If one leaves out of account the lone effort at religious orientation made by Rabbi Shneur Zalman of Ladi and his school, the so-called Habad-Hasidism, Hasidism seems to have produced no truly original Kabbalistic thought whatever. However, this interesting attempt to arrive at something like a synthesis of Issac Luria and the Maggid of Meseritz, despite the fact that it stands alone, provides in fact the best starting point for our investigation. It gives a new emphasis to psychology, instead of theosophy, a fact which must be deemed of the highest importance. To put it as briefly as possible, the distinctive feature of the new school is to be found in the fact that the secrets of the divine realm are presented in the guise of mystical psychology. It is by descending into the depths of his own self that man wanders through all the dimensions of the world; in his own self he lifts the barriers which separate one sphere from the other; in his own self, finally, he transcends the limits of natural existence and at the end of his way, without, as it were, a single step beyond himself, he discovers that God is “all in all” and there is “nothing but [Them]”. With every one of the endless stages of the theosophical world corresponding to a given state of the soul—actual or potential, but at any rate capable of being felt and perceived—Kabbalism becomes an instrument the precision of which is not infrequently rather astounding. What gives the writings of the Habad-school their distinctive feature is that striking mixture of enthusiastic worship of God and pantheistic, or rather acosmistic [in contrast to pantheism, denies the reality of the universe, seeing it as ultimately illusory, and only the infinite unmanifest Absolute as real], interpretation of the universe on the one hand, and intense preoccupation with the human mind and its impulses on the other.
Gershom Scholem, Major Trends in Jewish Mysticism; Ninth Lecture: Hasidism: The Last Phase
