书城公版James Mill
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第46章 Malthus(4)

Cobbett's language was rougher than Southey's;but the poet-laureate and the author of 'two-penny trash'were equally vehement in sentiment.Malthus,on the other hand,was accepted by the political economists,both Whig and Utilitarian.Horner and Mackintosh,lights of the Whigs,were his warm friends as well as his disciples.He became intimate with Ricardo,and he was one of the original members of the Political Economy Club.He took abuse imperturbably;was never vexed 'after the first fortnight'by the most unfair attack;and went on developing his theories,lecturing his students,and improving later editions of his treatise.Malthus died on 23rd December 1834.

II.THE RATIOS

The doctrine marks a critical point in political economy.Malthus's opponents,as Mr.Bonar remarks,15attacked him alternately for propounding a truism and for maintaining a paradox.A 'truism'is not useless so long as its truth is not admitted.

It would be the greatest of achievements to enunciate a law self-evident as soon as formulated,and yet previously ignored or denied.Was this the case of Malthus?Or did he really startle the world by clothing a commonplace in paradox,and then explain away the paradox till nothing but the commonplace was left?

Malthus laid down in his first edition a proposition which continued to be worried by all his assailants.

Population,he said,when unchecked,increases in the geometrical ratio;the means of subsistence increase only in an arithmetical ratio.Geometrical ratios were just then in fashion.16Price had appealed to their wonderful ways in his arguments about the sinking fund;and,had pointed out that a penny put out to 5per cent compound interest at the birth of Christ would,in the days of Pitt,have been worth some millions of globes of solid gold,each as big as the earth.Both Price and Malthus lay down a proposition which can easily be verified by the multiplication-table.

If,as Malthus said,population doubles in twenty-five years,the number in two centuries would be to the present number as 256to 1,and in three as 4096to 1.If,meanwhile,the quantity of subsistence increased in 'arithmetical progression,'the multipliers for it would be only 9and 13.It follows that,in the year 2003,two hundred and fifty-six persons will have to live upon what now supports nine.So far,the case is clear.But how does the argument apply to facts?For obvious reasons,Price's penny could not become even one solid planet of gold.Malthus's population is also clearly impossible.That is just his case.The population of British North America was actually,when he wrote,multiplying at the assigned rate.What he pointed out was that such a rate must somehow be stopped;and his question was,how precisely will it be stopped?The first proposition,he says 17(that is,that population increased geometrically),'I considered as proved the moment that the American increase was related;and the second as soon as enunciated.'To say that a population increases geometrically,in fact,is simply to say that it increases at a fixed rate.The arithmetical increase corresponds to a statement which Malthus,at any rate,might regard as undeniable;namely,that in a country already fully occupied,the possibility of increasing produce is restricted within much narrower limits.In a 'new country,'as in the American colonies,the increase of food might proceed as rapidly as the increase of population.Improved methods of cultivation,or the virtual addition of vast tracts of fertile territory by improved means of communication,may of course add indefinitely to the resources of a population.But Malthus was contemplating a state of things in which the actual conditions limited the people to an extraction of greater supplies from a strictly limited area.Whether Malthus assumed too easily that this represented the normal case may be questionable.At any rate,it was not only possible but actual in the England of the time.His problem was very much to the purpose.His aim was to trace the way in which the population of a limited region is prevented from increasing geometrically.If the descendants of Englishmen increase at a certain rate in America,why do they not increase equally in England?That,it must be admitted,is a fair scientific problem.Finding that two races of similar origin,and presumably like qualities,increase at different rates,we have to investigate the causes of the difference.