Think of a donut. Think of a vertical plane through the donut. The plane has two disconnected circles on it. Imagine trying to move the two circles apart. They

Think of a donut. Think of a vertical plane through the donut. The plane has two disconnected circles on it. Imagine trying to move the two circles apart. They resist your effort because they are attached together through their three-dimensional structure. In one view of time (“eternalism”, roughly speaking) saying “there is no change” or “no interaction” between any particles in the universe would mean that in the fixed structure of the universe of which time is a dimension, everything is constant in the direction of that dimension. So the two statements become roughly equivalent.