This question is extremely subtle: consider it attentively. This is a rational proof which we are giving, so that the wise may weigh it in the balance of reason and justice. But if the human spirit will rejoice and be attracted to the Kingdom of God, if the inner sight becomes opened, and the spiritual hearing strengthened, and the spiritual feelings predominant, he will see the immortality of the spirit as clearly as he sees the sun, and the glad tidings and signs of God will encompass him. Know that the power and the comprehension of the human spirit are of two kinds: that is to say, they perceive and act in two different modes. One way is through instruments and organs: thus with this eye it sees, with this ear it hears, with this tongue it talks. Such is the action of the spirit, and the perception of the reality of man, by means of organs. That is to say, that the spirit is the seer, through the eyes; the spirit is the hearer, through the ear; the spirit is the speaker, through the tongue. The other manifestation of the powers and actions of the spirit is without instruments and organs. For example, in the state of sleep without eyes it sees, without an ear it hears, without a tongue it speaks, without feet it runs. Briefly, these actions are beyond the means of instruments and organs. How often it happens that it sees a dream in the world of sleep, and its signification becomes apparent two years afterwards in corresponding events. In the same way, how many times it happens that a question which one cannot solve in the world of wakefulness, is solved in the world of dreams. In wakefulness the eye sees only for a short distance, but in dreams he who is in the East sees the West: awake he sees the present, in sleep he sees the future. In wakefulness, by means of rapid transit, at the most he can travel only twenty farsakha an hour; in sleep, in the twinkling of an eye, he traverses the East and West. For the spirit travels in two different ways: without means, which is spiritual traveling; and with means, which is material traveling: as birds which fly, and those which are carried.