Understanding different states of consciousness intellectually is one thing. Experiencing the phenomenon oneself is another. And once someone has had the experience it is very difficult to explain it to someone who hasn't. So, if you have already experienced or continue to live in a higher state of consciousness, try this way of explaining it to others. If you haven't, then see if this explanation is useful for your own understanding.
Awake, dreaming, deep sleep
We are all familiar with the first three different states of consciousness: deep sleep, dream sleep and being awake. And when we think about it, we also realise that when we are in one state of consciousness we cannot possibly appreciate or even recognise a 'higher' state.
Deep sleep does not allow us to know dream sleep. We are, to all intents and purposes, unconsciousness. In dream sleep, our reality is the content of the dream we are experiencing, and we do not know the waking state. However, in the waking state we can 'look down' at the other two states and recognize them as different states of consciousness.
The dream reality
In the dream state, we experience all sorts of happenings and situations. Some of these, the nightmares, are not pleasant. Other dreams can vary from joyous experiences to mundane ones, and everything in between.
While you're in the dream itself, that is your current reality. If anyone in your dream - perhaps a spiritual teacher - were to tell you that this is all an illusion created by your mind, you would wonder how they can make such a statement. And they might tell you that once you are 'awakened', you would see that all this (dream reality) is just a creation of your own thoughts, and that the real you is the witness behind it all ... and so on and so forth.
However, in that dream reality, such talk would amount to nothing but words to you. It would have no real experiential validity. In fact, you might dismiss it as being the teacher's own delusion, and you might wonder what this guy has been smoking.
Awakening to a different reality
When you wake up from a nightmare, or from a not-so-nice dream - and are now 'awakened' - you then realize: "Oh, that was only a dream. Thank goodness it was not reality! Now I am awake and all is well again in the real world." So, you get out of bed and start your day in the reality which is your life as you know it. And in that higher state of consciousness you now know, as a living reality, what that spiritual teacher was trying to convey to you when you were in the 'lower' dream state of consciousness.
Now ... the question is: Is this the real reality we're living? Or is this too only the reality of this particular state of consciousness? Are there perhaps higher states of consciousness beyond this one, where a different reality exists?