Several authors have mentioned R. Murray Schafer's use of extramusical ideas as a distinguishing characteristic of his music. The thesis examines his use of extramusical ideas throughout his career as a composer.

The concepts of "extramusical" and "extramusical references" are explained with reference to Leonard Meyer's book 'Emotion and Meaning in Music', and it is stated that the extramusical ideas in Schafer's works are examined through the extramusical references found in his scores. These include: texts, program notes, descriptive titles, dramatic effects, score directions and visual references. The historical debate concerning the relative merits of including or not including extramusical references in music (absolute vs. non-absolute music) is briefly discussed, and Schafer's views are quoted... 

https://era.library.ualberta.ca/items/bd502f74-97c7-462c-b3ff-333d37511eb2