Medicine urgently needs a broader approach to diagnosis: one that reveals more of the true causes of disease. As we slowly unravel the complexities and potency of psychoneuroimmunology, we understand more of the extent to which the biology common to all human beings is modulated by the biography unique to each one. And yet the evidence on which clinical medicine is based remains rooted in the generalisations derived from randomised controlled trials, from which every trace of individual difference has been deliberately excluded.

The problem is that human beings are not simply passive consumers of disease and injury. The first person to point out the fundamental significance of the meanings that animals, including humans, attach to their environment and experience was the Estonian zoologist Jakob von Uexküll (1864-1944). He argued that each individual was the result firstly of modification undergone by the species during evolution but secondly, and at least as importantly, of adaptation occurring within the individual …