The English term Complex Seeing is taken from Bertolt Brecht's writing on theatre and opera. First found in Brecht's notes to the "Threepenny Opera", a subsequently edited and updated version was published. This text can be found in English translation as "The Literarization of Theatre" from 1931, in Brecht on Theatre, where the key passage on complex seeing reads:

Can we draw the following conclusion?
Brecht meant to describe the comple seeing
It's impossible to say