The absence of a distinct appreciation of such difficulties gives to his speculation that one-sided character which alienated his more sentimental contemporaries.It was natural enough in a man who was constantly confronted by the terrible development of pauperism in England，and was too much tempted to assume that the tendency to reckless propagation was not only a very grave evil，but the ultimate source of every evil.The doctrine taken up in this unqualified fashion by some of his disciples，and preached by them with the utmost fervour as the one secret of prosperity，shocked both the conservative and orthodox whose prejudices were trampled upon，and such Radicals as inherited Godwin's or Condorcet's theory of perfectibility.Harsh and one-sided as it might be，however，we may still hold that it was of value，not only in regard to the most pressing difficulty of the day，but also as calling attention to a vitally important condition of social welfare.The question，however，recurs whether，when the doctrine is so qualified as to be admissible，it does not also become a mere truism.
An answer to this question should begin by recognising one specific resemblance between his speculations and Darwin's.Facts，which appear from an older point of view to be proofs of a miraculous interposition，become with Malthus，as with Darwin，the normal results of admitted conditions.Godwin had admitted that there was some 'principle which kept population on a level with subsistence.''The sole question is，'says Malthus，59'what is this principle？
Is it some obscure and occult cause？a mysterious interference of heaven，'inflicting barrenness at certain periods？or 'a cause open to our researches and within our view？'Other writers had had recourse to the miraculous.
One of Malthus's early authorities was Süssmilch，who had published his G?ttliche Ordnung in 1761，to show how Providence had taken care that the trees should not grow into the sky，the antediluvians had been made long-lived in order that they might have large families and people an empty earth，while life was divinely shortened as the world filled up.
Süssmilch，however，regarded population as still in need of stimulus.
Kings might help Providence.A new Trajan would deserve to be called the father of his people，if he increased the marriage-rate.Malthus replies that the statistics which the worthy man himself produced showed conclusively that the marriages depended upon the deaths.The births fill up the vacancies，and the prince who increased the population before vacancies arose would simply increase the rate of mortality.60If you want to increase your birth-rate without absolutely producing famine，as he remarks afterwards，61make your towns unhealthy，and encourage settlement by marshes.You might thus double the mortality，and we might all marry prematurely without being absolutely starved.His own aim is not to secure the greatest number of births，but to be sure that the greatest number of those born may be supported.62The ingenious M.Muret，again，had found a Swiss parish in which the mean life was the highest and the fecundity smallest known.He piously conjectures that it may be a law of God that 'the force of life in each country should be in the inverse ratio of its fecundity.'He needs not betake himself to a miracle，says Malthus.63The case is simply that in a small and healthy village，where people had become aware of the importance of the 'preventive check，'the young people put off marriage till there was room for them，and consequently both lowered the birthrate and raised the average duration of life.
Nothing，says Malthus very forcibly，has caused more errors than the confusion between 'relative and positive，and between cause and effect.'64He is here answering the argument that because the poor who had cows were the most industrious，the way to make them industrious was to give them cows.Malthus thinks it more probable that industry got the cow than that the cow produced industry.