A true conclusion is true despite the evidence, and we must have faith in the strongest evidence. That is to say–if something is true, it is true even if we never find out about it. There may be evidence we do not know about. But, if a person is going to hold on to beliefs with blind faith “in the teeth of evidence” as Richard Dawkins first said in “The Selfish Gene”—then reason (including smack-you-in-the-face revelation) is not going to persuade.
Faith in the strongest evidence is mere intellectual assent and means confidence or trust in the evidence, but lacking certainty. It is the sort of faith that is necessary before we can trust or put faith in another person.
Faith “that” a person exists, or intellectual assent to the evidence that a person exists, is different from putting your faith, or trust, “in” that person.
To do something in good faith, is to provide confidence or build trust—it is to tell the truth, it is to be genuine, to provide good evidence. To do something in bad faith is to betray confidence or break trust—it is to deceive, to put up a false front, false evidence. An example used by Sartre is that to refuse to choose, is a choice, and so is a choice made in bad faith.
Blind faith, belief supposedly without any evidence, is a form of bad faith. When a person exalts blind faith, they think they are exalting the sort of faith that puts trust in a person, when actually they are insulting the person by saying there is no evidence that they are trustworthy, and they are demonstrating their own gullibility.
Good faith, contrary to what Richard Dawkins would say, is never blind. It is confidence or trust in the evidence, but lacking certainty. Varying degrees of faith are always required in any sort of knowledge below omniscience, below certainty. Of how many of your beliefs are you really certain? Of the rest–what is your evidence?