ABSTRACT
This chapter reviews simplicity in structure and timescales, in the ability to form simplified models, and in the ultimate causes of diseases. One level of simplicity is found in the structure of physiological circuits. Basic circuit motifs are sometimes wired together to produce larger circuits. In addition to the structural simplicity of a small number of circuit motifs, there is a second level of simplicity. This is the ability to treat circuits with minimal mathematical models that capture the essence of their behavior. In addition to simplicity in structure and in models, there is a third level of simplicity – the ability to discover core drivers of diseases and explain them in terms of basic physiological laws. Some diseases have clear causes or etiology, such as the pathogens in infectious diseases or germline mutations in rare genetic diseases.
