He was examining the eyes of a young male Mongolian idiot in order to prescribe corrective lenses. The idiot’s mother was there, acting as an interpreter. “How many dots do you see?” Billy Pilgrim asked him.

This scene illuminates the difference between seeing and understanding. Billy uses the manmade tools and techniques at his disposal to determine a prescription for his patient, but the patient comprehends little. All the prescription can really do is help the patient see more of Billy’s test dots. No matter how useful, sight is always limited by the subjectivity of the seer’s experience and by the difficulty of communicating that experience to other people. Even with an interpreter, one can never fully understand another person’s perspective.

[I]t was generally believed that he was a vegetable. There was talk of performing an operation on him later, one which might improve the circulation of blood to his brain. Actually, Billy’s outward listlessness was a screen. The listlessness concealed a mind which was fizzing and flashing thrillingly.

Billy’s condition, as described here by the narrator, speaks to the untrustworthiness of sight. Doctors base their diagnosis of him on their sight, just as he diagnosed his own patients using sight. Yet Billy’s condition exists as something other than what his symptoms indicate. Billy now finds himself on the receiving end of sight’s limitations, and this reversal calls into question everything else he has seen—like an all-seeing race of fourth-dimensional aliens, for instance. Billy’s unreliability as a narrator drives home the story’s overall sense of ambiguity about our memories of what we’ve seen, particularly when those memories are clouded by trauma.

Rumfoord was thinking in a military manner: that an inconvenient person, one whose death he wished for very much, for practical reasons, was suffering from a repulsive disease.

Here, Billy’s hospital bunk-mate Rumfoord refuses to believe that Billy is coherent and capable of thought, simply because he dislikes Billy. This deliberate ignorance speaks to the fact that sight can be a choice. Often, people choose not to see that which feels unpleasant. Vonnegut identifies this human tendency as the root of something far worse: the ease with which warmongers dehumanize their enemies to accomplish their own gains. The subjectivity of sight can be a deeply sinister force.

Billy Pilgrim had stopped in the forest. He was leaning against a tree with his eyes closed. His head was tilted back and his nostrils were flaring. He was like a poet in the Parthenon. This was when Billy first became unstuck in time.

Here, the narrator describes when Billy first experiences lapses in time when he closes his eyes, trying to shut out the awfulness of the battlefield. Though sight may be unreliable, this moment speaks to the danger of going through life with eyes shut. Billy tries to ignore what he sees, and that decision separates him from the natural flow of human life. However, this moment also illuminates the impossible quandary presented by war: To look away is to deny reality. Yet when confronted with such life-shattering sights as the bombing of Dresden, denying reality feels like a mental necessity.

Billy thought hard about the effect the quartet had had on him, and then found an association with an experience he had had long ago. He did not travel in time to the experience. He remembered it shimmeringly.

Here, the sight of barbershop quartet singers’ open mouths triggers Billy’s memory of his German captors at Dresden, gaping in horror at the destruction of their city. This flashback, triggered by the sense of sight, serves as the first time Billy fully recollects the Dresden bombing. Billy does not time-travel to the experience, implying that this memory is more credible and sane than his others, that Billy finally allows himself to see clearly, without cloaking his memory in denial or fantasy. He cannot change these awful events, but he must acknowledge what he’s seen.