I have been reading a lot of books and web sites on string theory. It all seems very interesting, all these extra dimension and so fourth. I was just curious, it is supposed that these extra dimensions could be real, I have yet to read how the first three dimensions that we take for granted in this universe are real physical things. I know that the term dimension is used in plotting locations and trajectories of objects in space on paper, but are they real physical things that exist in the real universe?
Thank you.
Steve
Here's how I see it.
Consider the concept of "distance". My house is a mile down the road from my friend's house. Does that "mile" have physical reality? No, it does not. The road between the houses does, of course. But the "distance" is merely a mental model I impose on the two houses, to describe where they sit in relation to one another. I could just as well use "a half-hour's walk" to describe the relative positions; that too is just a conceptual model (the walking is real, but using it to describe relative position is an abstraction).
I view our three physical "dimensions" in a similar fashion. Objective reality is hard for us to grasp unless we impose conceptual models on it that help simplify and structure it. Regardless of whether we use cartesian (X,Y,Z) coordinates, or cylindrical or spherical or anything else, we are just imposing a mental model onto the objective reality to help with our comprehension.
So, in my opinion, the answer to your question is "No", dimensions do not have physical reality. They are a tool for helping to understand, describe, and work with, reality. Those who claim that dimensions have physical reality are, in my opinion, confusing their mathematical models with the Universe they are trying to model.
Going one level higher, again in my opinion, God is the only One who is capable of comprehending the Universe without resorting to models. But that's my personal view of God; I don't expect anyone else to necessarily buy into it. And in any case, my view of God is necessarily just a model, too, since I cannot directly comprehend God's infinite nature, at least not today...