Interesting parallels can be drawn between Freud's The Pleasure Principle and Peter Schaffer's play, Equus. For the sake of brevity, in this blog I will focus on the role that Alan Strang's "chanting" serves in the play and how this chanting can be related directly to the pleasure principle. To begin with, Alan's chanting is an obvious rewriting of Christian geneology, where horses have taken the place of biblical figures. This rewriting is also evident in Alan's replacement of Christian artwork in his bedroom with that of a horse. In the play, the source of Alan's relationship with religion is through his mother, and his morphing of religion into a form of "horse worship" can be related to his early childhood experience with a horse (which is sexually charged) and his father, Frank Strang, who brought that experience to a traumatic end.
Here, Alan's conflation of religion/horses/ sexuality/and the maternal can be read in terms of Freud's Oedipal complex. Alan is attempting to possess his mother and displace his father. The religious core of Alan and his mother's relationship (which excludes the father) shifts to Alan's worship of horses as a way to frustrate Frank's attempt to remove religion from the household, thus breaking the tie between Alan and his wife. Frank Strang consistently upsets Alan, even stopping Alan's chanting by "coughing" outside of his bedroom door.
The repetitive nature of Alan's chanting can be read in Freudian terms of Alan taking an active rather than a passive role in his relationship with his father. However, Alan's sense of agency through the worship of horses and his Oedipal desire to possess his mother is illusory, since he still believes that his father is always "watching." Frank is an authoritarian figure who, to Alan, seems "all seeing" and "all knowing."