There are multiple criticisms of the use of the term in both its original context, as an attempt to define and explain the living, and its various expanded usages, such as applying it to self-organizing systems in general or social systems in particular. Critics have argued that the concept and its theory fail to define or explain living systems and that, because of the extreme language of self-referentiality it uses without any external reference, it is really an attempt to give substantiation to Maturana's radical constructivist or solipsistic epistemology, or what Danilo Zolo has called instead a "desolate theology". An example is the assertion by Maturana and Varela that "We do not see what we do not see and what we do not see does not exist". The autopoietic model, said Rod Swenson, is "miraculously decoupled from the physical world by its progenitors ... (and thus) grounded on a solipsistic foundation that flies in the face of both common sense and scientific knowledge".