The universal cosmic fluid is, as it was already demonstrated, the primitive material element, the modifications and transformations of which constitute the innumerable variety of bodies of Nature. (Chapter X.)  As a principal element of the Universe, it assumes two distinct states: that of etherealization or imponderability, which can be considered its normal primitive state, and that of materialization or ponderability, which is, to some degree, consecutive of the first. The intermediary point between them is that of the transformation of the ethereal fluid into tangible material.  Even at that point of transition, however, there is not an abrupt change from one state to another, whereby we can consider our imponderable fluids as an intermediary condition between the two states (see Chapter IV, items 10 and following).

Each one of these two states gives rise, naturally, to special phenomena. Related to the second state  (materialization) are the phenomena of the visible world  [editor’s note: remember that matter as we know it is only a transformation of the Cosmic Principle, representing the transformation (imagine as a condensation or a lower degree of vibration) of the cosmic principle, to the point that it becomes the tangible matter of the material world that we know].  Related to the first state (etherealization) are the phenomena of the invisible world.  Some, the so-called material phenomena, are within reach of Science.  Others, referred to as spiritual or psychic phenomena, because of their special tie to the existence of Spirits, fall within the attribution of Spiritism.  However, as the spiritual life and the corporeal life are in constant contact with one another, the phenomena of both categories is often produced simultaneously.  In the state of incarnation, humans are only able to perceive the psychic phenomena that are tied to the corporeal life; those of the spiritual domain escape the material senses and can only be perceived in the state of Spirit.

In the state of etherealization, the cosmic fluid is not uniform; while still of an ethereal nature, it undergoes modifications so varied in type and more numerable, perhaps, than in the state of tangible material.  These modifications form distinct fluids which, in spite of originating from the same source, are all endowed with special properties and give rise to the peculiar phenomena of the invisible world.

Within the relativity of everything, these fluids have for the Spirits, which are also fluidic, an appearance that is as material for them as the tangible, material objects are for the incarnate, and they are, for the Spirits, what the substances of the material world are for us.  They manipulate and combine them to produce certain effects, just as humans do with their material objects, though the processes are not the same.

There, however, as it is in this world, only the most knowledgeable Spirits are able to comprehend the role of elements that constitute the world in which the find themselves.  The ignorant beings of the invisible world are quite incapable of explaining the phenomena that they witness and even contribute to in an automated manner, just as the ignorant beings of the Earth are unable to explain the phenomena of light or electricity, to explain how they are able to see and hear them.

The fluidic elements of the spiritual world escape the analysis of our instruments and perception by our senses- made to perceive the tangible material and not the ethereal material.  There are some that pertain to a means so different from our own, that we can only imagine them through comparisons as imperfect as the ones by which a person that was born blind would try to imagine colors based on theory.

There are other such fluids, however, that are so intimately tied with the corporeal life that, to a certain degree, they pertain to the earthly environment.  Without direct observation, their effects can be observed, as we observe the fluids (energies) of a magnet- fluids that have never been seen, whereby we can acquire knowledge about the nature of those fluids with some degree of precision.  Such study is essential, because it holds the key to an immensity of phenomena that can not be explained the material laws alone.

An absolute purity, one that we can not imagine, is the parting point [the original state] of the universal fluid; the opposite point is that in which it is transformed into tangible material.  Along the spectrum that runs between those two extremes, there are innumerable degrees of transformation.  The fluids that are closest to the point of materialization, the less pure fluids, consequently, make up what is referred to as the spiritual atmosphere of the Earth.    It is in that environment, where the degrees of purity are equally varied, that the incarnate and discarnate beings of the planet Earth find the materials necessary to meet the needs of their existence.   In spite of being so subtle and impalpable to us incarnate beings, these fluids are still considered to be of a dense, impure nature, in comparison to the ethereal fluids of the superior regions.

The situation is the same in relation to other worlds, only with the appropriate modifications to meet each world’s inhabitants’ physical needs of life.  The less material a life is in a given world, the less affinity the spiritual fluids have with the so-called matter.

The qualifications of the spiritual fluids as such is not totally correct since, by definition, they are always material, just more or less quintessential, and what can be classified as truly spiritual is only the soul, or the intelligent principle.  The fluids are given that denomination only in comparison and as a reflection of their affinity with the Spirits.  We could say that they are the material of the spiritual world, whereby they are called spiritual fluids.

Source:
Genesis- Chap 14, items 2-6
Spirits' Book- #21-36