A third criterion of personal identity is that we are our bodies, that is to say, that personal identity is constituted by some brute physical relation between, for example, different bodies or different life-sustaining systems at different times. Although this view is still somewhat unpopular, developments about personal identity theory in the 1990s promise an ideological change, as versions of the so-called somatic criterion, associated with Eric Olson and Paul Snowdon, attract a continuously growing number of adherents.