Reincarnation

There is a radically different approach in different Jewish circles related to mysticism, reincarnation, and other realms of the spiritual world. This even holds true in connection with Midrashic literature.

The traditional Lithuanian approach is to downplay all of these subjects. They are not necessarily dismissed as nonsense, but there is a strong attitude that one should not even begin to try to study or try to comprehend what they are saying. This the way I was taught in the various Yeshivot that I attended.

The Sephardic Jews were always more into the mysticism and encouraged their students to study Kabbalah as a means towards getting closer to Hashem.
Similarly, the various Chassidic sects also study some of these very high spiritual texts. For example, Chabad Chassidut places great importance towards the study of “Tanya,” which has many very deep esoteric ideas.
The Alshich, who was a Kabbalist, taught the case of Yibum, levirate marriage, as a proof that reincarnation exists. This explains why the brother of a deceased childless man is obligated to take his wife in marriage. The son that she will bear, will perpetuate the name of the one who has passed away.

If there wasn’t reincarnation, how else could we understand the permission granted to marry one’s sister in-law, who was previously forbidden.

It must mean that this new son born of this special union will somehow live on as a type of reincarnation of the original deceased.

The Lithuanian approach would be to observe this Mitzva of Yibum without asking questions, and accept that it’s beyond our scope of understanding.

The other schools of thought might find it more beneficial to delve more deeply as to the meaning of this Mitzva.

We must understand that both approaches have validity. The common denominator between the two, is a genuine desire to serve Hashem faithfully and to do what is right and proper in His eyes.