Windelband is now mainly remembered for the terms "nomothetic" and "idiographic", which he introduced. Nomothetic explanations are probabilistic and usually incomplete. Gordon Allport (1937) described two major ways to study personality&colon; the nomothetic and the idiographic. Explanations in social theories can be idiographic or nomothetic. FAP is an idiographic (as opposed to nomothetic) approach to psychotherapy. The 19th-century views, on the other hand, are nomothetic; that is, they provide laws. Nomothetic refers to the use of generalization rather than specific properties in the same context.