"According to the Kabbalah (in the form expressed in hasidic literature), each man possesses two souls, one animal, the other divine.
The animal spirit is the vital force that gives life to the body, though it possesses, in addition, spiritual components that are oriented beyond this function and do not exist purely as ends in themselves.
The divine soul reflects the pure inner essence of humanity, its yearning toward the divine; it is unconnected to the body or its needs, which, indeed, it frequently overcomes.
It aspires to be and do good.
Every man's life is an ongoing struggle between these two souls, each of which strives to capture and dominate the individual."
–Rabbi Adin Steinsaltz
From The Tales of Rabbi Nachman, p. 85, by Rabbi Adin Steinsaltz