"So let's set the record straight. Faith is not the opposite of reason. The opposite of faith is unbelief. And reason is not the opposite of faith. The opposite of reason is irrationality. Do some Christians have irrational faith? Sure. Do some skeptics have unreasonable unbelief? You bet. It works both ways."
In Is God Just a Human Invention? And Seventeen Other Questions Raised by the New
Greg Koukl on Faith, Reason & Rationality - Apologetics 315