Concepts that gain their identity partly through their contrast with one another: seems/is, light/dark, physical/mental, individual/social, masculine/feminine, yin/yang, are possible examples. Philosophical problems arise if it is asked whether one of the pair is fundamental: which is the doughnut, and which is merely the hole defined by the doughnut. For instance, ethical implications arise when people write as if masculinity is central, and femininity ‘The Other’.