This chapter describes Prodi's peculiar strategy to explain life phenomena. This is a model based on the concept of relation or biological meaning that always privileges the relation over the terms of the relation. For Prodi a relation is never a one-way affair, but, on the contrary, it is always a to and fro. This is because the general epistemic model for life phenomena is that of the circle, a figure that has no preferred direction. This method allows Prodi to avoid any kind of determinism, be it genetic or cultural.