Perspective of Change

 

So you have climbed the mast of a sailing ship that is moving forward across the water at some given speed, say 20 miles between each hour "tick" of the clock you are holding. You drop a cannon ball to the deck. From your perspective relative to the boat, you see the cannonball drop downward to the deck in a straight line along the mast (the blue line in the illustration), producing a total change in position equal to the height of the mast . 

 But an observer on the shore does not see the cannon ball fall to the deck in a straight line. Rather the observer would see the cannon ball trace out a path in the shape of an arc (the red line in the illustration). And the the red arch that the ball traveled from his perspective is considerably longer than the blue straight line you observed from your perspective.

Yet, oddly enough, his clock on the shore ticked exactly the same NUMBER of "ticks" for the cannon ball to fall from the top of the mast to the deck of the boat which is at a different location when the ball strikes the deck as did your clock from the top of the mast when your the cannon ball fell in a straight line from the top of the mast to the deck. How can that be?

You are in good company. Galileo asked the same question some 500 years ago.

The answer is that your perceptive is one dimensional, ie the cannon ball changes position in a single direction from top to bottom of mast while the perspective of the observer on the shore is two dimensional, ie. the cannon ball not only changes position downward relative to the mast of the ship but also changes position sideways in the direction the ship is sailing, thus tracing out a long total change in direction. Yet, in reality, only a single event physical change occurred.

 What this informs us is that the perspective of your observation does not always reflect reality. You may indeed be seeing only one aspect of the totality of reality. 

Had the ship been sailing not only past the observer on the shore buy also away from the shore, the viewer's perception would be different because the observation becomes three dimensional; (1) up and down the mast, (2) side to side along the shore and (3) toward and away from the shore. And, indeed if the ship continued top move forward at 20 miles between each hour "tick" of the clock, the total reality would remain exactly the same for all three observational  perspectives!

Indeed, what you observe may not reflect the totality of reality but only one or more perceptions of reality. Newton viewed reality as being three dimensional -- having three and only three variables -- described above in the form of classical Newtonian physics. Then Einstein came along and added a 4th dimension -- fourth variable -- relative change of dimensions in the form of relativistic physics. Modern quantum physics as now grown to include a total 9 variable "dimensions" to reality, thus enabling numerous perspectives of reality.

As humans we are limited in our ability to make measurements of these "dimensions" with our five five primary senses. And we primarily live in a world of three "dimensions". But when we use our cell phone to track your progress as you sail along, the phone also uses Einstein's 4th dimension to more precisely track your path ... in your three dimensional world.