“Enq: But why could not a man of well-balanced mind and singleness of purpose, one, say, of indomitable energy and perseverance, become an Occultist and even an Adept if he works alone?
Theo: He may: but there are ten thousand chances against one that he will fail. For one reason out of many others, no books on Occultism or Theurgy exist in our day which give out the secrets of alchemy or medieval Theosophy in plain language.
All are symbolical or in parables; and as the key to these has been lost for ages in the West, how can a man learn the correct meaning of what he is reading and studying?
Therein lies the greatest danger, one that leads to unconscious black magic or the most helpless mediumship. He who has not an Initiate for a master had better leave the dangerous study alone.
Look around you and observe. While two-thirds of civilized society ridicule the mere notion that there is anything in Theosophy, Occultism, Spiritualism, or in the Kabala, the other third is composed of the most heterogeneous and opposite elements.
Some believe in the mystical, and even in the supernatural (!), but each believes in his own way. Others will rush single-handed into the study of the Kabala, Psychism, Mesmerism, Spiritualism, or some form or another of Mysticism.
Result: no two men think alike, no two are agreed upon any fundamental occult principles, though many are those who claim for themselves the ultima thule of knowledge, and would make outsiders believe that they are full-blown adepts.
Not only is there no scientific and accurate knowledge of Occultism accessible in the West – not even of true astrology – the only branch of Occultism which, in its exoteric teachings, has definite laws and a definite system – but no one has any idea of what real Occultism means.
Some limit ancient wisdom to the Kabala and the Jewish Zohar, which each interprets in his own way according to the dead-letter of the Rabbinical methods. Others regard Swedenborg or Boehme as the ultimate expression of the highest wisdom; while others again see in mesmerism the great secret of ancient magic.
One and all of those who put their theory into practice are rapidly drifting, through ignorance, into black magic. Happy are those who escape from it, as they have neither test nor criterion by which they can distinguish between the true and the false.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 