Enhancement not only allows the possibilities of a healthy fullness and exuberance, but of a rather ominous extravagance, aberration, monstrosity ... This danger is built into the very nature of growth and life. Growth can become over-growth, life 'hyper-life' ... The paradox of an illness which can present as wellness - as a wonderful feeling of health and well-being, and only later reveal its malignant potentials - is one of the chimaeras, tricks and ironies of nature.
Oliver Sacks