The argument upon which Malthus relied was already prepared for him. The dreams of the revolutionary enthusiasts supposed either a neglect of the actual conditions of human life or a belief that those conditions could be radically altered by the proposed political changes. The cooler reasoner was entitled to remind them that they were living upon solid earth, not in dreamland. The difficulty of realising Utopia may be presented in various ways. Malthus took a point which had been noticed by Godwin. In the conclusion of his _Political Justice_,[204] while taking a final glance at the coming millennium, Godwin refers to a difficulty suggested by Robert Wallace. Wallace had[205] said that all the evils under which mankind suffers might be removed by a community of property, were it not that such a state of things would lead to an 'excessive population.' Godwin makes light of the difficulty. He thinks that there is some 'principle in human society by means of which everything tends to find its own level and proceed in the most auspicious way, when least interfered with by the mode of regulation.' Anyhow, there is plenty of room on the earth, at present. Population may increase for 'myriads of centuries.' Mind, as Franklin has said, may become 'omnipotent over matter';[206] life may be indefinitely prolonged; our remote descendants who have filled the earth 'will probably cease to propagate';[207] they will not have the trouble of making a fresh start at every generation; and in those days there will be 'no war, no crimes, no administration of justice'; and moreover, 'no disease, anguish, melancholy, or resentment.' Briefly, we shall be like the angels, only without the needless addition of a supreme ruler. Similar ideas were expressed in Condorcet's famous _Tableau historique des progrès de l'esprit humain_,[208] written while he was in daily fear of death by the guillotine, and so giving the most striking instance on record of the invincibility of an idealist conviction under the hardest pressure of facts.
The argument of Malthus is a product of the whole previous course of speculation. The question of population had occupied the French economists. The profound social evils of France gave the starting-point of their speculations; and one of the gravest symptoms had been the decay of population under the last years of Louis XIV. Their great aim was to meet this evil by encouraging agriculture. It could not escape the notice of the simplest observer that if you would have more mouths you must provide more food, unless, as some pious people assumed, that task might be left to Providence. Quesnay had laid it down as one of his axioms that the statesman should aim at providing sustenance before aiming simply at stimulating population. It follows, according to Gulliver's famous maxim, that the man who makes two blades of grass grow where one grew before deserves better of his country than the 'whole race of politicians put together.' Other writers, in developing this thesis, had dwelt upon the elasticity of population. The elder Mirabeau, for example, published his _Ami des hommes ou traité de la population_ in 1756. He observes that, given the means of subsistence, men will multiply like rats in a barn.[209] The great axiom, he says,[210] is 'la mesure de la subsistance est celle de la population.' Cultivate your fields, and you will raise men. Mirabeau replies to Hume's essay upon the 'Populousness of ancient nations' (1752), of which Wallace's first treatise was a criticism. The problem discussed by Hume and Wallace had been comparatively academical; but by Malthus's time the question had taken a more practical shape. The sentimentalists denounced luxury as leading to a decay of the population. Their prevailing doctrine is embodied in Goldsmith's famous passage in the _Deserted Village_ (1770):