“Further on we will give abundant proofs from ancient authors concerning this neglected truism. We will now only again assert that no spirit claimed by the spiritualists to be human was ever proved to be such on sufficient testimony.
The influence of the disembodied ones can be felt, and communicated subjectively by them to sensitives. They can produce objective manifestations, but they cannot produce themselves otherwise than as described above. They can control the body of a medium, and express their desires and ideas in various modes well known to spiritualists; but not materialize what is matterless and purely spiritual – their divine essence.
Thus every so-called “materialization” – when genuine – is either produced (perhaps) by the will of that spirit whom the “appearance” is claimed to be but can only impersonate at best, or by the elementary goblins themselves, which are generally too stupid to deserve the honor of being called devils.”
H. P. Blavatsky