During this sleep of the physical body the man is free to move about in the astral world; but the extent to which he does this depends upon his development.

The primitive savage usually does not move more than a few miles away from his sleeping physical form--often not as much as that; and he has only the vaguest consciousness.
The educated man is generally able to travel in his astral vehicle wherever he will, and has much more consciousness in the astral world, though he has not often the faculty of bringing into his waking life any memory of what he has seen and done while his physical body was asleep.

Sometimes he does remember some incident which he has seen, some experience which he has had, and then he calls it a vivid dream.

More often his recollections are hopelessly entangled with vague memories of waking life, and with impressions made from without upon the etheric part of his brain.

Thus we arrive at the confused and often absurd dreams of ordinary life.