Good health is a matter of having the right molecules in the right place at the right time. This may seem self-evident, but the idea that health is determined mainly by molecules has only gained acceptance in recent years.

Consider this in historical perspective. A century ago health was regarded as a function of body parts – if you had a regular bowel and a strong heart you were OK. This anatomic model of health was superseded in due course by models based on organ function, the so-called system-based (physiologic) approach. But physiologic systems are interdependent: you can't have an effective gastrointestinal system without a nervous system, or a competent immune system without a hemopoietic system, or a responsive cardiovascular system without an endocrine system. This limitation has so far prevented even the most integrated biomedical curricula from communicating a wholly holistic view of human biology.

A popular response to such difficulties has been the proposal that students of the twenty-first century should no longer be force-fed so much information. Facts have become unfashionable, an irrelevance to the higher goal of imbuing trainees with creative insights and self-learning potential. What is needed, many believe, is a way of transmitting broad scientific principles without the burden of detail.