The Many Perspectives of Nature
We see a single world, one based upon a very narrow range of conditions, and what is important for the sake of understanding nature's space and time measures (relativity), one based upon a very, very narrow range of speeds: slow ones (ordinarily). As a result, we see only a single, common perspective of the world, and (again, ordinarily) none other. It leaves us with the image of a 'single', all-encompassing reality, a reality unique to a single, fixed set of 'universal' measures alone, a physical reality with a single, all-encompassing, common set of distances and angles for mapping anything and everything, anywhere and everywhere, a single set of when's and where's, and none others but this single set alone. This singular image of reality that we utilize in everyday life 'seems' to match perfectly the single world that we find ourselves existing in. Unless we have a basis for imagining differently (to be clear, a basis for imagining more richly), we, perhaps unknowingly, limit reality's measures of space and time to this simple, single image. Nature, however, is never constrained by our lack of capacity to imagine it accurately, and indeed exists independently of the limitations of our imagination, despite any lack of capacity (or desire) on our part to imagine as richly as nature does (or, for the sake of understanding nature accurately, at least to try to imagine as richly).
This single world and its single set of measures we perceive constitute the geometry of what we might appropriately call our common-sense intuition. We depend tremendously upon our common-sense intuition and its corresponding single set of physical measures, for everything. Minimally, it is how we calculate the motion of our own human actions, and, because it seems to be so effective, it is also ordinarily (unless we understand more valid models, like relativity, for example) what we imagine nature using (for measuring, mistakenly believing that all measures are universal). Indeed, unless we have discovered otherwise, we can imagine little more than distorting the existing set, but only with respect to a more encompassing grander, absolute set. Again, unless we have discovered otherwise, we can hardly help thinking that what' we see and the corresponding distances and angles that we perceive is the way the world (which is to say, the way that nature) 'is', regardless of the vantage point applied. But, individual reality and single of measures that it incorporates no more representative of 'all' of reality's measures, than is what we observe individually universal to and for all. To understand nature accurately, specifically, to understand the relativity (which is the 'inseparability') of nature's space and time (and ultimately, its gravity), we must first ignore the construction of measures that normally provides, this being our common-sense intuition, so as to make room for a much better one, 'better, by virtue of being far more accurate.
According to science, and specifically, according to physical science (that is, physics), the measures of our single reality are not universal, nor can they be applied to the entire universe as whole. They are, in fact, just one set of valid measures, among many, many other equally valid (though not equally convenient) sets of measures, including the actuality of many simultaneous "nows" besides our single one. This fact introduces an extremely important point to understanding how nature really “works.” Different 'nows' (simultaneous moments when it is the same exact moment in time in every direction at any distance) dividing all reality between many pasts and many futures, with not a single one ever being universal, makes what is past and what is future wholly a matter of one's individual perspective. (Although it is not important here, it is noted that one's perspective is wholly dependent upon and altogether unique to one's motion. As one's motion changes, so does the set of measures applicable to space and time, which is what one's perspective is, change also.)
The local environment, that for which our common-sense intuition was selected to accommodate, ordinarily never includes anything other than very slow speeds (when compared to the speed that light travels) and very short distances (considering the immense distances existing in the universe, indeed, even within our very solar system); for that is how things ordinarily move in our world (the scope of space that we ordinarily perceive), slowly (even our fastest things move slowly when compared to light) and very, very near. As a consequence of most motion occurring near us and this motion always occurring at slow speeds (again, according to the speed of light), our common-sense intuition quite naturally leaves us equipped with a single absolute notion for the measure of space and time, distances and angles, as is appropriate, in a world where light moves millions of times as fast as the fastest other “things” moving (these 'things' always being anything that is made of matter). Because it moves so very fast, light allows us to 'see' these things made of matter while they move – or while they don't – using light, of course; as that is precisely what light does: it allows us to see the motion of matter, or the lack of it. In so doing, it leaves us with the illusion of a single, common perspective for the entire universe, shared by all existence everywhere, which is simply untrue.
For each of us, the individual inhabitants of this seemingly singular world, a single set of measures, a single perspective alone, is enough for our common-sense intuition to be satisfied that a single geometry accurately describes all of the geometry there is in the big universe, just as we might be convinced that our individual image of the universe encompassing its full extent; but, it does not even begin to, nor does or can anyone's. As a matter of actual as well as historical fact, it is logically (or, if you wish, physically) impossible to describe the measures of the universe using any single, fixed set of distances and angles, even locally, like in some of our smaller, commonplace appliances like a television set or computer, accurately enough for engineering anything using modern electronics. (A founding father of modern physics, a “giant” whose name is irrelevant, tried and failed.) To put it bluntly, nature, clearly and simply, irrefutably and unquestionably, cannot possibly correspond to a single, fixed, absolute set of measures, but instead, absolutely must correspond to many, as many as there are distinct motions in "the universe" (meaning its entire history, not just a small temporal portion of that history).
The single set of measures constituting our common-sense model of reality, unless it understands that time is inseparable from space and hence that, according to the Theory of Relativity, there are many sets of equally valid measures, many equally valid perspectives, not just one, is flatly less than representative of nature's measure. Nonetheless, to the end of perpetuating the motions of the living machine sustaining our conscious mechanism, less-than-representative-of-nature's-measures as it may be, this single perspective is ordinarily spectacularly effective – provided that it can be ignored for the sake of understanding nature's ways accurately. Most significantly, it can be acquired independently of any formal instruction, which us a feature far more significant to the holder's survival than is its ability to model electronics or gravity accurately.
According to relativity, conventional, common-sense intuition – at least the conclusions it would ordinarily make with respect to the universe's geometry – is (again, ordinarily) usually very flawed (except, of course for local motion of matter – ignoring electrons and particle accelerators). But, given a sufficiently open mind, this flawed intuition can correct itself and become incredibly insightful – that is, provided one is prepared to abandon altogether, embracing some of the most fundamental cornerstones of one's very thinking, for the sake of replacing them with new, more correct ones. This is what makes learning relativity the most important step in understanding nature, at its heart, in a true way. Ignoring our common-sense intuition is what makes learning relativity, though conceptually the simplest step, usually the most formidable obstacle onemust overcome in order to begin to understand nature in the deep and sound ways that science does. We must ignore that which we can hardly imagine not being true, in order to understand (ultimately as part of a larger picture) what 'is'. It is a step that one cannot elude, without eluding the understanding itself. Luckily, this is not as overpowering as one's conventional intuition might (again, ordinarily) imagine. All that is required is genuine willingness, and most importantly, an open enough mind – which introduces an absolutely critical point to successfully learning science accurately: if one feels that they are 'willing' to be open minded, yet unwilling to abandon their common sense for the sake of accurate learning, then they will find that they are simply not willing "enough."
In the next science article, we will explore in the simplicity of one dimension fewer than our own just "how" nature can have so many different perspectives (as a fixed set of measures), in what is this, our very, very single world. We will do this by learning the basics of relativity, and how, according to it, spaces and the perspectives that correspond to them "tilt" (and ultimately bend). How nature can have so many unique perspectives is very easy and simple to understand when seen as Einstein (the discoverer of relativity) saw them, but only provided that one has, as Einstein did, a sufficiently open mind! This is a must. If one does not, then such an idea as spaces tilting and bending will seem simply 'unbelievable', despite how real and enormous its actual impact upon our modern world, in the form of global positioning satellites, television, and space travel, just to mention three of the most obvious examples.