“Enq: But do you not believe in Spiritualism?
Theo: If by “Spiritualism” you mean the explanation which Spiritualists give of some abnormal phenomena, then decidedly we do not.
They maintain that these manifestations are all produced by the “spirits” of departed mortals, generally their relatives, who return to earth, they say, to communicate with those they have loved or to whom they are attached. We deny this point blank.
We assert that the spirits of the dead cannot return to earth – except in rare and exceptional cases, of which I may speak later; nor do they communicate with men except by entirely subjective means.
That which does appear objectively, is only the phantom of the ex-physical man. But in psychic, and so to say, “Spiritual” Spiritualism, we do believe, most decidedly.
Enq: Do you reject the phenomena also?
Theo: Assuredly not – except cases of conscious fraud.
Enq: How do you account for them, then?
Theo: In many ways. The causes of such manifestations are by no means so simple as the Spiritualists would like to believe. Foremost of all, the deus ex machina of the so-called “materializations” is usually the astral body or “double” of the medium or of someone present.
This astral body is also the producer or operating force in the manifestations of slate-writing, “Davenport”-like manifestations, and so on.
Enq: You say “usually”; then what is it that produces the rest?
Theo: That depends on the nature of the manifestations. Sometimes the astral remains, the Kamalokic “shells” of the vanished personalities that were; at other times, Elementals.
“Spirit” is a word of manifold and wide significance. I really do not know what Spiritualists mean by the term; but we understand them to claim is that the physical phenomena are produced by the reincarnating Ego, the Spiritual and immortal “individuality”. And this hypothesis we entirely reject.
The Conscious Individuality of the disembodied cannot materialize, nor can it return from its own mental Devachanic sphere to the plane of terrestrial objectivity.
Enq: But many of the communications received from the “spirits” show not only intelligence, but a knowledge of facts not known to the medium, and sometimes even not consciously present to the mind of the investigator, or any of those who compose the audience.
Theo: This does not necessarily prove that the intelligence and knowledge you speak of belong to spirits, or emanate from disembodied souls.
Somnambulists have been known to compose music and poetry and to solve mathematical problems while in their trance state, without having ever learnt music or mathematics.
Others, answered intelligently to questions put to them, and even, in several cases, spoke languages, such as Hebrew and Latin, of which they were entirely ignorant when awake – all this in a state of profound sleep.
Will you, then, maintain that this was caused by “spirits”?”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 