Its etymology is rooted in "breath" (similar to Biblical or Kabbalistic nefesh) and is common to virtually all archaic psychologies where the act of breathing was connected with life, animating otherwise lifeless object. Some Sufis consider under the term "Nafs" the entirety of psychological processes, encompassing whole mental, emotional and volitional life; however, the majority of Quranic-based Sufis are of the opinion that Nafs is a "lower", egotistical and passionate human nature which, along with Tab (literally, physical nature), comprises vegetative and animal aspects of human life. Ego may be assumed as an equivalent for Nafs in modern psychology.