Can you summon a song in your head? A melody?
It's that.. But it's your voice. And you employ it to think. It's how I argue with myself and reason my way through a thing. I'm not sure how I'd get along without it, except every once in a while I get stuck on a problem, so I do something different. Often, the right solution to the thing I wanted to do will pop into my head. Then I need to work backwards how I got there. Both are useful, I prefer the information up front though.
The solution to this is to start your own instance and federate the other instances that you want to make sure you can always reach. This is a solved problem, really.