Man has never escaped from the thought that he belongs to two worlds; for some this is only a surmise, for others a joyful faith, but few can dismiss it for long. Life appears to be a scene with two panels; earth and heaven, seen and unseen – both are his. The one without the other is imperfect. If he has earth only, man is restless and hungry; if in his despair he forsakes earth, and flies to an antedated heaven, he deserts his team; he cannot be at peace; he is missing the distinctive gifts of this earth. Two worlds indeed are his, both mysterious, both inevitable, and somehow they are related. But how? Is there a ladder? 

What traffic is there between the two worlds?