This paper aims at contrasting two different approaches of the relations between innovation and competition. The traditional one focuses on the existence of an optimal structure and the other focuses on viability requirements. It shows that viability conditions cannot be reduced to the enforcement of a specific market structure. Co-ordination conditions allow both the dismantlement of existing market structures and the stabilisation of new ones. The latter cannot be defined a priori, but only in relation with the process of change itself. It will be different according to the way co-ordination takes place. As a consequence, rather than enforcing a presumed optimal structure competition policy should consist in comparing different organisational arrangements with respect to viability requirements.
