The theory of Malthus is based on three errors, namely (a) that the
population increases in geometrical progression, a progression of 1, 2,
4, 8, 16, and so on upwards; (b) that the food supply increases in
arithmetical progression, a progression of 1, 2, 3, 4, 5, and so on
upwards; and (c) that overpopulation is the cause of poverty and disease.
If we show that _de facto_ there _is_ no overpopulation it obviously cannot
be a cause of anything, nor be itself caused by the joint operation of the
first two causes. However, each of the errors can be severally refuted.
(a) In the first place, it is true that a population _might_ increase in
geometrical progression, and that a woman _might_ bear thirty children
in her lifetime; but it is wrong to assume that because a thing _might_
happen, it therefore does happen. The population, as a matter of fact, does
not increase in geometrical progression, because Nature [5] places her own
checks on the birth-rate, and no woman bears all the children she might
theoretically bear, apart altogether from artificial birth control.
(b) Secondly, the food supply does not of necessity increase in
arithmetical progression, because food is produced by human hands, and is
therefore increased in proportion to the increase of workers, unless the
food supply of a country or of the world has reached its limit. The food
supply of the world _might_ reach a limit beyond which it could not
be increased; but as yet this event has not happened, and there is no
indication whatsoever that it is likely to happen.
Human life is immediately sustained by food, clothing, shelter, and fuel.
Food and clothing are principally derived from fish, fowl, sheep,
cattle, and grain, all of which _tend_, more so than man, to increase in
_geometrical_ ratio, although actually their increase in this progression
is checked by man or by Nature. As regards shelter there can be no increase
at all, either arithmetical or geometrical, apart from the work of human
hands. Again, the stock of fuel in or on the earth cannot increase of
itself, and is gradually becoming exhausted. On the other hand, within
living memory, new sources of fuel, such as petroleum, have been made
available, and old varieties of fuel have been used to better advantage,
as witness the internal-combustion engine driven by smoke from sawdust.
Moreover, in the ocean tides is a vast energy that one day may take the
place of fuel.
(c) Thirdly, before anyone can reasonably maintain that overpopulation
is the cause of poverty and disease, it is necessary to prove that
overpopulation actually exists or is likely to occur in the future. By
overpopulation we mean the condition of a country in which there are so
many inhabitants that the production of necessaries of livelihood is
insufficient for the support of all, with the result that many people are
overworked or ill-fed. Under these circumstances the population can be said
to _press on the soil_: and unless their methods of production could be
improved, or resources secured from outside, the only possible remedy
against the principle of diminishing returns would be a reduction of
population; otherwise, the death-rate from want and starvation would
gradually rise until it equalled the birth-rate in order to maintain an
unhappy equilibrium.