Mechanists also challenge the idea that disciplines are related by way of the relationship between their theories. Darden and Maull (1977) argued that disciplinary fields often integrate their findings through the construction of interfield theories, appealing to diverse material relationships between items in the different fields’ domains: relations such as cause and effect, part and whole, or structure and function. Darden and Maull did not offer a general account of interfield theories, but Bechtel presciently suggested that such theories often take the form of descriptions of mechanisms (Bechtel 1988: 101–102).