Soul in Life and Death are Different

 Moreh Nevuchim (1:70) The soul that remains after the death of man, is not the soul that lives in a man when he is born; the latter is a mere faculty, while that which has a separate existence after death, is a reality; again, the soul and the spirit of man during his life are two different things: therefore the souls and the spirits are both named as existing in man; but separate from the body only one of them exists.