The quote from Marilynne Robinson's "Gilead" suggests that trying too hard to justify one's beliefs can lead to doubt and instability. When individuals engage in deep discussions about fundamental truths or ultimate concerns, they often encounter limitations in their reasoning. This struggle to articulate the essence of their beliefs may highlight the very uncertainties underlying them.

The act of defending beliefs can inadvertently expose their vulnerabilities, making individuals question their faith or trust in those beliefs. This highlights the paradox that, although striving to defend what one holds dear is a natural impulse, it can also create unsettling feelings and a sense of inadequacy regarding the arguments presented. Ultimately, some truths may remain beyond the reach of logical explanation.