Selection made on the basis of consequences is a causal mode found only in "living" things. Selection happens at the level of species, individual and culture. Human behaviour is the joint product of the contingencies of existence responsible for natural selection and of contingencies by which the behaviour of individuals are selected, including the contingencies maintained by an evolved social environment. Behaviour is not caused by immaterial processes inside the organism. It is the contingencies for behaviour and the behaviour itself that have to be analysed, and possibly changed. The implications for treatment may be great.