Chapter XXVII: Section 2: Mr. Pell's Generalisations Criticised

Mr. Pell defines the law of births and deaths in two generalisations. The first is: "We have seen that it is a necessary condition of the success of the evolutionary scheme that the variation of the inherited potential degree of fertility between species and species must bear an inverse proportion to their capacity for survival." [53] At first glance this statement appears hard to be understood; but it is obviously true--because it means that a species that is well adapted to its environment can survive with a low degree of fertility, whereas a species that is not well adapted to its environment requires a high degree of fertility in order to survive. Mr. Pell considers that a "capacity for survival" is synonymous with "nervous energy"; but, as our total knowledge of nervous energy is limited to the fact that it is neither matter nor any known force, the change in words does not mark a real advance in knowledge.

The second generalisation is that "the variation of the degree of animal fertility in response to the direct action of the environment shall bear an inverse proportion to the variation of the survival capacity under that environment." [54] Here Mr. Pell and I part company. I have already (Chapter III) disputed the causal connection between birth-rate and death-rate which Mr. Pell here asserts. His generalisation is made by assuming that birth-rates and death-rates rise and fall together: that conditions which produce a high death-rate will also produce a high birth-rate and that conditions which cause a low death-rate will also cause a low birth-rate; that the increase or decline of a population is due to the direct action of the environment; and finally that "the _actual_ degree of fertility is decided by the direct action of the environment." [55] On that last rock Mr. Pell's barque sinks. The mistake here is analogous to the old Darwinian fallacy, abandoned by Huxley and by Romanes, that natural selection is a creative cause of new species. Even if the hypothesis of evolution--and it is merely a hypothesis--be accepted, the only view warranted by reason is that variation of species and their actual degree of fertility may be produced, not by the direct action of environment, but by the _reaction_ of species to their environment--a very different story.

There is no statistical evidence to prove a uniform correspondence between birth-rates and death-rates, and it is improbable that there should be a physical law of nature whose operations cannot be demonstrated by mathematical proof. Moreover, we know that the same conditions which cause a high birth-rate may cause a low death-rate. In the case of the first settlers in a new country the death-rate is low because the diseases of civilisation are absent and the settlers are usually young, whereas the birth-rate is high. If fifty young married couples settle on the virgin soil of a new country it is probable that for many years an enormous birth-rate, of over 100, will coexist with a low death-rate.

In reality a high birth-rate may coexist with a low death-rate, or with a high death-rate. For example, there is a difference between natural and artificial poverty, the first being brought about by God, or, if any reader prefers to have it so, by Nature, and the second being made by man. Under conditions of natural poverty small groups of people in an open country are surrounded by land not yet cultivated: whereas artificial poverty means a population overcrowded and underfed, living in dark tenements or in back-to-back houses, breathing foul air in ill-ventilated rooms seldom lit by the sun, working long hours in gas-lit workshops for a sweated wage, buying the cheapest food in the dearest market, and drugged by bad liquor. In either case their existence is threatened, although for very different reasons, and the birth-rate rises; but under conditions of natural poverty the death-rate is low, whereas in slums the death-rate is high.