For example, we have faith that the sun will rise tomorrow because we have a broad, solid experience of seeing the sun rise every morning (or for some of us, at least seeing that the sun has managed to make it up above the horizon again while we were sleeping). The “confidence quotient” of our faith is based on having seen and experienced that which we are putting our trust in.

A Jehovah’s Witness once posed this to me as an example of the necessity of faith, and I didn’t have the wit to point out that while it may technically be an article of faith, we also have the astronomical knowledge to know that failure of the sun to rise would be a rather extraordinary astrophysical event.

If I were to spend my life in utter ignorance of astronomy, told that some day the sun might not rise, I would no doubt be quite paranoid of that event, no matter how many times it was affirmed for me.