what is the meaning of “concentric rings round the world” in this context?
In his spiritual vision Davis saw an arrangement of the universe which corresponds closely with that which Swedenborg had already noted, and with that afterwards taught by the spirits and accepted by the Spiritualists. He saw a life which resembled that of earth, a life that may be called semi-material, with pleasures and pursuits that would appeal to our natures which had been by no means changed by death. He saw study for the studious, congenial tasks for the energetic, art for the artistic, beauty for the lover of Nature, rest for the weary ones. He saw graduated phases of spiritual life, through which one slowly rose to the sublime and the celestial. He carried his magnificent vision onward beyond the present universe, and saw it dissolve once more into the fire-mist from which it had consolidated, and then consolidate once more to form the stage on which a higher evolution could take place, the highest class here starting as the lowest class there. This process he saw renew itself innumerable times, covering trillions of years, and ever working towards refinement and purification. These spheres he pictured as concentric rings round the world, but as he admits that neither time nor space define themselves clearly in his visions, we need not take their geography in too literal a sense. The object of life was to qualify for advancement in this tremendous scheme, and the best method of human advancement was to get away from sin—not only the sins which are usually recognized, but also those sins of bigotry, narrowness and hardness, which are very especially blemishes not of the ephemeral flesh but of the permanent spirit. For this purpose the return to simple life, simple beliefs, and primitive brotherhood was essential. Money, alcohol, lust, violence and priestcraft—in its narrow sense—were the chief impediments to racial progress.