This paper is a short critical essay about the value of 'battery tests', to predict the longevity of groups and individuals. It takes a standpoint that there is a long history behind efforts to define the concepts of 'physiological age', and 'chronological age', and their relationships with 'lifespan'. The conclusion is that clinical measurements have little value in defining biological age and lifespan. These latter are the outcomes of uncorrected molecular errors which are far removed in time and place from their clinical expressions.