“As I recalled Bhagavan saying sometimes that unreal (mithya, imaginary) and real (satyam) mean the same, but did not quite understand, I asked him about it. He said, ‘Yes, I do sometimes say that. What do you mean by real? What is it that you call real?’
I answered: “According to Vedanta, only that which is permanent and unchanging can be called real. That is the meaning of Reality.”
Then Bhagavan said: “The names and forms which constitute the world continually change and perish and are therefore called unreal. It is unreal (imaginary) to limit the Self to these names and forms and real to regard all as the Self. The non-dualist says that the world is unreal, but he also says, ‘All this is Brahman’. So it is clear that what he condemns is, regarding the world as objectively real in itself, not regarding it as Brahman. He who sees the Self sees the Self alone in the world also. It is immaterial to the Enlightened whether the world appears or not. In either case, his attention is turned to the Self. It is like the letters and the paper on which they are printed. You are so engrossed in the letters that you forget about the paper, but the Enlightened sees the paper as the substratum whether the letters appear on it or not.
This is still more succinctly stated as follows:
The Vedantins do not say that the world is unreal. That is a misunderstanding. If they did, what would be the meaning of the Vedantic text: ‘All this is Brahman’? They only mean that the world is unreal as world but real as Self. If you regard the world as non-self, it is not real. Everything, whether you call it illusion (Maya) or Divine Play (Lila) or Energy (Shakti) must be within the Self and not apart from it.”
“The Teachings of Bhagavan Sri Ramana Maharshi in His Own Words,” edited by Arthur Osborne