I'm changing the focus of this blog. Starting with this entry, I will be exploring the nature of truth and reality and the limited human capacity to perceive and understand them. The desire to comprehend reality as it truly exists, and to grasp its implication on our own existence, is something I call "veridicality".
Our consistent habit of standing and walking upright is part of what makes us unique.
But those are environments within our universe. We don't often think of what the very nature of our universe might mean for our adaptation. Here are some examples of how the physical nature of the universe, not our local environment affected our evolution.
1. Our perception of scale. We know, intellectually and from scientific inquiry, that the visible universe is about 28 billion light-years across, but that being able to know that and understand it are two different things. We have an innate understanding of distance at human levels. To say that the universe is 28 billion light-years in diameter, or about 1.64597995 × 10^14 miles, means nothing to most of us. We can understand numbers that large mathematically, but not emotionally. Explore this page to get an idea of how quickly human understanding crumbles in the face of very big or very small scales.
Similarly, we can't perceive things much smaller than a grain of sand, even though we have plenty of evidence that they exist, and can even take pictures of them.
2. Our perception of the shape of space. Similarly, space, on a human scale, is 3-dimensional. Not including time (which I'll get to later), space as it is understood by modern physics has a larger number of dimensions. We don't perceive those additional dimensions because they are "small" - a particle moving in one of those dimensions can't go very far, in fact such a small distance that we can't perceive it, though evidence of their existence can be found in quantum effects.
3. Our perception of time. Just like space, we can't emotionally understand time on scales much longer than a few human lifetimes, and we can't even perceive anything shorter than a few milliseconds in duration.
Our inability to experience the true nature of time goes beyond a poor grasp on scale, though. Albert Einstein is best known for discovering that time and space are related, and that both are relative to acceleration. This is general relativity. He also showed that acceleration and gravity are equivalent. This is called special relativity.
The curvature of spacetime, depicted as usual in two dimensions, because we can't even picture three dimensions being warped - let alone four dimensions being warped.
To say that time and space are related, however, is an understatement. It would be more accurate to say that they are the same. We don't have to believe that we live in a universe with multiple tiny dimensions that only affect us on the quantum level to believe that we live in a universe with more than three dimensions. We know beyond a doubt now that we live in a universe with at least four - the three physical dimensions that we perceive and time, which we experience as the passage of events.
The three physical dimensions are symmetrical - we can move forward and back, up and down, left and right. The fourth dimension, time, is simply another physical dimension, but it is asymmetrical. We experience it in only one direction, and we don't control our movement through it. It is because of this way that we experience time that we think it is essentially different than the other three dimensions. Our experience is that only the present actually exists - the past is only memory, and the future is something that may or may not occur.
Because relativity has been experimentally demonstrated, however, we know this is not true. Time is a spatial dimension, and it exists on a continuum. We think it "moves" in one direction because we only remember the past, not the future, but in reality there is no fundamental difference between the future and the past. Einstein himself recognized this conclusion, saying, "People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion."
The "persistent illusion" of time leads to a whole cascade of assumptions about the nature of reality that are, in fact, illusions. That cause precedes effect is an illusion, for instance. Causes are associated with effects, and because the dimension of time is asymmetrical causes orient toward the past while effects orient toward the future, but causes do not "happen" then make effects "happen", because time does not "pass". Rather, causes and effects are linked, but one can just as accurately say that effects lead to causes as much as causes lead to effects.
Dali's Persistence of Memory
These are just a few examples of how our scientific understanding of reality has far outstripped our innate ability to perceive reality. When we realize how fundamental our own built-in assumptions are, it shouldn't come as a surprise that these examples are just a scratch of the surface of how reality differs from our human perceptions of it. In the coming entries in this blog, I will explore more of these disparities between truth and human reality.