I’d never heard of Anthony Magnabosco before, but I saw this on Twitter and am thrilled to interact with a question that opens up possibilities for discussion rather than shutting them down. Here’s what I would say:
The first thing you have to understand about this question from the Christian worldview is that everybody knows that God exists.
For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse. For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened. -Romans 1:19-21
Does that mean that I think atheists are lying when they claim not to believe God? Not at all. I just have a healthy respect for people’s ability to convince themselves of things they know to be false. I think we all agree, actually, that people believe what they want to believe – not what they should believe based on what they know.
So in fact, every single person on earth has good reason to believe in God because we all see creation, and we all bear the image of God. What’s more, there is no good reason not to believe in God.
Are there also poor reasons for believing in God? Yes, there are. However I think we get a clearer picture if instead of talking about good and bad reasons for believing, we talk about good and bad belief. There is a kind of belief in God that is not saving faith, but only a deception to the person who holds it. That’s because (and this may surprise you) what saves a person is not believing in God, but believing God.
“Abraham believed God, and it was counted to him as righteousness.” … That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his offspring—not only to the adherent of the law but also to the one who shares the faith of Abraham. -Romans 4:3, 16
Believing in God as a kind of intellectual exercise is of no value whatsoever. What people need, what I would desire for any person, is to know God personally. This kind of knowledge doesn’t come from rational exercise, but from God revealing himself directly to the human heart.
Simon Peter replied, “You are the Christ, the Son of the living God.” And Jesus answered him, “Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven.” -Matthew 16:16-17
“My sheep hear my voice, and I know them, and they follow me.” -John 10:27
You have received the Spirit of adoption as sons, by whom we cry, “Abba! Father!” The Spirit himself bears witness with our spirit that we are children of God. -Romans 8:15-16
The work of the Holy Spirit in the heart of the child of God imparts a certainty that is inexplicable. It’s not an audible voice (that would probably engender more doubt than certainty), or any describable sensation, but simply the assurance that God has spoken and his words are true. We shouldn’t be surprised at this. How would you describe sight to a blind person, or music to a deaf person? If you can’t do something that simple, would you expect me to explain to you how the Holy Spirit imparts knowledge of God directly to a human soul?
The result of this is that the reasons Christians give for their belief in God are all over the map. Some of them are really bad. But that’s ok. God’s salvation does not come by good epistemology. It comes by hearing his call and obeying his voice. It transcends human reason, and a person thus saved will never be able to be dissuaded of his faith, no matter how unable he is to defend it rationally.
Don’t take that to mean that Christianity is not rationally defensible. It’s the only worldview that is rationally defensible. Biblical Christianity offers the only coherent and consistent explanation for the world we live in. The proof of this is a task that the church has never shied away from, but knowledge of God is not limited to those who can win philosophical debates.
So to answer the question, if a person believes in God because he knows God, I would desire for him to also be able to offer a clear and winsome defense of his faith in obedience to 1 Peter 3:15. Obviously I would not want him to stop believing in God, which he couldn’t do anyway. On the other hand, if a person believes in God without knowing him, it’s all one to me if he continues in that or switches to something else. Lost is lost. Rather, my desire for him and for all is that God would “grant him repentance leading to a knowledge of the truth.” (2 Timothy 2:25)
“If you abide in my word, you are truly my disciples, and you will know the truth, and the truth will set you free.” -John 8:31-32