The subject of this symposium is sometimes introduced by asking whether machines could think. This way of introducing it may be misleading, for it may seem as if it were merely about a particular activity, called ‘thinking’. The question would then seem to have the same character as ‘Can machines make a noise?’. But thinking is not something that can be treated in isolation from other personal qualities. What we need to consider is whether, or to what extent, a machine could participate in the whole complex of qualities, activities, attitudes, thoughts, feelings and moral relationships that we regard as essential to being a person—whether, in this sense, machines could be persons.