Abstract
This chapter explores in detail the specific relationship between human beings and the biological and extra-biological causes of infectious disease. The fact that a bacterium and a human being seem to share a common evolutionary heritage is not irrelevant to our experience with bacteria, but rather a hint as to the nature of a story that has gone on for billions of years, that we are still experiencing (and interpreting through the lens of concepts like “medicine” and “disease”). From an evolutionary perspective, disease agents and humans share certain foundational characteristics which developed towards the dawn of life, and it is these characteristics that inform on the relationship between diseases and humans today.