The Importance of Materialism

According to materialism, everything is made of matter and therefore there is no such thing as an ism. So why should I believe one set of ideas rather than another? Including the set of ideas that is called materialism. How do you go about cutting off the proposition that this need for something supernatural is but an extrapolation from nature? We may have some sort of need, but we choose to hypothesize as to something that goes beyond it that meets it in a greater way than nature.