All forms are impelled into motion by desire:—the bird and the animal roam land and air in their desire to secure food and shelter, or for the purpose of breeding, man is also moved by these desires, but has in addition other and higher incentives to spur him to effort, among them is desire for rapidity of motion which led him to construct the steam engine and other devices that move in obedience to _his_ desire. If there were no iron in the mountains man could not build machines. If there were no clay in the soil, the bony structure of the skeleton would be an impossibility, and if there were no Physical World at all, with its solids, liquids and gases, this dense body of ours could never have come into existence. Reasoning along similar lines it must be at once apparent that if there were no Desire World composed of desire-stuff, we should have no way of forming feelings, emotions and desires. A planet composed of the materials we perceive with our _physical_ eyes and of no other substances, might be the home of plants which grow unconsciously, but have no desires to cause them to move. The human and animal kingdoms however, would be impossibilities. Furthermore, there is in the world a vast number of things, from the simplest and most crude instruments, to the most intricate and cunning devices which have been constructed by the hand of man. These reveal the fact of man’s thought and ingenuity. Thought must have a source as well as _form_ and _feeling_. We saw that it was necessary to have the requisite material in order to build a steam engine or a body and we reasoned from the fact that in order to obtain material to express _desire_ there must also be a world composed of desire stuff. Carrying our argument to its logical conclusion, we also hold that unless a World of Thought provides a reservoir of mind stuff upon which we may draw, it would be impossible for us to think and invent the things which we see in even the lowest civilization. Thus it will be clear that the division of a planet into worlds is not based on fanciful metaphysical speculation, but is logically necessary in the economy of nature. Therefore it must be taken into consideration by any one who would study and aim to understand the inner nature of things. When we see the street cars moving along our streets, it does not explain to say that the motor is driven by electricity of so many amperes at so many volts. These names only add to our confusion until we have thoroughly studied the science of electricity and then we shall find that the mystery deepens, for while the street car belongs to the world of _inert form_ perceptible to our vision, the electric current which moves it is indigenous to the realm of _force_, the invisible Desire World, and the thought which created and guides it, comes from the still more subtile World of Thought which is the home world of the human spirit, the Ego.