What is the difference between lucid dream and reality?
Not much, I suppose.
I've never been much into lucid dreaming, and I have heard a lot about it.
So I would understand it from a Buddhist point of view.
It's the brain giving rise to stimulus without resorting to the organs of the body to provide the stimulus.
So it could still be
an object of insight.
It can still be the framework within to develop insight.
Now, the problem that we might have is that the dream state is still an altered state
It's not a pure or a purely clear state.
And as I said, lucid dreaming is not something that I've gotten into, so I can't say exactly what's going on.
But if it's simply the case where the brain is producing the stimulus and the mind is in a clear and lucid state, then it's still possible to cultivate meditation based on it.
The direct answer to your question is that there is no difference.
Reality is reality.
Dreams of any sort are a part of reality.
The problem is not that.
The problem with them, or the difference with them, is the state of mind that is reacting or interacting with them.
Because an ordinary dream, the mind is in a befuddled state.
It's in a state that is bereft of mindfulness or devoid of mindfulness.
So it's unable to grasp the object.
unable to see clearly what's going on and winds up getting caught up in concepts rather than experiencing ultimate reality.