When We Dream About Something A Japanese word “夢” means “dream” in English. Like its English version, it can refer to both dreams that we have when we are asleep, and dreams we have for our future. Come to think of it, I think it’s strange because both English and Japanese allot the same word to describe the sensation occurring in our mind during sleep, the aspiration they have, and the things they desire. I was also surprised to find that I had taken this similarity for granted for a long time. Is this just a coincidence, or was there an indirect interaction between English and Japanese in the past? I think English speaking countries and Japan hasn’t interacted with one another until recently. One possible hypothesis is that this use of the word originated somewhere, say in China, and this idea spread along the Silk Road to both Japan and Western countries. Or is it universal phenomenon for humans to associate dreams in sleep and dreams for the future? My medicine textbook says that when we are dreaming at night, we are in a state called REM sleep. It is characterized by the β wave as can be seen on electroencephalography, which is the same wave that is observed when we are awake and open our eyes. It may be that in a dream, we see the ideal state of the world as if we were awake with our eyes open. It is fascinating to think about dream in this way.