Science has always issued medical promissory notes. In the 17th century, Francis Bacon promised that an understanding of the true mechanisms of disease would enable us to extend life almost indefinitely; René Descartes thought that 1,000 years sounded reasonable. But no science has been more optimistic, more based on promises, than medical genetics.
Recently, I read an article promising that medical genetics will soon deliver ‘a world in which doctors come to their patients and tell them what diseases they are about to have’. Treatments can begin ‘before the patient feels even the first symptoms!’ So promises ‘precision medicine’, which aims to make medicine predictive and personalised through detailed knowledge of the patient’s genome.