It is especially important that we consider the philosophical implications of Maturana's work. All theoretical work in the natural and social sciences has philosophical implications in that, explicitly or implicitly, it embodies particular epistemological and ontological presuppositions. However, most work does not produce results which, in themselves, have philosophical implications. This is not the case with autopoiesis and the allied theories of cognition since they constitute, inter alia, a theory of the observer. That is, they claim to define the possibilities and limitations, biologically, of cognition and therefore of observation, description, and knowledge. This, of course, makes them highly self-referential, for the results must apply equally to the theory that generated them. This, in itself, does not cause a contradiction, but it does place a premium on consistency. Maturana himself is very well aware of all this, and has continually made explicit what he sees as the radical philosophical implications of autopoiesis.