@richrf,
The interesting thing about the mind, is that we can use it to imagine such ideas as an 11-dimensional reality.
We can imagine infinite dimensions, plot their dimensions on graphs, etc...
And yet the physical brain is merely 4 dimensions.
Now, in set theory if 'A' has something in it that is not in 'B'
then 'A' cannot be a complete subset of 'B'
So because mind is multi-dimensional, and brain only consists of 4 dimensions,
then it follows that the brain is a subset of mind.
So the dream is no less real than the physical world.
I can barely even begin to describe the exceptionally detailed nature of my dreams.
Strange places, with every little tiny detail as perfect as this world.
Not all my dreams are that clear, or at least I don't recollect them all as being so clear.
Its just that when I am there, even when I am aware I am 'dreaming', I still consider them to be real. Exact detail in the cobblestones. Unique architecture. Marvelous creatures : People sized goldfish, walking on long legs across inately designed bridges.
Often I have dreamt I was talking to the dead, and I am so surprised by what they say and do - just so unexpected, and yet authentic at the same time. I cannot see these dreams as not real. Though I do have more ordinary dreams which are clearly metaphoric messages from my own self - those dreams have a distinctly non-real quality to them.
I would say that more than half my life is in my dreams, and I regard a night where I do not remember at least one vivid dream to be an extreme rarity.
But I have been trying to explore this for most of my life.
Its quite deliberate, but does take years of effort to will oneself to do it.
I am a sucker for curiosity.