Knill is a co-founder of the field of Expressive Arts Therapy. The discipline was developed in the United States during the 1970s as a practice and art based therapy. It is rooted in phenomenology, the deliberations of systems theory, and ideas of humanist psychology. The philosophy of the Expressive Arts program at Lesley, which Knill helped to found, “embraced an intermodal or interdisciplinary approach to the arts therapies” integrating “indigenous healing systems” along with “contemporary philosophical developments such as phenomenology, hermeneutics and deconstructionism”. Knill introduced the method of "intermodal decentering" in the 1990s. This method is based upon systems theory. It leads the patient out of the constriction of thinking and acting tied to their problem and into a space of playful and artistic shape/form. This leeway allows for sensual experiences that are neither predictable nor intentional. The client can find "solution possibilities" in the concretely observable "here" and "now" of the artistic process. In this context, Knill developed a "theory of crystallization". According to him, this theory is based fundamentally upon the phenomenological premise that in artistic therapy, meaning arises exclusively from out of aesthetic material, through which therapist and client step to one another in relation. In 1990 Knill introduced the concept of the ‘incommunicable third’ into scientific discourse in order to indicate that moment in which something new emerges abruptly or unforeseen from out of a therapeutic encounter. Knill developed an artistic methodology for work with large communities following the methodology of Expressive Arts Therapy. He calls this methodology “community art”.
Institutions
In addition to developing the theoretical foundations of Expressive Arts Therapy, Knill has contributed to the foundation of several institutions dedicated to the field. Knill helped to found the Expressive Arts Therapy program at Lesley University in the 1970s. He founded the International School for Interdisciplinary Studies in Switzerland in 1984. The institution has training centers in Canada, Denmark, Germany and the United States. The Canadian branch has since been remained the CREATE Institute. In 1994, Knill founded the European Graduate School in Saas-Fee, Switzerland
Titles in German
Ausdruckstherapie. Künstlerischer Ausdruck in Therapie und Erziehung als intermediale Methode. Halle: Ohlsen Verlag, 1979..
Medien in Therapie und Ausbildung. Bremen: Eres Verlag, 1983..
Kunstorientiertes Handeln in der Begleitung von Veränderungsprozessen. Zurich: EGIS Verlag, 2005..
Lösungskunst. Lehrbuch der kunst- und ressourcenorientierten Arbeit. Göttingen: Vandenhoeck & Ruprecht, 2010..