This quote from Oliver Sacks beautifully encapsulates the fascinating adaptability and plasticity of the human brain. It emphasizes how our usual, unconscious sense of proprioception—the intrinsic ability to perceive the position and movement of our bodies—is not the sole means through which we navigate and interpret our surroundings. Instead, it can be progressively supplanted by visual mechanisms which themselves become automatic and reflexive. This transition hints at the brain’s remarkable capacity to compensate when one sense or modality becomes impaired or less effective, illustrating how interconnected and flexible our sensory feedback systems really are.

What resonates strongly here is the seamlessness of this substitution—both proprioceptive and visual feedback operate unconsciously, underscoring how much of human experience and motor function lies beneath our awareness. This reinforces the idea that learning and adaptation are ongoing, dynamic processes; as the brain integrates new inputs and refines its reflexes, our interaction with the world becomes more fluent and coordinated. The passage also evokes a sense of gradual transformation—not sudden, but unfolding "week by week"—reminding us that changes in perception or cognition are often subtle and evolve over time.

Given the source, this quote also invites reflection on neurological conditions and the body’s extraordinary capacity for adjustment. It celebrates the brain's surprising and resourceful strategies when faced with deficits, while also evoking profound questions about the nature of self-perception and reality. Ultimately, it’s a testament to human resilience and the deep sophistication underlying every seemingly simple automatic action.