This is the part I'm objecting to:

To move, you have to move to or away from ... well, from what? You'd have to say that you don't even get to use a word like "move" when you are the only body in that void.

You can move. You can have a delta v. You don't have an absolute position or velocity, but you don't need those to move.

I don't see any comparison to the pre-sleep state, this is a statement about the void, and it overreaches.

This is a metaphor breakdown because you pushed it too hard, rather than a real problem with the idea. In the ideal case you are a floating point, and you haven't got discrete parts of yourself to fling away, but of course that's an abstract step too far away for the target audience of this piece.

Reflections on Relativity [1] in fact does build up to a generalize concept of relativity (not just Einsteinian relativity) starting with points in an unknown space (building up to a concept of distance, rather than assuming such a thing), but it's a mathematical treatment of the problem rather than an intuitive one. And certainly not in words of one syllable.

[1]: http://mathpages.com/rr/rrtoc.htm , the part I'm referencing starts right off at 1.1.

I think I haven't made it clear enough what my objection is. In my opinion it is the article that pushed the analogy too far. It works great to show that you can't tell what is moving. But when the analogy tries to claim that you can't move, well, it's pretty much begging the question. Of course a floating point can't move, and it says nothing about physics. That's why I assumed some mechanism for trying to cause motion: you can't see if you failed if you didn't try.

I guess I wasn't clear (no sarcasm). My point is based on the idea objecting that an analogy doesn't stand up to being pushed "too far" isn't a useful one; analogies always break down when pushed too far. If they didn't, they wouldn't be analogies, they'd be explanations. Analogies are dangerous ways of thinking, but again, this is generally targeted at people for who that is all they have available.

The analogy is useful, I agree there. The problem is that the article first uses the analogy for something it fits, then uses the analogy again for something it doesn't fit. The conclusions drawn from the second use are invalid. I don't object to the analogy, I object to that second use.

I had the same objection as the op actually - if you wake up at "rest" with just yourself and a bed, and accelerated away from the bed, you can in fact know whether "you are moving" or "the bed is moving". It is because one of the two have only been in 1 reference frame, while the other has been in 2.

Basically the same issue as the twin "paradox". I can appreciate the assumption of a constant velocity on wake though, as a way to simplify the story.

I don't think you can accelerate in an empty universe - no speed, no speed difference.