People sleep and have dreams. The dream world exists. It was almost the future world. Who is the self in a dream
 
Anyone who dreamed of the sinking of the Titanic stopped boarding. The dream self was someone else. I visited a place for the first time. I saw it in my dream decades ago. It's a dejabu. This dream self is myself. Is the self in the dream ownself or another? Which one?
 
How to find someone in a dream
Radio technology has developed in Japanese underground society. Person remember his body in his dream. The scientist then emits radio waves to the part of his brain that recognize his image and detects the reflected waves. The scientist gets the person's frequency from it. The scientist examines it. Ask your Japanese friend for details.
 
Prepare a dreamer, radio device.
1, A dreamer remembers himself in his dream.
2, At that time, the researcher examines he.
3, The researcher finds out who was it.
 
In the dream the self is either ownself or someone else. This is my guess. About 40% of dreams are dreamers ownself. 60% are someone else (same sex).
 
Summary
Most of the self in dreams are the ownself or an another person.
 
If you dream of a car accident, suicide or an earthquake, don't worry. Anyway, the half of it is the future of others.