It would be quite illogical, and inconsistent with physiological facts, to aver that, were the poor less given to indulge the pleasures of sense, their fecundity would be modified in an appreciable degree. CHAPTER VI. ETHICS OF PREVENTION. _Fertility the law of life.--Man interprets and controls this law.--Marriage law necessary to fix paternal responsibility.--Malthus's high ideal.--If prudence the motive, continence and celibacy violate no law.--Post-nuptial intermittent restraint.--Ethics of prevention judged by consequences.--When procreation is a good and when an evil.--Oligantrophy.--Artificial checks are physiological sins._ "So God created man in his own image, in the image of God created He him, male and female created He them, and God blessed them and God said unto them, 'Be fruitful and multiply, and replenish the earth.'"--(Genesis i., 27-28). This commandment was repeated to Noah and his sons. Whether Moses was recording the voice of God, or interpreting a physiological law is immaterial to this aspect of a great social question. The fact remains that in obedience to a great law of life, all living things are fruitful and multiply and replenish the earth, and multiplication in a state of nature is limited only by space and food. In a state of nature, reproduction is automatic, and only in this state is this physiological law, or this divine command obeyed. The reason of man intervenes, and interprets, and modifies this law. A community of men becomes a social organism, calls itself a State, and limits the law of reproduction. It decrees that the sexes shall, if they pair, isolate themselves in pairs, and live in pairs whether inclined to so live or not. If the State has a right so to interpret and limit the law of reproduction, a principle in human affairs is established, and its decree that individuals shall not mate before a certain age, or not mate at all, is only a further application of the same principle. By the law of reproduction a strong instinct, second only in force and universality to the law of self-preservation, is planted in the sexes, and upon a blind obedience to this force, the continuity of the race depends. The tendency in the races of history has been to over-population, or to a population beyond the food supply, and there is probably no race known to history that did not at some one period of its rise or fall suffer from over-population. States have mostly been concerned, therefore, with restraining or inhibiting the natural reproductive instinct of their subjects through marriage laws which protect the State, by fixing paternal responsibility. There were strong reasons why a State should not be over-populated, and only one reason why it should not be under-populated. That one reason was the danger of annihilation from invasion.