The development of infrastructural facilities in the form of transport and communications systems, energy, water supply, health and education is a necessary precondition for investment in directly productive activities such as agriculture and manufacturing. The importance of social and economic overhead capital was emphasised by Adam Smith, who argued that it was the duty of the state to erect and maintain those public institutions and those public works which, though they may be in the highest degree advantageous to a great society, are, however, of such a nature, that the profit could never repay the expense to any individual or small number of individuals, and which it therefore cannot be expected that any individual or small number of individuals should erect or maintain (Smith, 1976 and 1950, p. 244).