No. Many of the best con artists can convincingly simulate sincerity. If they were sincere, by definition, they wouldn't be con artists.
A con is by definition a transaction in which one person knows something that the other person doesn't, something that's being deliberately hidden from view for the benefit of the con artist.
We are who we pretend to be.
For Jenny McCarthy to continue to believe what she claims to believe, she has to be either brain-damaged or lying. Oh -- or both.
> Does it matter what they really think?
Of course it does. An intelligent, mistaken person can be reasoned with, educated, presented with new evidence. An intelligent con man cannot.
> We are who we pretend to be.
Unrealistically cynical. The best way to derive mutual benefit from other people is to be exactly who you say you are.
"She/he is a smart, honest, kind, well-meaning, salt of the earth person. This is just not the kind of person would would lie about ______"
Ghosts. UFOs. Truthers. Vaccinations. I have heard a thousand times.
Smart people can be wrong. Honest people can be wrong. Smart and honest people can be wrong.
"She has to be either brain-damaged or lying" sets up a False Choice that will lead many people to believe the opposite to what you are (presumably) trying to argue.
The spirit of what I was trying get at (perhaps, too "cleverly") with "many of the best con artists are sincere" is that one should not take off your Mr. Skeptical Sleuth hat, just because the person in front of you seems both intelligent and honest. Focus on the quality of the argument. Focus on the quality of the evidence supporting the argument.
All true, and why we have science. But the Jenny McCarthies of the world are so egregious that such charities can't extend to them -- they've been given too many opportunities to access sources of information apart from themselves.
> Focus on the quality of the argument. Focus on the quality of the evidence supporting the argument.
Yes, but after several years of the same pattern, it dawns on you that the problem is not the argument, but its source.