Mr. Malthus devotes the first and second chapters of his fourth book to an inquiry into our obligations to regulate the sexual passion by considerations of prudence, &c. into the general capacity of human nature to act from rational motives, and the good effects which would result from such a conduct. He begins his third chapter in the following manner.
‘He who publishes a moral code, or system of duties, however firmly he may be convinced of the strong obligation on each individual strictly to conform to it, has never the folly to imagine that it will be universally or even generally practised. But this is no valid objection against the publication of the code. If it were, the same objection would always have applied; we should be totally without general rules; and to the vices of mankind arising from temptation, would be added a much longer list, than we have at present, of vices from ignorance.’ [This is well said, and ’tis a kind of good deed to say well.] ‘Judging merely from the light of nature, if we feel convinced of the misery arising from a redundant population, on the one hand, and of the evils and unhappiness, particularly to the female sex, arising from promiscuous intercourse, on the other, I do not see how it is possible for any person, who acknowledges the principle of utility as the great foundation of morals, to escape the conclusion that moral restraint, till we are in a condition to support a family, is the strict line of duty; and when revelation is taken into the question, this duty undoubtedly receives very powerful confirmation. At the same time, I believe that few of my readers can be less sanguine in their expectations of any great change in the general conduct of men on this subject than I am; and the chief reason, why, in the last chapter, I allowed myself to suppose the universal prevalence of this virtue, was, that I might endeavour to remove any imputation on the goodness of the Deity, by shewing that the evils arising from the principle of population were exactly of the same nature as the generality of other evils which excite fewer complaints, that they were increased by human ignorance and indolence, and diminished by human knowledge and virtue; and on the supposition, that each individual strictly fulfilled his duty, would be almost totally removed; and this, without any general diminution of those sources of pleasure, arising from the regulated indulgence of the passions, which have been justly considered as the principal ingredients of human happiness.’