Plato is also a forerunner of Adam Smith in his recognition of the fact that the division of labor depends for its advance upon a great increase in the size and complexity of the state.163 It means a multiplication of trades, a development of industry,164 the entrance of the retail trader (κάπηλος),165 and the invention of money as a means of exchange.166 The necessity of the division of labor between states is also recognized. It is impossible to establish a city where it will not be in need of imports (ἐπεισαγωγίμων). International trade therefore arises, and with it are born the merchant (ἔμπορος) and the sailor class, together with all those who are engaged in the labor of the carrying trade.167 Thus Plato, the idealist, and reputed enemy of trade and industry, develops them directly out of the basal principle of his Republic. He appreciates the necessity of a full-fledged industry and commerce to the existence even of a primitive state, and his hostility to them is actually directed only against what he terms their unnatural use.168 Moreover, in his opinion, one function of the division of labor should be to limit them to the performance of their proper tasks, and keep them from degenerating into mere money-making devices. It should also result in limiting such vocations to the less capable classes since the rulers should be artisans of freedom.169
It would take us too far afield to discuss the diverse ways in which Plato uses his principle. We may observe in passing, however, that he applies it to war, in his interesting criticism of the citizen-soldier;170 to the finer arts, even when they are quite similar to each other;171 to politics, as noted above; to justice and the moral life in general;172 and to the intellectual life, in his unsparing criticism of the superficial versatility and dilettantism of the contemporary Athenian democracy, which trusts the government to any incompetent, professes to be able to imitate everything, and makes the many-sided Sophist (πολλαπλοῦς) the man of the hour.173 Though he begins with the development of the principle as an economic fact, his primary interest in it is as a moral and intellectual maxim. The fact that the cobbler sticks to his last is only a symbol (εἴδωλον) of justice.174 Nevertheless Plato does appreciate to a remarkable degree the economic