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Step 2: The Importance of Relativity
Albert Einstein’s Special Theory of Relativity is a theory of the structure of spacetime and helps us understand (among other things) the relationship between space and time and between energy and matter. Relativity has required us to change the way we look at reality, but our application of this theory should not be limited to the relationships between space and time or matter and energy. One of the most overlooked and under appreciated insights to be gleaned from Relativity Theory is that it applies equally to all aspects of reality. As physicist Lee Smolin put it, “Our universe is nothing but an ever-evolving network of relationships.”(12) Our natural tendency is to think that an object exists in and of itself, independent of anything else. I exist whether or not you do. But a deeper understanding of relativity theory and objective reality shows us that there has to be something other than just the object itself. If a tree exists, it cannot be the only thing in existence – or it would not be a tree. The tree must have soil to grow in, sunlight to photosynthesize, water and CO2 to absorb and oxygen to emit. Its leaves are defined in part by the air they displace. The soil must have a planet to lie on, the planet needs a sun, and so on to the sum of existence. Each of those other things that also exist help to define the tree; and the more other things there are, the more precisely and completely the tree is defined. This is Relativity on its grandest scale and its most profound iteration. Because in a very real sense, without relativity, without the relationships that exist between the objects of the universe, nothing would exist. Relativity confers reality.
This seems an astounding assertion, but its truth should become clearer as we progress through this article. For the purposes of this discussion, what’s important is not the particular relationships relativity describes, for example, between space and time or between energy and matter. What is important is the fact of relativity itself. It is how relativity elegantly describes how the universe works and the very reality of the things that exist within it. It is the realization that things can only be characterized by their relationships with other things. And it will be the conclusion that these relationships are essential to the reality of any “thing.”
All things are in motion always. This motion has certain characteristics, among them direction and velocity. We know from relativity theory that the direction an object is moving only has meaning when described relative to something else. Usually, this relative position is wherever the describer is standing or perhaps the center of the earth. The point to understand is that at any given time, an object’s direction of motion is different relative to different points of reference. That object’s motion, then, is defined by the combination of two things: it’s own movement and by the particular point of reference.
This same principle of relationships applies to velocity of motion. Velocity can only be defined relative to a reference object (which itself will be in motion). A spaceship’s velocity relative to earth may be 17,000 mph; relative to a second ship keeping pace, its velocity is almost zero. The ship’s velocity thus becomes a function of it’s own activity plus it’s relationship with a point of reference.
Position in space (or time) follows the same rule. Classical or Newtonian physics describes a background canvas of space and time against which the position of any object could be calculated. Relativity theory, however, reveals that notion to be incorrect. Imagine trying to describe the position of a boat on the Pacific Ocean solely with respect to the drops of water it was sitting on. This would be impossible because the water is continuously shifting and flowing, constantly changing its own shape and the relationships of its various parts. The sensible thing to do would be to describe the boat’s location relative to other known objects – other boats, islands, landmasses, or even by the stars. Like the ocean, space and time are not static; they are ongoing processes that continuously “create” the universe in real time – there is no static background canvas (or ether) against which an object’s position in space or time can be calculated. Like the boat on the ocean, our spaceship’s position in this continuously evolving reality only has meaning when described relative to some other object’s position (usually, but not always, that of the describer). We can speak of the spaceship’s position relative to a certain star; we can also triangulate the position relative to two or more stars. It is the relationship that defines the spaceship’s position, which gives the reality of that characteristic. It’s also important to note that this dynamic between our spaceship and the star works both ways. The very act of defining the spaceship’s position relative to the star also defines the position of the star relative to the spaceship.
This principle of relationships actually applies to any characteristic an object can have. Size, color, weight, texture, all are relative traits, each a point along a continuum. Size is obviously relative; numbers we may assign, such as 50 meters, are arbitrary human constructs that allow us to recognize relationships between “larger” and “smaller.” (For that matter, numbers themselves are simply relationships made usable; individual numbers have no independent reality. The number “50” by itself means nothing; it’s meaning derives from its relationship with all the other numbers. It’s a little bit less than 51 and much more than 3.) Similarly, if I say our spaceship is blue, what I’m really saying is that it is greener than purple and more purple than green. “Blue” has no reality independent of the other colors of the spectrum. If all the universe were blue, blue would have no meaning. Any color derives its reality from it’s own character plus it relationship to the other colors of the rainbow. One might argue that the spaceship’s blue color was determined by actual photons each an actual wavelength which can be defined as “blue.” But this wavelength by itself has no meaning. It only has meaning in context of all the other wavelengths in the electromagnetic spectrum. If this “blue wavelength photon” were the only wavelength in the universe, there would be no such thing as either color or electromagnetic radiation.
There is no doubt that an existing object has it’s own characteristics. The essential idea to grasp here is that any object’s reality is determined by the combination of two factors: it’s own innate potential characteristics and the definition those characteristics receive from its relationship with the other objects of the universe. All things are defined as much by what they are not as by what they are. In fact, we could say that it is these relationships that give the object its reality. As said before, relativity confers reality. We’ll see just how fundamental this notion is when we talk about relationships in the world of quantum mechanics.
This principle of relationships does not apply only to objects, of course. Einstein famously established the relationship between space and time so profoundly he combined them into a single entity called spacetime. It would seem obvious that space could not exist without time, and there would be no time without space. What is less evident, but equally fundamental, is that space helps to define time and vice versa. As noted above, space is defined as much by what it is not as by what it is. Space and time give reality and definition to each other. So too with matter and energy. Einstein’s well-known equation E=MC2 establishes the intimate relationship between these two basic building blocks of the physical universe. Energy gives reality to matter and vice versa. Looking back at Hawking’s description of the early stages of the universe, we see how matter, energy and gravitational energy interact as building blocks of physical reality. Perhaps their relationship describes a self-perpetuating mechanism of the universe rather than a primal causality: gravitational energy begets energy begets matter begets gravitational energy. (For more on this principle of relationships, see sidebar: Are Attributes Absolute?)