becoming an actual, science. Torrens observes that all sciences have to pass through a period of controversy; but thinks that economists are emerging from this stage, and rapidly approaching unanimity. In twenty years, says this hopeful prophet, there will scarcely exist a 'doubt of its' (Political Economy's) 'fundamental principles.'[356] Torrens thinks that Ricardo has generalised too much, and Malthus too little; but proposes, with proper professions of modesty, to take the true _via media_, and weld the sound principles into a harmonious whole by a due combination of observation and theory. The science, he thinks, is 'analogous to the mixed mathematics.'[357] As from the laws of motion we can deduce the theory of dynamics, so from certain simple axioms about human nature we can deduce the science of Political Economy. M'Culloch, at starting, insists in edifying terms upon the necessity of a careful and comprehensive induction, and of the study of industrial phenomena in different times and places, and under varying institutions.[358] This, however, does not prevent him from adopting the same methods of reasoning. 'Induction' soon does its office, and supplies a few simple principles, from which we may make a leap to our conclusions by a rapid, deductive process. The problems appear to be too simple to require long preliminary investigations of fact. Torrens speaks of proving by 'strictly demonstrative evidence' or of 'proceeding to demonstrate' by strict analysis.[359] This is generally the preface to one of those characteristic arithmetical illustrations to which Ricardo's practice gave a sanction. We are always starting an imaginary capitalist with so many quarters of corn and suits of clothes, which he can transmute into any kind of product, and taking for granted that he represents a typical case. This gives a certain mathematical air to the reasoning, and too often hides from the reasoner that he may be begging the question in more ways than one by the arrangement of his imaginary case. One of the offenders in this kind was Nassau Senior (1790-1864), a man of remarkable good sense, and fully aware of the necessity of caution in applying his theories to facts. He was the first professor of Political Economy at Oxford (1825-1830), and his treatise[360] lays down the general assumption of his orthodox contemporaries clearly and briefly. The science, he tells us, is deducible from four elementary propositions: the first of which asserts that every 'man desires to obtain additional wealth with as little sacrifice as possible'; while the others state the first principles embodied in Malthus's theory of population, and in the laws corresponding to the increasing facility of manufacturing and the decreasing facility of agricultural industry.[361] As these propositions include no reference to the particular institutions or historical development of the social structure, they virtually imply that a science might be constructed