ACT is a therapy that is based philosophically in clinical behavior analysis. Functional contextualism is the world view that underlies ACT. Theoretically ACT is based on RFT, which offers an account of how language creates pain and useless methods of dealing with it, and which suggests alternative contextual approaches to these domains. ACT uses metaphors, experiential exercises, and logical paradox to get around the literal content of language and to produce more contact with the ongoing flow of experience in the moment. The primary ACT components are challenging the control agenda, cognitive defusion, willingness, self as context, values, and commitment. ACT is part of the CBT tradition, although it has notable differences from traditional CBT. The main purpose of ACT is to relieve human suffering through helping clients live a vital, valued life.