"Reality is still shown to us like shadows on the cave wall."

That sounds like something Plato would say, but it is still just a verbal attempt to express something that is not in line with our daily experience.
It is expressed succinctly in this limerick.

"There was a faith healer of Deal
Who said, 'Although pain isn't real,
   When I sit on a pin,
   and it punctures my skin,
I dislike what I fancy I feel."

David Hume had a usually unnoticed little footnote in his explanation of how consciousness is all we can really prove.
   He said something like..(paraphrased) "Even though I am sure of the logical consistency of my arguments, I still must admit that I can't avoid the sensations I encounter as if they reflect a solid reality"



"Bishop George Berkeley is best known for his philosophy of subjective idealism, which asserts that reality consists only of minds and their ideas, and that material objects do not exist independently of perception." When Dr. Johnson, of dictionary fame, was reminded of this, his reply was famous:
"“After we came out of the church, we stood talking for some time together of Bishop Berkeley’s ingenious sophistry to prove the non-existence of matter, and that every thing in the universe is merely ideal. I observed, that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it, ‘I refute it thus.'”(Boswell’s Life of Samuel Johnson, quoted from Wikipedia.)

These examples are only one way of approaching the idea of dreams, reincarnation, etc., having a reality of their own.