Why people ask it
Because they were handed a definition of faith — believing without evidence — that makes the answer automatic.
Short answer
Not on the biblical definition. The New Testament word means trust grounded in evidence, testimony and track record, which is how reasonable trust works everywhere else.
Deeper answer
Start by checking the definition, gently. If faith means believing things you have no reason to believe, then yes, that would be irrational — and Christians should agree rather than defend it.
The word used throughout the New Testament is pistis: trust or confidence, the kind placed in a person who has proven reliable. Jesus repeatedly points to what He has done and then asks people to trust Him on that basis. That structure is evidential.
This mirrors ordinary trust. You trust a bridge because of engineering, a friend because of history, a pilot because of certification. In each case the commitment exceeds what you personally verified, but it is grounded rather than arbitrary. That is what Christian faith claims to be.
Common mistake
Saying "you just have to have faith" when you cannot answer. It confirms exactly the caricature you were trying to correct.
Conversation-ready response
""Can I ask where you got that definition of faith? Because it is not the one the Bible uses, and I want to make sure we are arguing about the same thing.""
Source notes coming soon.