Abstract: The paper proposes a rethinking of the concept of nature in terms of non-predetermined possibility. In the first part the author retraces the notion of nature implied by the theory of mediation structures; in the second part he moves to a critical rereading of Aristotle and Hegel and their respective understanding of nature in order to outline a basis for a redefinition of nature that could help the contemporary critical theory, social and human sciences. Put succinctly, nature is conceived as a constitutive exteriority that functions as an internal element. Nature is limiting its own self in such a way that it produces the very distinction between natural and not natural as a natural distinction. Thus it allows us to question the nature of technology, of history, of society, of culture, in short, of everything that traditionally has been opposed to nature.