In "Sunshine on Scotland Street," author Alexander McCall Smith explores themes of perception and reality, contrasting the fluidity of time with the permanence of physical attributes. The quoted dialogue emphasizes that while people often manage to alter their appearance or age through various means, they cannot change intrinsic characteristics like the height of a mountain. This symbolizes a broader commentary on human nature and the limitations that exist despite our efforts to reinvent ourselves.

The conversation highlights the idea that, unlike age, which can feel more malleable, certain truths and realities remain unchangeable. The metaphor of the mountain serves as a poignant reminder that some aspects of existence are fixed, representing stability in a world that constantly evolves. McCall Smith invites readers to reflect on the tension between our desires to reshape identities versus the acceptance of immutable truths.