And yet all are in a different state, in which each one moves his reality. 
is the highest state the truth? who determines the truth?

@aakom

> In ref to both @oendertuerk and @hartnell, before venturing towards an ultimate truth, it needs to be precisely worded - reminds me of the computer in Hitchhiker's Guide.

Two points for the HHGTG reference. I agree, it's a damn good idea to define the problem before attempting to solve it. With that said...

> So, if all we experience is our mind, is there any state of mind that is universal, something we can all agree upon

Define mind.
Define state of mind.
Make sure to define them definitively. ;)

> This is not dissimilar to Descartes' meditation, although the answer is different.

If you mean "Cognito, ergo sum" then that would be a statement, not a meditation. Sure, it's a statement that summarizes the conclusion of a long chain of thought but unless you know that chain of thought and how that conclusion was reached, then it's mmmm tricky. In other words, it's about as useful as 42 without the question. 

> There is a state of pure awareness (or consciousness) devoid of any other experience.

There is a BDSM squirrel that plays blackjack with it's friends deep in the forest of zanzabar. If you don't get my sarcasm, allow me translate: "Sure, if you say so."

> It is the ground state of consciousness.

Uh huh. hmmm..... go on...

> We don't usually notice it as our attention tends to focus on the phenomena generated by the mind, be they deemed external or internal (the mind doesn't seem to care).

Hmm. This is overly complex and getting pretentious.

>  It has various names, depending on the language of the texts, but the definitions show such words to be synonyms, and hence the experiences to be the same.

Full on pretentiousness achieved.

> How can one experience a kind of stateless state? 

One could imagine that a bullet to the head might do the trick.

Then again, I have to admit, that two other possibilities are possible here:

1. "stateless state" is pseudo-profound bullshit.
2. "stateless state" is something you don't really understand.

> What is interesting is that the state has no phenomena that one can point to, and yet the memory of the state remains - it is not a memory-less sleep, it is a conscious state. Indeed, if I was more skillful, and diligent, I should be able to extend such periods of consciousness - so-called sleep yoga claims to have techniques to achieve this.

It seems to me that you're just aping understanding of what happens when you enter a state without ready associations to reference it by while in other states. I'm not sure where you get the idea that there's something called "sleep yoga", especially since sleep is a primary metaphor in esoteric schools. Waking consciousness is regarded as a form of sleep. The point is to wake the fuck up.

(15 minutes of research later)

Well dammit, my first impression in the above paragraph was wrong.

What you're talking about is "yoga nidra",  which, from the very first sentence of the wikipedia article the plot thins considerably. 

> Yoga nidra (Sanskrit: योग निद्रा) or yogic sleep) is a state of consciousness between waking and sleeping, like the "going-to-sleep" stage, typically induced by a guided meditation.

In other words, it's hypnosis. Since a lot of people fear hypnosis,  hypnotists (points to self[1]) have a practice of referring to a "talking induction" as "guided meditation." 'Cause that's what guided mediation is: an induction and reading of some kind of script to the hypnotee.

If you're really into this, you would do better to find some crazy local individual who geeks out on this sort of thing to hypnotize you or otherwise just to look into self-hypnosis. Better yet, learn hypnosis yourself. It's not that difficult and really really fun if you learn from the likes of Richard Bandler, Major Mark, and Ross Jeffries. Especially Ross Jeffries.  :) 

[1] This is a hypnotist joke you won't get. I've included it to entertain myself as the butt of the joke is myself. :)