A sculpture changes as you walk around it, although the sculpture has not moved.

A sculpture appears to change while doing nothing at all. What moves is you, and every step alters the relationship between the form and your position, which means the object exists as a series of encounters rather than a single fixed image. Seeing it whole requires motion on your part.

Most things worth understanding work this way. A person, a problem, a decision looks different from a different position, and staying still guarantees a partial view. When you are certain about something, the useful discipline is to move: talk to someone with a different stake, read the case you dislike, wait a month. The object may not need to change for your account of it to.