recorded mention of the idea was in the 4th century BCE by Zhuangzi, and in Eastern philosophy, the problem has been named the "Zhuangzi Paradox." He who dreams of drinking wine may weep when morning comes; he who dreams of weeping may in the morning go off to hunt. While he is dreaming he does not know it is a dream, and in his dream he may even try to interpret a dream. Only after he wakes does he know it was a dream. And someday there will be a great awakening when we know that this is all a great dream. Yet the stupid believe they are awake, busily and brightly assuming they understand things, calling this man ruler, that one herdsman—how dense! Confucius and you are both dreaming! And when I say you are dreaming, I am dreaming, too. Words like these will be labeled the Supreme Swindle. Yet, after ten thousand generations, a great sage may appear who will know their meaning, and it will still be as though he appeared with astonishing speed. The idea also is discussed in Hindu and Buddhist writings. It was formally introduced to Western philosophy by Descartes in the 17th century in his Meditations on First Philosophy. Absent-minded transgression Dreams of absent-minded transgression (DAMT) are dreams wherein the dreamer absent-mindedly performs an action that he or she has been trying to stop (one classic example is of a quitting smoker having dreams of lighting a cigarette). Subjects who have had DAMT have reported waking with intense feelings of guilt. One study found a positive association between having these dreams and successfully stopping the behavior. Non-REM dreams Hypnogogic and hypnopompic dreams, dreamlike states shortly after falling asleep and shortly before awakening, and dreams during stage 2 of NREM-sleep, also occur, but are shorter than REM-dreams. Daydreams A daydream is a visionary fantasy, especially one of happy, pleasant thoughts, hopes or ambitions, imagined as coming to pass, and experienced while awake. There are many different types of daydreams, and there is no consistent definition amongst psychologists. The general public also uses the term for a broad variety of experiences. Research by Harvard psychologist Deirdre Barrett has found that people who experience vivid dreamlike mental images reserve the word for these, whereas many other people refer to milder imagery, realistic future planning, review of memories or just "spacing out"—i.e. one's mind going relatively blank—when