I have long been interested in classifications of people, in how they affect the people classified, and how the affects on the people in turn change the classifications. We think of many kinds of people as objects of scientific inquiry. Sometimes to control them, as prostitutes, sometimes to help them, as potential suicides. Sometimes to organise and help, but at the same time keep ourselves safe, as the poor or the homeless. Sometimes to change them for their own good and the good of the public, as the obese. Sometimes just to admire, to understand, to encourage and perhaps even to emulate, as (sometimes) geniuses. We think of these kinds of people as definite classes defined by definite properties. As we get to know more about these properties, we will be able to control, help, change, or emulate them better. But it's not quite like that. They are moving targets because our investigations interact with them, and change them. And since they are changed, they are not quite the same kind of people as before. The target has moved. I call this the 'looping effect'. Sometimes, our sciences create kinds of people that in a certain sense did not exist before. I call this 'making up people'. What sciences? The ones I shall call the human sciences, which, thus understood, include many social sciences, psychology, psychiatry and, speaking loosely, a good deal of clinical medicine. I am only pointing, for not only is my definition vague, but specific sciences should never be defined except for administrative and educational purposes. Living sciences are always crossing borders and borrowing from each other. The engines used in these sciences are engines of discovery but also engines for making up people. Statistical analysis of classes of people is a fundamental engine. We constantly try to medicalise: doctors tried to medicalise suicide as early as the 1830s. The brains of suicides were dissected to find the hidden cause. More generally, we try to biologise, to recognise a biological foundation for the problems that beset a class of people. More recently, we have hoped to geneticise as much as possible. Thus obesity, once regarded as a problem of incontinence, or weakness of the will, becomes the province of medicine, then of biology, and at present we search for inherited genetic tendencies. A similar story can be told in the search for the criminal personality.