Can we believe and not believe?  At first glance, this seems an impossibility, a paradox in the making.  If we look closer, however, we see that, in truth, this dichotomy expresses the essence of faith.
     Mark's gospel (chapter nine) describes an encounter between Jesus and a certain man whose son, sadly, had been suffering from demonic possession almost from the day he was born.  How this happened, we are not told, only that it had caused the boy and his father enormous hardship and pain.  Hearing that Jesus, whose reputation as an healer of extraordinary powers had by this time reached across the breadth of northern Israel, was in town, the boy's father approached him and asked for help.  If you can help, Jesus, if you can help in any way, the father said, please do so.
     "If I can help?" Jesus replied, wondering whether the father knew to whom he was speaking, namely, the eternal God come in the flesh as a human being.  "I can help you," he said, "if you believe."
     Flustered but entirely honest, the man responded, "I believe, Lord; help my unbelief."
     What are we to make of this?  The father believed, but he did not believe.  If the father had believed without any reservation at all, would he have needed faith, of any kind?  Faith is of course believing, as the writer of Hebrews 11 reminds us, in the substance of things hoped for, the evidence of things unseen.  The father believed in the basic fact of Jesus' divinity, or else he would not have asked him to heal his son.  And he had had eyewitness testimony of Jesus healing other people.  He believed the substance, he believed the evidence, but he didn't believe that such things could happen to him.  He had reached the boundaries of what he imagined faith to be.
     Jesus burst those boundaries.  He demonstrated to the father that faith is to believe, yes, but it is also believing in unbelief, and that in the face of faith, unbelief is entirely present, for it is the ground and impetus of faith.  We believe because we do not believe, because we understand that we in fact do not believe precisely because we do.