Here's a silly thought experiment. Its purpose is to demonstrate how all our knowledge, everything we comprehend, is achieved through relative comparison. It is to say, our entire existence is one of relative experiences. Enjoy!
Here's the setup. You are you, except now you are invisible or bodyless or whatever. You can see the universe though. The universe, for what it's worth, consists of a single thing: It is an infinite expanse of the color green. It is one shade, hue, etc of green. There is nothing anywhere any different. Ok?
Now, you have a son, it turns out. How about that? Your son is also invisible and he also somehow has complete command of the English language, and he can see. He can communicate his thoughts directly to you via telepathy or some such thing. Anyway, you want to tell him about the universe, since he has never experienced anything before at all, except he is intelligent, such as it is, and can communicate in English.
So, you say to your son "Hey Son! Let me tell you something." To which he replies, "OK Dad, what is it?" "Well, Son," you say, "see the universe here? Guess what? It's all green. That's all that it is." Your son stares at you, strange since you are invisible, yet you sense it somehow, but you don't know it for sure, he is invisible too, after all. Right. Now his answer is not surprising. "Dad? What is Green
?" This is a simple question, right? You answer "Green
is a color, Son. In fact, it's the color of the universe. Really, that's all the universe is. It's Green
Your son is puzzled. "Really? Hmmm... I don't understand."
"I guess it is hard to understand... and, uh, gee, I don't even know how to explain it. How about this: Green is the word for a particular wavelength of light. Ah, there it is. And in this case, it's the wavelength of light that permeates the universe." Now that must have helped, no?
"OK Dad, I guess, but what is wavelength
"Son, just look at the universe, it's not hard to do, there's nothing else to look at and you don't have any eyes to close, so the universe, which is one thing and everything, is Green
. I'm telling you, that's what Green
"Ok, Dad. That's kinda weird, but what do you do with it? What's it for?"
"That's a good question, I suppose it's here for us to look at."
"Really? That's strange, isn't it? What exactly is the purpose of looking at it?"
"You know Son, I'm not really sure about that one..."
And just then a miracle happens. Suddenly, right in front of what would be your eyes, if you had any, something wonderful appears. The universe slowly, but evenly, divides in half. A definite line forms down the middle of the universe, in which one side is Green, just as it has always been, and the other side is now pink.
"Wow, hey Dad! There's something different
about the universe over there!" See, there's the regular universe on that side, and on this side, the universe is different!"
"Yeah, Son, that's what I was trying to tell you. The regular universe is Green
"But then what's the other side over there?"
"Aha!" Now you've got the upper edge on the situation. "Over there, that's Pink
"Ohhhhhhhh. I get it. That over there is Green
, and on the other side, is Pink
. How interesting."
"Now why is the universe Pink
"Son, I'll tell you when you're older."