A rejection of Materialism

Atheists and materialists say that there is no justification for believing in spiritual and religious teaching, but if we take that from the other angle, there is no reason to believe in statements about the material world. We believe whatever statement is made about the material world until it is contradicted by some other information, so why shouldn't we treat spiritual knowledge the same way? If we take their argument to the farthest we would even have to reject things we see with our eyes because we have no experimental evidence that proves our eyesight is not an illusion. At that point we would have no reason for doing anything. If we believe in knowledge we must believe in all of it. If it requires experimental proof we have to reject all of it.