t what caused death must diminish population. Malthus shows the
necessity of observing other collateral results. The gap may be made
so great as to diminish population; but it may be compensated by a
more rapid reproduction; or, the rapidity of reproduction may itself
be the cause of the disease; so that to remove one kind of mortality
may be on some occasion to introduce others. The stream is dammed on
one breach to flow more strongly through other outlets.[267]

This is, I conceive, to say simply that Malthus was introducing a
really scientific method. The facts taken in the true order became at
once intelligible instead of suggesting mysterious and irregular
interferences. Earlier writers had been content to single out one
particular set of phenomena without attending to its place in the more
general and complex processes, of which they formed an integral part.
Infanticide, as Hume had pointed out, might tend to increase
population.[268] In prospect, it might encourage people to have
babies; and when babies came, natural affection might prevent the
actual carrying out of the intention. To judge of the actual effect,
we have to consider the whole of the concrete case. It may be carried
out, as apparently in the South Sea Islands, so generally as to limit
population; or it may be, as in China, an indication that the pressure
is so great that a number of infants become superfluous. Its
suppression might, in the one case, lead to an increase of the
population; in the other, to the increase of other forms of mortality.
Malthus's investigations illustrate the necessity of referring every
particular process to its place in the whole system, of noting how any
given change might set up a set of actions and reactions in virtue of
the general elasticity of population, and thus of constantly referring
at every step to the general conditions of human life. He succeeded in
making many points clear, and of showing how hastily many inferences
had been drawn. He explained, for example, why the revolutionary wars
had not diminished the population of France, in spite of the great
number of deaths,[269] and thus gave an example of a sound method of
inquiry which has exercised a great influence upon later observers.
Malthus was constantly misunderstood and misrepresented, and his
opponents often allege as fatal objections to his doctrine the very
facts by which it was really supported. But we may, I think, say, that
since his writing no