Ruach is the second level, and the Hebrew word means wind, breath and spirit, the same word used of the ruach elohim moving over the waters in Genesis 1:2. In the Kabbalistic scheme it is the moral and emotional soul, the seat of the impulse toward good and evil and of the capacity for choice, and it is generally said to be awakened rather than given, developing as a person begins to live a moral life. The Zohar and the classical Kabbalistic sources treat the three levels nefesh, ruach and neshamah as the principal scheme, and the medieval sources sometimes correlate them with the tripartite soul of Greek philosophy transmitted through Arabic and Jewish Aristotelianism, which is one of the points where Kabbalah and philosophy touch. Ruach is associated with Yetzirah, the world of formation.
Ruach's placement at Tiphareth, the sefirah read as the tree's own heart, harmonizing the opposed pillars of mercy and severity, is treated by commentators as fitting: the emotional soul is the seat of the middot, the moral and emotional attributes mapped in Kabbalistic ethical literature onto the seven lower sefirot from Chesed to Malkuth, and Tiphareth stands at their center. Later Jewish mourning custom also reflects a popular belief, not confined to Kabbalistic circles, that the soul's levels separate from the body in stages after death, ruach following nefesh; the graduated structure of Jewish mourning observance is often explained with reference to this staged departure, though the custom's roots are wider than any single Kabbalistic text.
Sources The ZoharTraditionally attributed to Moses de Leon with Tanya (Likkutei Amarim)Shneur Zalman of Liady, Major Trends in Jewish MysticismGershom Scholem