 One can distinguish the domain of economics from the domain of other social scientific inquiries either by specifying some set of causal factors or by specifying some range of phenomena. The phenomena with which economists are concerned are production, consumption, distribution and exchange—particularly via markets. But since so many different causal factors are relevant to these, including the laws of thermodynamics, metallurgy, geography and social norms, even the laws governing digestion, economics cannot be distinguished from other inquiries only by the phenomena it studies. Some reference to a set of central causal factors is needed. Thus, for example,  John Stuart Mill  maintained that, “Political economy…[is concerned with] such of the phenomena of the social state as take place in consequence of the pursuit of wealth. It makes entire abstraction of every other human passion or motive, except those which may be regarded as perpetually antagonising principles to the desire of wealth, namely aversion to labour, and desire of the present enjoyment of costly indulgences.” (1843, Book VI, Chapter 9, Section 3) In Mill’s view, economics is mainly concerned with the consequences of individual pursuit of tangible wealth, though it takes some account of less significant motives such as aversion to labor.