public good or private benefit. Robert D. Putnam (1993) suggested that social capital would facilitate co-operation and mutually supportive relations in communities and nations and would therefore be a valuable means of combating many of the social disorders inherent in modern societies, for example crime. In contrast, others focus on the private benefits derived from the web of social relationships in which individual actors find themselves. This is reflected in Nan Lin's concept of social capital as "Investment in social relations with expected returns in the marketplace." This may subsume the concepts of some others such as Bourdieu, Flap and Eriksson. Newton (1997) treats social capital as a subjective phenomenon formed by values and attitudes that influence interactions. Nahapiet and Ghoshal (1998), in their examination of the role of social capital in the creation of intellectual capital, suggest that social capital should be considered in terms of three clusters: structural, relational, and cognitive. Definitional issues A number of scholars have raised concerns about the imprecision in defining social capital. Portes (2000), for example, notes that the term has become so widely used, including in mainstream media, that "the point is approaching at which social capital comes to be applied to so many events and in so many different contexts as to lose any distinct meaning." The term capital is used by analogy with other forms of economic capital, as social capital is argued to have similar (although less measurable) benefits. However, the analogy may be misleading in that, unlike financial forms of capital, social capital is not depleted by use; instead, it is depleted by non-use (use it or lose it). In this respect, it is similar to the economic concept of human capital. Robison, Schmid, and Siles (2002) review various definitions of social capital and conclude that many do not satisfy the formal requirements of a definition. They assert that definitions must be of the form A=B, while many explanations of social capital describe what it can be used to achieve, where it resides, how it can be created, or what it can transform. In addition, they argue that many proposed definitions of social capital fail to satisfy the requirements of capital. They propose that social capital be defined as sympathy: the object of another's sympathy has social capital; those who have sympathy for others provide social capital. This proposition appears to follow Adam Smith, Theory of Moral Sentiments