[baudrunner]

The space with a vacuum is relative to a space with population. But its space is not necessarily devoid of anything because it still represents the potential for occupation.

A sheet of paper is still a sheet of paper even if it is a blank sheet. It can be filled with the depth of knowledge or thick with art and then it would constitute something in addition to the paper itself. That is what space is like.

The vacuum then is described as relative to that where gravity is an attractor to particles which populate it. The space is then occupied, whereas the space outside of the influence of gravity is only very sparsely occupied and we call that a vacuum. It's all relative.

It's like size. Size is relative. If we were a hundred feet tall then we would regard an elephant as being very small, like a mouse is to us because we think that we are normal and we draw the standard of size relative to our own size in the same way that we draw the standard of what constitutes a vacuum relative to what we call a liveable environment.