Most would say Vulcans do not dream. Most would be liars. Adult Vulcans had the necessary control to rest without falling into what Terrans would call REM state. Children lacked the necessary Disciplines and dreamt, but rarely of anything truly vivid or illogical like most humanoids. Spock was different. When he dreamt his dreams were vivid and improbable, like the dreams of his human mother. And at that moment, he believed he was in such a dream.