As many long-time followers of Metaphysics of Physics will know, we take issue with certain aspects of modern physics (for instance we talk about that here). That includes many of the central assertions of General Relativity(GR).
Key among these is the assertion that space and time are mathematical dimensions which are also somehow an aspect of physical reality. That they are somehow unified into some mathematical abstraction known as “spacetime”.
But space and time or spacetime are not things. Which is how GR and this article treats them. If it did not the whole premise and conclusion of this “thing” called spacetime swirling around a dead star falls apart. And this is exactly what happens when we define space and time as valid concepts.
Space and time are abstractions. And abstractions do not swirl or twist or dance around anything!
And spacetime is an invalid abstraction in as far as it is treated as anything other than a mathematical technique.
What is Space?
Space is a concept which indicates relationships between positions. Meaning?
Suppose that we consider one of the rooms in our house, say the living room. The living room is that part of the house between the four walls of the living room and between those four walls is some “space”.
The “space” within that room simply indicates relationships between the positions of those four walls. One wall is over here, another wall is over there and the other two are other there and there. In between is all this space. The space essentially refers to the separation between objects. This “space” then forms some area or volume in which you can find things.
The space in this room is simply a sum of places. Space is simply the relationships between boundaries of some kind of container or some otherwise defined set of bounding objects.
So, for instance, you can walk into the living room and say “Well, we have these walls. They are in different positions. There are other positions in between them.” And the sum of those other positions is the “space” inside the room.
(You can find more in episode twenty-one of the podcast, where this section was derived from).
What is Time?
Time measures motion or change. For instance, it takes two motions or changes and identifies a relationship between them.
For instance, suppose we are talking about how old I am. What fact of reality does my age refer to?
Well, we take two events, my birth and the writing of this article. And identify the fact that there is a certain relationship between these two. My birth happened during a particular revolution of the Earth around the Sun. This moment is occurring within a different revolution of the Earth around the Sun.
While I write this, 37 such revolutions have happened. And so I have thus identified a relationship between my birth and the writing of this article.
I could do something similar with myself starting a race and ending it. Except, presumably I would use a second to measure the relationship between the start and end of this event; a second as measured by the motion of a second hand around a clock or by a digital equivalent.
Or suppose I wish to measure how long it takes me for me to grow larger muscles and be able to work my way from bench pressing 100 to 125 pounds. And suppose I track the time using the date on my phone.
What am I measuring here? Relationships between my strength levels, a change in such over time.
(You can find out more about time in this subscription article).
We will go into what space and time are only far enough to see that they are abstractions. They are measurements of relationships.