Final Answer:
The converse principle of "Sex doesn't have to look like sex," which forms the foundation of chapter 17, is the idea that seemingly non-sexual elements or actions can carry significant sexual or erotic undertones.
Step-by-step explanation:
In chapter 16, when Foster asserts, "Sex doesn't have to look like sex," he introduces the concept that sexual themes or nuances can be subtly embedded in various forms, not strictly limited to explicit depictions of sexual acts.
The foundation of chapter 17 builds upon the converse principle, exploring the ways in which non-sexual elements, symbols, or actions can convey or evoke sexual meanings. This principle aligns with the broader theme of literary analysis that emphasizes the layers of meaning and symbolism present in literature.
Chapter 17 likely delves into the exploration of how authors use implicit or symbolic elements to convey sexual themes, deepening the reader's understanding of the nuanced ways in which sexuality is represented in literature. The converse principle serves as a gateway to unraveling the intricate layers of meaning within the context of sexual representation in literature.