"My Father's house has many mansions" means there are dimensions you do not remember visiting. I use the word "dimension", but that does not say accurately what I mean to say. There is no word for what I want to say.
It is like — only like — you have a house with a third floor you are not aware of or have forgotten (not aware of and forgotten are the same) — and then suddenly you open a forgotten door (you have an insight) and there are the stairs, and there are the other rooms, treasures there all the time, but hidden from your view.