Some thoughts on "A Portrait of the Artist as a Young Man" by James Joyce. This post assumes knowledge of the book's plot.
Each of the first 4 chapters ends with an "epiphany" or "breakthrough" which Stephen experiences.
In chapters 1 and 3 this breakthrough is in the direction of the church. In chapter 1 he goes to the school principal and questions his punishment. Through this action, intellectually he makes sense of life in the religious school, and socially he gains respect and standing in it. In chapter 3 he abandons his dissolute lifestyle and becomes religious.
In chapters 2 and 4 this breakthrough is in the direction of women. In chapter 2 he gains the courage to visit a prostitute. In chapter 4 he meets the girl bathing on the beach.
The key figure in chapter 5 is Cranly. He is religious and so represents the church. At the same time he has "womanly" eyes and, at least in the sense of having sensitive relationships with other people, represents women. Thus he personifies what Stephen has been chasing throughout the previous 4 chapters. For most of chapter 5 Stephen is accompanied by Cranly. Yet by the end Stephen has made a final break with him.
I do not think chapter 5 is an abandonment of the previous chapters. Rather, it is a development from them, like chapter 3 is a development from 1 and 4 from 2. Stephen hopes to find two things in life: truth and beauty. The first he searched for in the church, the second in women. In chapter 5, rather than forgetting these objectives, he chooses a different source for them. In the past he has drawn on external sources, the church and women, in order to bring truth and beauty into his life. From now on, their source will be internal. As an "artist", through his works he will create truth and beauty.
That is what he tries to do in his complex theoretical discourses and in his poem. Whether or not these creations of his are intellectually and artistically successful is beside the point; he is only a young artist and will have many later opportunities to improve. At the very least, their complexity indicates that he is trying hard. :)