"All the fools and the learned wise men from the beginning of creation, who say
that the spirit of man had a beginning, prove that it must have an end; and if
that doctrine is true, then the doctrine of annihilation would be true. But if
I am right, I might with boldness proclaim from the house-tops that God never
had the power to create the spirit of man at all. God himself could not create
himself.
Intelligence is eternal and exists upon a self-existent principle. It is a
spirit from age to age, and there is no creation about it. All the minds and
spirits that God ever sent into the world are susceptible of enlargement."
Teachings of the Prophet Joseph Smith
by Joseph Fielding Smith, p354