Opinion
We take reality for granted. Philosophers, however, wonder what reality really is. The movie The Matrix did a wonderful job of expressing the question: “Is the reality I experience actually real?” The question famously led Descartes to examine the problem and, upon finding a solution, exclaimed, “I think, therefore I am.” Some jokers added, “I think, therefore I am -- I think.”
Physics concerns itself with the nature of reality, which seemed straightforward, following the works of Newton, who came up with a brilliant set of formulas that could be used to predict all kinds of motions, such as of an apple falling from a tree, a bullet emerging from a gun, and the planets traveling around the sun. Further, the formulas were brilliantly simple, and depended on time being consistently dependable, which we all knew it was.
Then Einstein came along, and screwed it all up. Time, he announced, was, under certain conditions, relative: it could change its speed. Gravity, too. No matter that nobody has yet figured out how gravity works, or time, for that matter.
The question of reality goes back to the times of Greek philosophers, who suspected there was more to our world than meets the eye. If there is stuff that we can sense (reality), then there really ought to be stuff we cannot sense (metaphysics), they surmised. They arrived at this point after realizing that the reality we sense is limited. Before I had my cataracts replaced, everything I saw had a yellowish tint to it; afterwards, it all initially seemed to have a blueish tint, until my brain got used to the new color system. Which coloration was the accurate one? Quite possibly neither.
We can go through a similar exercise with all of our senses. What I taste and smell is different from you. What I feel with my fingers feels different when felt by my chin. Our hearing is affecting by the amount of damage to the ear drum, hair cells, nerves. Philosophers jump on the truth that our senses are inaccurate in order to prove something or other. Nevertheless, we get through life.
Let’s go a step further, beyond having inaccurate senses. Let’s remove all properties of reality: no more texture, no more colors, no more sounds, no more taste, no more aroma. What are we left with?
Living In a Mathematical Construct
Mathematics, some physicists believe, is what we inhabit. In the world of CAD (computer-aided design), we are completely familiar with this concept. Our 2D drawings and 3D models are defined by mathematics. Here is one of the formulas used by CAD programs; this one defines the sphere (image source: Get Calc).
Formula for drawing a sphere
When you open a CAD drawing of a sphere, the program reads the data that defines the sphere’s center point and radius, and then reproduces an image of the formula on your computer’s screen. The Volume formula specifies the size of the sphere that you see, which is determined by its radius. The Surface Area formula is important for CAD systems, as they only display the surfaces of 3D objects, and not their insides.
You typically assign properties to the sphere, such as color, surface texture, material, and rendering mode. These make 3D objects look real on your computer’s screen, such as the material and rendering mode used to make this sphere look like the earth (image source: z0b's Realm).
Sphere made to look like the earth
Stripping away the sphere’s properties returns us to its formula.
So, if reality is defined by mathematics in a CAD-like fashion, what underlays mathematics? We dunno.
It’s Information, Innit?
A smaller group of physicists believes reality is defined by information. I won’t go into how they arrived at this theory, because it involves simultaneous states in quantum computing and the surfaces of black holes, which I barely understand. "Reality is actually information stored on the boundary of the universe." summarizes Jim Baggott in “Farewell to Reality.”
He uses the analog of holograms, those sheets of plastic encoded by lasers. When you project bright lights through the plastic, 3D images are seen by us. It’s the inverse of Plato’s cave: now, the shadows on the cave’s walls are the reality, and the 3D humans walking around outside are the illusion.
We have the same thing happening in CAD, when we store all known information about a building in a database or spreadsheet -- the 2D reality. When we import the information into a CAD program, it displays a 3D image showing the walls, balconies, windows -- the illusion of reality. (Image source: Snaptrude)
Importing a spreadsheet into a CAD program
So, if reality is defined by information in CAD-like fashion, what underlays information? We dunno.
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