Remember this exchange from the 1984 movie Ghostbusters?

Q: Do you believe in UFOs, astral projections, mental telepathy, ESP, clairvoyance, spirit photography, telekinetic movement, full trance mediums, the Loch Ness monster and the theory of Atlantis?

A: Ah, if there’s a steady paycheck in it, I’ll believe anything you say.

It’s funny because, obviously, we don’t decide to believe things because of money. We believe things because we have good reasons to think that they are true.

I mean, if I told you I’d give you a million dollars if you would just believe that humans can fly, would that be enough to get you to believe it? You might say you believe it, but what if I asked you to prove your belief and visit the top of a cliff with me?

So we cannot choose our beliefs. They function at such a basic level that we can’t get behind them in order to change them.

Unfortunately, everybody since Adam (except Jesus) has had a sin problem that functions at an even more basic level than our belief systems. Because our beliefs stand on a foundation that has been corrupted by sin, we prefer autonomy over the kingdom of God. So unless the Holy Spirit acts on a person to overcome the effects of sin at this deep, deep level, trusting God just isn’t an option.

So where does evangelism fit in? Why evangelize people who can’t respond?

Well, it would be nice if people had a neon sign that floated over their heads, telling us whether the Spirit was stirring their souls, but it obviously doesn’t work that way. Instead, we should think of ourselves as instruments the Spirit can use however He pleases. God’s grace alone saves people, but our work of preaching the gospel is a means of grace God has appointed for reaching a lost world:

How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching? And how are they to preach unless they are sent? As it is written, “How beautiful are the feet of those who preach the good news!” But they have not all obeyed the gospel. For Isaiah says, “Lord, who has believed what he has heard from us?” So faith comes from hearing, and hearing through the word of Christ. (Romans 10:14-17, ESV)

That may mean my job is just to get people thinking — to show them that their most basic beliefs fail to explain the world they live in, or that there are good reasons to think that the claims of Christianity are true. (This is where apologetics is helpful, or as Francis Schaeffer called it, “pre-evangelism.”) Or my job may be to “close the deal” and lead somebody to repentance. The important thing to remember is that however it plays out for any of us, our job is not to guarantee the outcome of our preaching. Our job is to preach the gospel, faithfully and truthfully.

After all, if I can’t change my own beliefs at the most basic level, how can I possibly change someone else’s beliefs? Thank God that preaching the gospel is less about the preacher and more about the gospel — and the God who authored it.

P.S. I’m just skimming the surface of some very deep issues here. The idea that “we can choose our beliefs” is technically referred to as “doxastic voluntarism” (just in case you want to dig a little deeper into this stuff).