigration, let us take the whole earth, instead of one
spot, and suppose that the restraints to population were universally
removed. If the subsistence for man that the earth affords was to be
increased every twenty-five years by a quantity equal to what the whole
world at present produces, this would allow the power of production in
the earth to be absolutely unlimited, and its ratio of increase much
greater than we can conceive that any possible exertions of mankind
could make it.
Taking the population of the world at any number, a thousand millions,
for instance, the human species would increase in the ratio of--1, 2, 4, 8,
16, 32, 64, 128, 256, 512, etc. and subsistence as--1, 2, 3, 4, 5, 6, 7, 8, 9,
10, etc. In two centuries and a quarter, the population would be to the
means of subsistence as 512 to 10: in three centuries as 4096 to 13, and
in two thousand years the difference would be almost incalculable,

though the produce in that time would have increased to an immense
extent.
No limits whatever are placed to the productions of the earth; they may
increase for ever and be greater than any assignable quantity, yet still
the power of population being a power of a superior order, the increase
of the human species can only be kept commensurate to the increase of
the means of subsistence by the constant operation of the strong law of
necessity acting as a check upon the greater power.
The effects of this check remain now to be considered.
Among plants and animals the view of the subject is simple. They are
all impelled by a powerful instinct to the increase of their species, and
this instinct is interrupted by no reasoning or doubts about providing
for their offspring. Wherever therefore there is liberty, the power of
increase is exerted, and the superabundant effects are repressed