|Date: Thu, 11 Mar 2004
Basically the light that reaches our eyes (or telescopes) has a unique characteristic: In other than highly nonlinear situations, light waves will pass right through other light waves without distortion or interaction.
When the situation is highly nonlinear, light waves do interact with each other, as governed by the rules ("laws") of nonlinear optics.
Fortunately, in empty space the nonlinearity of the fluctuations "averages out to zero" on the whole. So a great percent of those "light interactions" in space average out (macroscopically) to zero. That means that the original "information" can and does get through to us.
The part that does not average out to zero on the initiating (transmitting) end gives us the ability to "see" the distant objects, their structures and characteristics. I.e., it is precisely those "nonzeroing interactions" that lets us observe "objects and entities" and their characteristics.
The part that does average out to zero along the way through the "transmitting medium" gives us the ability to still have good representations of those distant "nonzeroed" light entities that were originally transmitted.
Thus, by using both opposites (light interacts with light in certain cases, and in others does not interact with light), we are able to deeply observe our universe around us.
In nature, usually for a fundamental question with opposite answers, both opposites will apply sooner or later. Nature has a nice little habit of "not leaving anything out" and not forgetting anything. The reason we do not normally understand this "accursed necessity for the identity of opposites" (as the frustrated Aristotelian-logic philosophers referred to it) is that it is due to a flaw in the Aristotelian logic we are all taught. The logic is taught as "absolute", which nothing is. When perception or observation are added in as requirements, then five laws of logic are necessary rather than Aristotle's three. As an example, the statement that "A is not identical to not-A" assumes absolute knowledge (absolute observation), which does not exist. When observation or perception is inserted, the statement becomes "what is perceived as A and what is then perceived as not-A follows only after the two successive perceptions are compared, and difference is perceived. If the perceiving function or system is altered so that it is unable to distinguish the difference, then to that perceptual operation the former "A" is now perceived as identical to the succeeding former "not-A". That is, to two different observers, the same phenomena can be observed quite differently. Relativity, e.g., deals with this specifically: Observer A can see two entities as precisely the same, but observer B can see them differently; in fact, to observer B, one of the entities may not even have been born yet, and thus may not "observably exist". To really understand logic and what it's all about, one needs to read Morris Kline, Mathematics: Loss of Certainty. A serious reading of that book will forever alter one's notions of logic and physical reality (and whether or not mathematics is "ultimate truth" as so many mathematicians like to believe, or whether it is just a very good model and clever, useful game. Indeed, as foundations physicists such as Feynman have strongly pointed out, the physics of a situation is not in the mathematics at all, but rather is in the concepts and principles being manipulated by the mathematics.
Anyway, because of considerations such as the foregoing, we can indeed observe deeply into our universe, which means observing light that has traveled relatively unchanged for many billions of years. So we depend on the fact that nonlinear reaction does occur, to even "see" objects in the first place. However, we also depend on the fact that most of the nonlinear interactions thereafter "average out to zero in the macroscopic realm" so that we can thus receive the information from a vast difference, as in empty space. The tiny part that still does not average out to zero also tells us information about what happened along the way, such as the light passing through a "gravitational lens" enroute. With such lenses in the sky, we can "take a picture" of a single object seemingly in two different positions at once, e.g., as seen by light passing through the lens and as by light not passing through the lens. But then that comparison itself reveals the gravitational lens, which gives us even richer information and also some information about what interacted "along the way".
That is it is the true picture of what was