The initiate has already accustomed the untutored understanding, which clings to the outer senses, to higher concepts of an abstract character. He is now able to see spirit-forms, stripped of their corporeal shell, in the half-light with which the dim torch of metaphysics reveals the realm of shades. Let us now, therefore, having completed our difficult preparation, embark on our perilous journey.

When it is in a state of inertia and rest, dead matter, which fills the universe, is, according to its own proper nature, in a single self-same condition: it has solidity, extension and shape. Its manifestations, which are based upon all these grounds, permit a physical explanation which is also mathematical; this explanation, when the physical and the mathematical are combined, is called mechanical. On the other hand, there is a type of being which contains the ground of life in the universe. Such beings are, therefore, not of the kind which enlarge the mass of lifeless matter as constituents, or increase its extension. Nor are they affected by lifeless matter acting in accordance with the laws of contact and impact. They rather, by means of their inner activity, animate both themselves and also the dead stuff of nature. If one turns one's attention to this type of being, one will find oneself persuaded, if not with the distinctness of a demonstration, then at least with the anticipation of a not untutored understanding, of the existence of immaterial beings. The particular causal laws in accordance with which they operate are called pneumatic, and, in so far as corporeal beings are the mediating causes of their effects in the material world, they are called organic. Since these immaterial beings are spontaneously active principles, and thus substances and natures existing in their own right, it follows that the conclusion which first suggests itself is this: these immaterial beings, if they are directly united may perhaps together constitute a great whole, which could be called the immaterial world (mundus intelligibilis).