Reincarnation is a fundamental belief in Jewish tradition. In Hebrew,
Reincarnation is called "gilgul ha'ne'shamot,"
literally the recycling or transmigration of souls.
This concept can be compared to a flame of one candle lighting another
candle. While the essence of the second flame comes from the first
one, the second flame is an independent entity. Still, the new flame
contains imperfections inherited from the initial flame, and it is
these imperfections that are to be corrected.
Most of the written material of reincarnation is very esoteric,
often written in Aramaic. Some of the prominent works dealing with
this subject are the "Zohar" (1st century) and
the Arizal's "Shaar HaGilgulim" (16th century).
In the Bible itself, the idea is intimated in Deut. 25:5-10.
Many sources say that a soul has a maximum of three chances in
this world. One example given is that the great Talmudic sage Hillel
was a reincarnation of the Biblical figure Aaron.
The soul only comes into this world in the first place in order
to make a spiritual repair. If that is not fulfilled by the end
of one's lifetime, then the soul will be sent down once again. The
return trip may only be needed for a short time or in a limited
way. This in part explains why people are born with handicaps or
may live a brief life. (Example someone who would continually bother
a cripple man, his fixing would be to comeback as a cripple man
and feel the pain)
It is not necessary that there be a conscious awareness in order
for the correction to take place. Conscious awareness is only one
level of understanding. This idea is explored in an interesting
book called "Psychic Phenomena," by Dorothy Bemar Bradley,
M.D., and Robert A. Bradley M.D.:
"Mentally retarded children have been known to burst out with
unexpected abilities under altered awareness, manifesting the contents
of the undamaged and theoretically undamageable unconscious mind."
In other words, there are levels of understanding that transcend
the conscious level, even in children.
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Truly, most"corrections" do not have to take place through
the body, but rather take place in the soul world, in the afterlife.
However, sometimes the correction must occur in the physical world.
For example, it may involve a certain challenge of choosing the
"right thing" over choosing the "comfortable thing."
Or other people may have to be involved. And the soul cannot interact
with the physical world in any other way expect through a body.
The bottom line in all this is that a person's life situation provides
everything necessary to achieve ideal growth. Our task is simply
to employ our free will -- i.e. to properly and effectively use
the opportunities that come up.