Where do dreams come from, and why do Kazakhs never have bad dreams?

History knows many examples when in a dream brilliant works of painting, literature or music were invented.

But not only creative people can have great ideas during sleep. For example, the inventor of a sewing machine, an American engineer Elias Howe had a dream that he was surrounded by savages on a desert island. They pointed spears at him. The engineer in a dream noticed that the tips of the spears at the base have holes. The inventor immediately woke up and sketched such a structure of the tips. So the problem, on which the engineer thought for a long time, was solved. A needle appeared for a mechanical sewing machine, the look of which has not changed until now.