[The following is my answer to an accusation that I was calling Adventists "a bunch of dummies" in my essay found here http://jimmiles.hubpages.com/hub/What-Twenty-Years-in-the-Adventist-Church-Taught-Me]
"Delusion" doesn't mean "dummy."
If I believe something based on insufficient or faulty evidence, we can fairly say that I am ignorant. A new ad campaign by Amnesty International "has highlighted the unintended consequences of imposing the death penalty by focusing on a handful of prisoners who were eventually presumed innocent after death." (http://www.youtube.com/watch?v=o_Sy8jU6sS4). People within our justice system were operating under common beliefs about forensic technology as it existed up to their time. These people include forensic pathologists, attorneys, and judges-- people whose occupations require more than average intelligence and a degree of mastery of logical reasoning and the scientific method. They were no dummies.
These same intelligent people were ignorant of evidence (such as DNA testing, a more recent development in forensic technology), and sent innocent people to their deaths. Political views on the death penalty aside, it demonstrates forcefully how intelligent people pursuing a sincere and just cause can nevertheless be so wrong due to insufficient evidence that multiple safe-guards to error all failed to prevent wrongly convicted people from being executed for crimes of which they were innocent, allowing the real criminals to remain free. Intelligent people can be wrong, and deceived, and even deluded, and that is not a comment on their intelligence. Rather it is proof that it is important to pay close attention to all of the best available evidence, and to integrate it into your beliefs and behavior.
Using reason and evidence-based methods of improving our behaviors, we can improve ourselves and our society. Our justice system is better now that we have the new tool of DNA testing. If I become so attached to a belief system that I am resistant to contrary evidence (which makes it difficult to trust my belief system) then we can fairly say that I am deluded or deceived. It would be insensitive to say that I am stupid or "a dummy," terms which are judgmental of my intellectual ability. It would be inaccurate to equate the concept of ignorance with intellectual ability.
SDAs preach that Catholics are suffering under the delusions that Mary is the Queen of Heaven and that one man deserves the power and privileges of the Papacy. SDAs feel sincerely that their interpretation of the Bible allows no other conclusion about Mary and the Papacy, and that Catholics are either ignorant of the truth about the Bible or so strongly attached to their system that they are deceived about the Bible and that their beliefs about Mary and the Papacy are delusions. The SDA belief system motivates them to reach out to Catholics using their most powerful tools, Biblical preaching and Ellen White's writings. If we were to observe SDAs' behavior toward Catholics and conclude that SDAs thought Catholics were dummies or stupid, we would be making an unfair judgment.
I do not think I am being unfair when I suggest that the SDA church has such a strong attachment to their prophetess Ellen White that they cannot accept evidence that she was not a true prophet, or that they elevate her to such an equality with the Bible that she deserves the designation of cult leader, or that they falsely claim to adhere to the Protestant Reformation's principle of Sola Scriptura (the Bible and the Bible ONLY as the ultimate authority for faith and doctrine). They cannot accept any such evidence and remain strongly attached to those erroneous beliefs, therefore by any means necessary they will explain away contrary evidence in favor of remaining faithful to the belief system. Remaining faithful to a system of beliefs despite great and contrary evidence, for the sake of preserving the system as if it had some inherent value, is properly called a delusion. If otherwise reasonable, intelligent, wise, and resourceful people prefer the comfort of their attachment to a faulty belief system, they are not to be judged as stupid, but merely deluded.
At the risk of belaboring this, let me repeat: I do not believe that SDAs as a church or that any particular SDA deserves to be called stupid, or dummies, or in any way lacking in intelligence. In my essay, http://jimmiles.hubpages.com/hub/What-Twenty-Years-in-the-Adventist-Church-Taught-Me, I did not say such things, or imply them. I did use the term delusion, but the above is meant to explain why I feel I was correct in my terminology. I think there is hope in the idea of deception and delusion. There is no cure for stupidity, or "foolishness," according to the Bible book of Proverbs. However, as long as life lasts, there is always opportunity to change our beliefs after reflecting upon sufficient contrary evidence. If a person values the search for truth and wishes to avoid the dangers inherent in delusion, they should always be given the opportunity to make that kind of positive progress. If they value comfort and status quo instead of progress, they likewise should not be judged unfairly for that equally valid choice. And everyone should welcome reasonable challenges to their beliefs from time to time in order to have the opportunity to change, or to choose to remain the same.