Why is there space rather than no space? Why is space three-dimensional? Why is space big? We have a lot of room to move around in. How come it's not tiny? We have no consensus about these things. We're still exploring them.
Space can vibrate, space can fluctuate, space can be quantum mechanical, but what the devil is it? And, you know, everybody has their own idea about what it is, but there's no coherent final consensus on why there is space.
I'm a great believer in our ability to come up with the ideas necessary to solve the big questions. I have less confidence that we'll be able to find a consensus about which ones are right without experiment.