"The history of the world is the history of the warfare between secret societies."
-Ishmael Reed, Mumbo-Jumbo
"Almost everyone who has written about secret societies has attempted a definition of what such a society is: yet no satisfactory description of the phenomenon has yet been attained. This is because there are so many variants surrounding the central fact of the existence of the society that what will identify one society will not fit another."
-Arkon Daraul, Secret Societies: A History
"Nothing is true. Everything is permitted."
-Attributed to Hassan Ibn Sabbah, Grand Master of the Order of Hashashin (Assassins)
Some people think that the Illuminati is an evil organization dedicated to the overthrow of world society. Some people think that they are trying to bring about world peace through personal spiritual enlightenment.
And they are both right. It depends on your perspective.
Many people tend to scrutinize the historical record to prove a chain linking such occult groups as the Illuminati, Free masons, Rosicrucians, Knights Templar, Assassins all the way back to Gnostic teachings of India.
They do this no less for the modern conspiracies and secret societies that we all know so well (How ironic. If it was really such a secret would they be making Hollywood movies about it? Or is that just another part of the conspiracy?)
Both the theorists and the debunkers will swear on a pile of "evidence" that they are right and the other wrong, but once again they are both right and both wrong.
History is incomplete and inaccurate because it's just the fragment of human memory which is not universal, but personal. It's the order in which these experiences are filtered through the human mind that defines for us what reality is. That's the real "secret".
Secrets (real and imaginary) will always hold fascination for people because they speak to us of our own psychology.