What you are alluding to are different observations of the truth. The concept of reference frames depends on the universality of the laws of physics, which by definition means that there can only be one version of the truth. By the time your reference frame catches up to another, the observations converge.

seer and seen are described from the vedic times. there is a third element called the enabler.

person, box, light all are required for the person to declare there is a box. I dont see a box is an observation which is correct for a visually challenged person or person in the dark. they dont become truth.

Yeah. Their opinions which they believe to be true.