Gurdjieff: A soul is a luxury. No one has yet been born with a fully developed soul. Before we can speak of reincarnation, we must know what kind of man we are speaking about, what kind of soul and what kind of reincarnation. A soul may disintegrate immediately after death, or it may do so after a certain time. For example, a soul may be crystallized within the limits of the earth and may remain there, yet not be crystallized
for the sun.
Views from the Real World p.87
Reincarnation is a very rare phenomenon. It is possible either over a very long period of time, or in the event of there being a man whose physical body is identical with that of the man who possessed these higher bodies. Moreover, the astral body can reincarnate only if it accidentally meets with such a physical body, but this can happen only unconsciously. But the mental body is able to choose.
Views from the Real World p.217
But the systems with which you are acquainted and which use this expression state that all men have an 'astral body.' This is quite wrong. What may be called the 'astral body' is obtained by means of fusion, that is, by means of terribly hard inner work and struggle. Man is not born with it. And only very few men acquire an 'astral body.' If it is formed it may continue to live after the death of the physical body, and it may be born again in another physical body. This is 'reincarnation.' If it is not re-born, then, in the course of time, it also dies; it is not immortal but it can live long after the death of the physical body.
In Search of the Miraculous p.32
What is the use of a man knowing about recurrence if he is not conscious of it and if he himself does not change?
Why should he make any efforts today when there is so much time and so many possibilities ahead-the whole of eternity? Why should he bother today? This is exactly why the system does not say anything about repetition and takes only this one life which we know. The system has neither meaning nor sense without striving for self-change. And work on self-change must begin today, immmediately. All laws can be seen in one life.
In Search of the Miraculous p.250