Faith is a measure of irrationality

[Tonus]

When does faith become stupid?

When it is improperly defined.

In Hebrews 11:1, Paul defines faith as the "assurance of things hoped for, a conviction of things not seen." The example of the person grabbing an umbrella when he sees indications that it might rain applies here, though I would substitute "expected" in place of "hoped for." If you have a friend who is very reliable, you will come to have faith in him when he agrees to something. If he says he'll pick you up tomorrow at 10am, you have faith that he'll be there.

The idea that faith in god doesn't require clear evidence of his existence, or even that it is incompatible with proof of same, is not what Paul was talking about. After all, in verse seven he says "By faith Noah, being warned of God concerning things not seen as yet, moved with godly fear, prepared an ark to the saving of his house." Noah had direct evidence of god's existence and received specific instructions on what to do and how to do it. So where did faith come in? In that he trusted that if god said he would flood the Earth, he would do so.

As far as I am concerned, if you need faith to believe that god exists, then you're doing it wrong.