A kind is an interactive human kind when the existence and nature of that kind of people depends on our classificatory practices—when there is an interaction between the kind and how we think and talk about people. Ian Hacking argues that people suffering from Multiple Personality Disorder (Dissociative Identity Disorder) form such a kind, since their existence as a kind depends on how doctors use that category and on patients’ awareness of it. This looks like a special case of the social construction of a kind of person. Hacking calls his view `nominalism’ indicating that the kinds are not real. Khalidi suggests that this verdict may spread to other apparently real or natural kinds. Thus interactive kinds look to be a threat to realism about kinds. I examine these arguments. Are interactive kinds real or not? Are any kinds real? I conclude that we can regard such interactive kinds as real kinds.”

Alexander Bird is Bertrand Russell Professor of Philosophy and fellow of St.John’s College, Cambridge. Prior to his appointment last year he was Peter Sowerby Professor of Philosophy and Medicine at KCL and, before that, Professor of Philosophy at the University of Bristol. Professor Bird was chair of the philosophy sub-panel for the Research Excellence Framework, 2014.

Professor Bird works in the philosophy of science, the philosophy and history of medicine, metaphysics and epistemology. Within the philosophy of medicine he has a particular interest in the methodological issues in causal and statistical inference. His new book, ‘Knowing Science’, is soon to be published by Oxford University Press.