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OF THE MENTAL AND PHYSICAL PREMISES OF POLI
TICAL ECONOMY, AND OF THE LOGICAL CHARACTER OF THE DOCTRINES THENCE DEDUCED.
In my last lecture I stated that, according to the best English authorities, Political Economy is defined as “the science which states the laws regulating the production and distribution of wealth, so far as they depend on the action of the human mind." I also observed that, while agreeing substantially in the views, as regards the nature and limits of the science, of those who propounded this definition, yet the language of the definition did not appear to me correctly to represent those views. I therefore ventured to propose a change of phraseology, and offered two definitions, either of which appeared to me to fulfil the necessary requirements. These definitions were as follows, viz., “the science, which, accepting as ultimate facts the principles of human nature, and the physical laws of external nature, investigates the laws of the production and distribution of wealth which result from their combined operation;" or this—“the science which traces the phenomena of the production and
distribution of wealth up to their causes, in the principles of human nature and the laws and events of the external world.” The points in which the received definition and either of those which I proposed agree, were then stated and illustrated at some length. It remains now that I should advert to the points in which they differ, and state the grounds on which the proposed change is to be vindicated.
According to the received definition, then, Political Economy is represented as being conversant with the laws of the production and distribution of wealth, so far forth only as these laws “ depend on the action of the human mind ; ” and, its business being thus restricted to the tracing of the operation of mental laws, to the exclusion of physical, it is represented as a purely mental or moral science. I have altered this part of the definition, because I conceive that the province of Political Economy is not so narrow as this language represents it; no economists, not even the authors of the definition in question, having ever yet been content to confine their investigations within the limits here prescribed. It appears to me, on the contrary, that the laws and phenomena of wealth, which it belongs to Political Economy to explain, depend equally on physical as on mental laws, that Political Economy stands in precisely the same relation to physical as to mental nature, and that, if it is to be ranked in either of these departments of speculation, it is as well entitled to be placed in the one as in the other.
The expressions “physical,” and “mental,” as applied to science, have hitherto been employed to designate those branches of knowledge of which physical and mental phenomena respectively form the subject-matter. Thus, Chemistry is considered as a physical science because the subject-matter on which chemical inquiry is exercised, viz., external nature, is physical. Psychology, on the other hand, is a mental science ; the subject-matter of it being mental states and feelings. And as the office of the chemist consists in observing and analyzing material objects with a view to discovering the laws of their elementary constitution ; so, that of the psychologist consists in endeavouring, by means of reflection on what passes in his own mind, to ascertain the laws by which the phenomena of our mental constitution succeed and produce each other. If this be a correct statement of the principle on which the designations “mental” and “physical” are applied to the sciences, it seems to follow that Political Economy does not find a place under either category. Neither mental nor physical nature forms
the subject-matter of the investigations of the political | economist. He does not consider the laws according to which physical phenomena take place, nor yet those according to which mental phenomena take place. The subject-matter of his science is wealth, which is neither a purely physical nor a purely mental object, but possesses a complex character, 'equally derived from both departments of nature, and the laws of which are neither mental nor physical laws, though they are dependent, and as I maintain, dependent equally on the laws of matter and on those of mind.
Let us consider, for example, the causes which determine the rate of wages. This, it will be admitted on all hands, is an economic problem. It is evident that the objects which the labourer receives are material objects, but those material objects are invested by the mind with a peculiar attribute in consequence of which they are considered as possessing value ; and it is in their complex character, as physical objects invested with the attribute of value, that the political economist considers them. The subject matter, therefore of the wages-problem possesses qualities derived alike from physical and from mental nature ; consequently, if it is to be denominated from the nature of its subject-matter, it is equally entitled or disentitled to the character of a physical or mental problem.
But it is said that Political Economy considers the problem no further than as it depends on the action of the human mind. The food and clothing which the labourer consumes have, no doubt, physical properties, as the labourer himself has a physical as well as a mental nature ; but with the physical properties, we are told, the political economist has no concern : he considers those objects so far forth only as they possess value, and value is a purely mental conception. But is this true ? Does the political economist -does Mr. Senior, e. g., in his purely scientific treatment of this question-entirely put out of consideration the physical properties of the commodities which
the labourer consumes, or the physiological conditions on which the increase of the labouring population depends ? What is the solution of the wages-problem ? Wages, it will be said, depend on demand and supply; or, more explicitly, on the relation between the amount of capital applied to the payment of wages, and the number of labourers seeking employment. But the amount of capital employed in the payment of wages depends, amongst other causes, on the productiveness of industry in raising the commodities of the labourer's consumption—a circumstance which is equally dependent on the laws of physical nature as on the mental qualities which the workman brings to his task. The number of labourers seeking employment, again, depends, amongst other causes, on the laws of population ; while these are determined as much by the physiological laws of the body, as the psychological laws of the mind; the political economist taking equal cognizance of both.
It thus appears that, as the subject-matter of Political Economy, viz., wealth, possesses qualities derived equally from the world of matter as from that of mind, so its premises are equally drawn from both these departments of nature. The latter point, indeed, is admitted by those economists who nevertheless, by what appears to me to be a strange oversight, represent the science as investigating the laws of wealth no further than as they depend on the laws of the human mind.
But perhaps this point will be made more clear