Is there any belief system which is not based upon a faith commitment?

There are times when people who are not religious accuse religious people of having "blind faith." But don't all systems of thought require some kind of faith commitment? Doesn't everyone accept a set of foundational umptions by faith through which they interpret their perceptions and experiences? For example, if one believes that at the most basic level that "seeing is believing" then is he able to validate his belief by seeing it? Or is his acceptance of the proposition "seeing is believing" something which he accepts on faith?