In this chapter, we will see that recognizing and responding to the myriad of living beings that surround us is not necessarily defending ourselves by eliminating them, but rather negotiating a compromise with them. The obligatory interactions of the organism with living beings often occur without leading to pathology, without even manifesting in a perceptible way. This reciprocal accommodation implies an immunity of a new type, dynamic, relational, never acquired, and leads to a different look at pathogens and disease.