Incredulity is the quality or state of being incredulous = disbelief. Such a big word applies to little old, seriously old, me. Synonyms: disbelieving, distrustful, doubting, mistrustful, negativistic (say it’s not so!), questioning, show-me, skeptical, suspecting, suspicious, unbelieving.
I Ching (Book of Changes) – is ancient Chinese text with 64 hexagrams, which is the number of possible combinations of six broken or unbroken lines that represent two primal cosmic universal principles, yin and yang. Six is curious because five would be the more favored number by Chinese. However, theories supporting six are reasonable if not solid. Those in tune with the tao (path or way) have deciphered meanings to come up with some good fortune-cookie wisdom, but little has changed world-wide. Much more than what one can learn in a book or two apparently requires extensive philosophical study.
Illuminati – was a secret society founded in 18th Century Bavaria with a political agenda which was to happen through subterfuge, secrecy, and conspiracy. Paranoid conspiracy theorists (PCTs) believe the Illuminati still exists. PCTs, and other similar groups, believe we are nearing the end of civilization as we know it. They are closely tied with religious fundamentalist and UFO/alien cult groups. If I named names, you would recognize some. What people believe is scary.
Intelligent design (ID) – is a process by which creationists attempt to stake a scientific claim to prove god exists and created everything. It is, of course, a metaphysical claim. Sadly, many people think that evolution and natural selection (and if you like, chance) disprove, or are attempts to disprove, god. While the arguments can be made, such arguments do not logically say that the existence of god is precluded by natural selection. Both are possible. A god could have designed natural selection. ID is weak despite its many advocates (see junk science).
Insanity – is when a person suffers from a serious delusion. When many people suffer from a delusion, it is called a religion. (Robert M. Pirsig)