Rusty at New Covenant relates a story about a pastor using an illustration in a sermon that turned out to be an urban legend. He asks the question:
Still, what concerns me is just how many people in the congregation, if told about the story’s lack of authenticity, would care? Would they be more concerned with whether the story helps make the point the pastor is delivering, or would they think that the story’s veracity is more important? Would people accept the story, simply because it made them feel better?
A story told as an illustration can be used for a couple of different purposes. I can use a story to illustrate a particular point I’m making. The parables of Christ, for example, don’t need to be true in order to serve the purpose that Christ was putting them to. There didn’t need to be any Good Samaritan or any man who fell among robbers in order for that story to serve His purpose. Nothing in the story provided proof for Jesus’ teaching there. The story was used to illustrate a point Jesus was making, and to use the hearers’ own moral judgment, judo-like, against them.
But the parables of Christ are never presented as factual stories. They are simply what they are- stories used to illustrate a point. A story like this will always be fundamentally unlike the issue at hand, in all ways except the relevant issue. A parable is basically an extended simile. If I say “My love is like a red red rose”, I am comparing two unlike things. A rose and a woman are unlike in most ways, except that they are both beautiful. This is the comparison being made. Likewise, the Christian walk is not much like a farmer’s field, except in this one way- some ground produces a great deal, and some ground, because of various obstacles, fails to produce at all. This is how we recognize similes, or parables- the things being compared are very different. The lessons of the Good Samaritan can be seen to apply to my moral sense, despite the fact that I may never be confronted with the same situation. Jesus is not at all like a door, or a vine, except in the narrow way that the comparison implies- Jesus gives us access; Jesus gives us life.
On the other hand, a story used as evidence of something is an entirely different matter. When Jesus refers to the fact that the Jews’ fathers ate manna in the wilderness and yet died anyway, the factual occurrence that He is referring to is fundamental to His point. If it didn’t occur, then His story makes no sense. Likewise when He provides as evidence for His Deity the fact that David calls the Messiah (who is the son of David) “My Lord”, the historicity of the occurrence is vital. How can the Son of David also be the Lord of David? Only if the Messiah is also God. But if David never said that, then Jesus’ point makes no sense.
The story that Rusty relates appears to be used as proof of something. The preacher is using this story to show the congregation that something like this can happen to them too, since it happened to this Olympic diver. This is not an illustration per se, but an example of the sort of thing he is talking about actually occurring to someone. It is therefore evidence that such things can occur. It is presented as proof of the saving power of God; proof that the Cross can save you from disaster; etc. These things are all true, but if the story did not occur, then it is not proof of those points.
Sadly, I think the answer to Rusty’s question is that many of the hearers would not care at all whether the story is factually true or not. They would, as you say, accept it because it made them feel better. It seems to me that to say this is to tacitly accept the postmodernist view of religion, that the important thing is the effect the message has on me, not its factual truth or falseness.