"Everything is good when it comes from the hands of the Almighty;
everything degenerates in the hands of man."
—Jean Jacques Rousseau, Emile
Not the least of the ironies of the modern age is that the more it pretends to rationality, the more it wallows in the irrational. In the last generation, one of the trends in modern intellectual history has been the exposure of the irrationalist roots and affiliations of those periods and movements that boast most loudly of the triumph of their rationalism. The late Frances Yates' work on the importance of Hermetic and occultist traditions in the Renaissance and James Billington's exposure of the occultist linkages of the radical Enlightenment and European revolutionary movements are well-known instances. This scholarship shows that what is usually dismissed derisively as the "occult" not only survives in the modern mind but actually permeates it.
The latter half of the 19th century also witnessed an "occult revival" that—though it manifested itself in a number of secret societies modeled more or less along Masonic lines and claiming to possess secret knowledge of a mystical nature as well as, in some cases, the ability to perform magical operations—was actually a resurrection of Gnostic ideologies of antiquity. The occultism of the period was in part a reaction against...