Some religions maintain that the individual soul takes on numerous bodies until the goal of Self-realization is reached. The doctrine of reincarnation is commonly associated with Eastern mysticism, especially Hinduism, but did you know that the Fathers of the Church at the Alexandrian Council also discussed whether reincarnation should be admitted in their doctrines? They decided against including past and future lives and instead gave us Heaven and Hell. Although it is unfathomable that a soul could be created by God and then go on to enjoy or endure eternal life within pearly gates or in the flaming fires of the underworld. What is born must die, and this means the body.
The concept of reincarnation calls into question one's view of personal identity. If you view yourself as a complex of desires, inclinations, preferences, talents and personality, existing along a continuous thread of personal memories, then you only live once. As the philosopher John Locke said, "What is personal identity? It is just your chain of particular memories." Who were you before you had this name and form (a form which, by the way, is always changing, growing, aging, regenerating its cells, and finally decaying)? Did you go by your present name, or by the name you carried in some prior life? And who are you when you die? Do you keep your present identity until your immortal soul seizes upon a new body in which to abide? Who are you in between? You see how tricky the topic can become.
Let's keep it simple. I cannot remember who or what I was before this lifetime. In fact I cannot remember existing before my earliest memory (of nearly drowning), which happened around the time I was two. So this me, this mind, this personal identity, did not exist prior to my birth. And if that which always exists alone is, then this personal identity, fleeting as it is, cannot be said to really exist, in the absolute term. Any tendencies that people try to explain by saying, "It was from a former life" can be better explained in the present tense, as genetic and environmental factors go so far to influence a person's actions.
Of course, if you view yourself as pure awareness, identical with the Absolute which gives rise to this universe of names and forms and pervades everything, then you exist simultaneously everywhere, in everyone, since that beingness is at the same time backdrop on which the universe appears and force pervading everywhere. Awareness in everything. Therefore, you, in the Absolute sense, are incarnating in all names and forms, but in nothing in particular. And by identifying yourself with what truly is, you have transcended reincarnation. Which is likely what is meant when the sages say the cycle of birth and death ends once union with the divine is achieved. Once you've realized your oneness with the Absolute, source and substance of all that is, you sever identification with the one who is born and dies. And then the game is over. And victory is achieved.
Again, trying to explain personal circumstances in the present by past karmas in prior lives that you do not recall, and, since no ties of identity bind you to this hypothetical being, you cannot be really held responsible for, is escapism or masochism, depending on whether the circumstances you're attempting to explain away are favorable or infavorable. And if you stop living today in expectation of some future life of fame and glory, then you are losing the now for a then that will never come, because this you (mind and body) won't be there to enjoy it.
My dad, a staunch believer in the myth of reincarnation, recently said to me, "I don't care who I come back as in my next life, as long as it's not a woman." Sexist though this may be, my reply was, "It doesn't matter either way, dad, since that future person will not remember this present desire once the tie of identity is severed at death. Concern yourself with now, which is all we have, and which is everything."
See yourself as the consciousness that pervades everything and animates matter, the consciousness on which this world manifests. This gives meaning to the ages-old adage that all is one.
Express the delight of your being through love of others, knowing these others as appearances in consciousness are only reflections of the one, and whether or not you are born again in this life or in another (since there are multiple meanings of the term "to be born again") all will be well since you know who you really are.
Interestingly I had a curious experience the other day. I took a nap on the floor, and when I regained consciousness I didn't know who I was or where I was. I just was. It didn't last for more than a few moments, but in this period, which divorced from time was like forever, I was free consciousness. With no memories, mind, personal identity. This may very well be what life is like after death (and before) and what life is like for, dare I say, God. Who is just pure consciousness. How do you know that you're all that is? Does someone come and tell you? Of course not, or else you wouldn't be alone. Merging with God may just be returning to that essence of pure consciousness from which all arises and to which all returns. I'd take that over heaven or hell, or for that matter some future life as a sex symbol or starlet, any day.