In Tobias Wolff's "Old School," the concept of tropism is introduced as a metaphor for human aspiration. Just as plants grow toward the light, people naturally strive for their own forms of enlightenment and fulfillment. The idea suggests that rather than actively pursuing goals, one can create an environment that naturally draws them toward what they desire. This reflects a deeper instinct in humanity that remains unaffected by scientific explanation or analysis.

Wolff emphasizes that while science can illuminate misconceptions and distractions—representing false lights—it cannot extinguish the fundamental yearning for truth and growth that resides within everyone. The metaphor of darkening a room to guide a fly suggests that with the right conditions, individuals will gravitate toward their ideals and aspirations, simplified through the notion of leaving a 'crack of light' to guide them home. This speaks to the enduring nature of human ambition and curiosity.