And “at all times and places, that is dear ... which it costs much labour to acquire.”[18] And again: “The value of any commodity to the person who possesses it [and wishes to exchange it] is equal to the quantity of labour which it enables him to purchase or command. Labour, therefore, is the real measure of the exchangeable value of all commodities.”[19] The first of these, in accordance with which it is asserted that value is governed (in the philosophical primitive conditions) by cost in labor, may be called the _labor-cost standard_. The second finds a convenient name as the _labor-command standard_.[20] The two play separate and important parts in the subsequent history of the labor theory of value. Ricardo adopted the labor-cost standard as applicable to the conditions of advanced or capitalistic society and repudiated the labor-command measure. Malthus, on the contrary, defended the latter and rejected the former.[21] 4. Since the amount of the value of a good is asserted to bear certain definite relations to the amount of labor it costs or commands, it is a very proper question to inquire how quantity of labor is measured in any particular case. Adam Smith remarks that the quantity of money for which a good can be exchanged is “a plain palpable object,” but that the quantity of labor which it commands, indirectly through the use of money is “an abstract notion, which, though it can be made sufficiently intelligible, it (_sic_) is not altogether so natural and obvious.”[22] He suggests, in that most excellent and familiar Smithian sentence, that the proportions in which different concrete kinds of labor exchange (or count for quantity of labor in general or in the abstract) are “adjusted not by any accurate measure, but by the higgling and bargaining of the market, according to that sort of rough equality which, though not exact, is sufficient for carrying on the business of common life.”[23] Nevertheless there are certain principles which enable us to define quantity of labor in a general way. Time alone spent at a task does not determine the quantity of labor put forth. The different degrees of hardship endured and of ingenuity exercised in different employments must also be considered.