“It is a well-known fact to both mediums and spiritualists, that the more the former is passive, the better the manifestations; and every one of the above-mentioned phenomena requires a conscious predetermined will.
In cases of levitation, we should have to believe that this self-generated force would raise the inert mass off the ground, direct it through the air, and lower it down again, avoiding obstacles and thereby showing intelligence, and still act automatically, the medium remaining all the while passive.
If such were the fact, the medium would be a conscious magician, and all pretense for being a passive instrument in the hands of invisible intelligences would become useless. As well plead that a quantity of steam sufficient to fill, without bursting, a boiler, will raise the boiler; or a Leyden jar, full of electricity, overcome the inertia of the jar, as such a mechanical absurdity.
All analogy would seem to indicate that the force which operates in the presence of a medium upon external objects comes from a source back of the medium himself. We may rather compare it with the hydrogen which overcomes the inertia of the balloon. The gas, under the control of an intelligence, is accumulated in the receiver in sufficient volume to overcome the attraction of its combined mass.
On the same principle this force moves articles of furniture, and performs other manifestations; and though identical in its essence with the astral spirit of the medium, it cannot be his spirit only, for the latter remains all the while in a kind of cataleptic torpor, when the mediumship is genuine.”
H. P. Blavatsky