 A therapy client's presenting symptoms are understood as an activation and enactment of specific constructs.The principle of symptom coherence can be found in varying degrees, explicitly or implicitly, in the writings of a number of historical psychotherapy theorists, including Sigmund Freud (1923), Harry Stack Sullivan (1948), Carl Jung (1964), R. D. Laing (1967), Gregory Bateson (1972), Virginia Satir (1972), Paul Watzlawick (1974), Eugene Gendlin (1982), Vittorio Guidano & Giovanni Liotti (1983), Les Greenberg (1993), Bessel van der Kolk (1994), Robert Kegan & Lisa Lahey (2001), Sue Johnson (2004), and others.The principle of symptom coherence maintains that an individual's seemingly irrational, out-of-control symptoms are actually sensible, cogent, orderly expressions of the person's existing constructions of self and world, rather than a disorder or pathology.