Health as intra-systemic integrity: rethinking the foundations of systems biology and nanomedicine.

In current research on systems biology and nanomedicine, we often find an ideal of a new science-based preventive medicine. I consider how disease, cause, explanation, diagnosis, and treatment are understood within this ideal, with special attention to the role of nanoscience and technology in elucidating the "circuit diagram" of a healthy system. I argue that the developmental systems theory that informed George Engel's biopsychosocial model addresses some deficiencies in the current systems ideal, but it needs to be integrated with an ethical analysis that is more attentive to the socioeconomic, cultural, and institutional factors that condition how we understand and manage disease. We also need a richer account of top-down causal paths if we are to appropriately understand diseases as disruptions of inter- and intra-systemic integrity.