Some philosophical views share a deterministic teleological idea of technical progress linked to the myth of the completeness of technics, that is to say, to the idea that the ultimate objective of technical progress is the complete technification of reality. Here, a theory of the progress of technics is proposed according to which its character is cumulative, not teleological, contingent, not deterministic, and radically incomplete. One notable consequence of this model is that it emphasizes our moral responsibility for the development of technics.