Time
The abstract and concrete imagery of time is used to question some assumptions about systemic injustice. One can suppose a question that Walker is defeating: "Why does America's past of racism and slavery matter today, since those institutions have been removed?" Her treatment of time is therefore a relevant part of her discussion of race, because she is attempting to show that time doesn't work in a linear way, but in a karmic way. She shapes this abstract imagery with concrete details, most notably, the example of Martin Luther King, Jr. and the use of the atomic bomb in WWII.
Self and race
Walker mentions the imagery of one's own body as a key factor in the development of self. By encountering the outside world, one is treated based on their appearance, which shapes (through behavioral psychology) one's opinion of one's self. Therefore, if a community holds a low opinion of Black people, say, then as a Black child, Walker might enter her community with unwarranted negative feedback from others that shapes her abstract sense of self. Broadly, this is the imagery of self-worth, both concrete and abstract.
Influence and academy
By mentioning her specific influences, Walker constructs an abstract imagery for the way art and literature can help heal the adverse affects of systemic injustice. In simpler terms, she shows that through reading and writing, we can help heal each other. This brings her into intimate discussions about the way Zora Neale Hurston, Flannery O'Connor, and Martin Luther King helped augment and shape her sense of destiny and passion.
Paradise
By invoking the imagery of paradise (family in repose, or "Our Mothers' Gardens"), Walker invites the reader to consider the difference between real life and the ideal. Ideally, we would not have to address the problems that face us. Ideally, things might be perfect, but she invokes this imagery to illustrate her point that actually, there is much to improve in real life. The invocation of paradise imagery makes the issues of systemic injustice more obvious by contrast.
