In Vladimir Nabokov's "Bend Sinister," the author contemplates the intricate workings of the human mind, posing the question of whether everyone experiences vivid memories or thoughts that suddenly resurface unexpectedly. He likens these moments to bubbles released from a memory-filled 'cell' in the brain, suggesting that such reflections can emerge even when one is focused on something entirely different. This phenomenon highlights the complexity of consciousness and the occasional dissonance between our active thoughts and unbidden memories.

As one prepares to sleep, the clarity of logical thought becomes blurred, leading to a state where one's genuine thoughts might be obscured. Nabokov illustrates this through the notion of two parallel trains of thought, intertwining yet distinct, racing alongside one another. This imagery emphasizes the unpredictable nature of our mental processes and how, regardless of our intentions, memories and subconscious reflections can emerge, reshaping our understanding of our thoughts and experiences.