The concept of a time traveler:
Un uomo in una donna, anzi uno dioper la sua bocca parla,ond’io per ascoltarla
son fatto tal, che ma’ più sarò mio. (Michelangelo)
Some people think that when you break through and enter other dimensions you meet your ancestors or in any case some dead people or old souls. Terence McKenna was an advocate of this idea; also the shamans of the Amazon adhere to this notion. I have some other thoughts based on personal experiences.
I think these are your future descendants who you meet; they are time travelers from many centuries away. I have descendants, they will have their own, so some hundreds years later a young man will sit somewhere surrounded by transparent multiscreens. He will be fascinated by my art (I will be very famous in 500 years:), he is my distant descendant. As he is fond of me, he will decide to time-travel and visit me. The only possible way to do this without causing some damage or influencing the future (his present) is to enter my dreams. This is what he will do (and indeed does quite often). Being interested in my fate (and actually in the value of his inheritance as he owns quite a number of my pictures) he gives me tips how to draw better. These tips he gets from the old masters entering their dreams in the same way he enters mine.
In one of my dreams this week he finally revealed himself. Strange that they still have beards in 2519:)