How Faith Works: Why Knowing and Believing Are Not the Same Thing

https://youtu.be/bG9Ppx4Z2DM

Have you ever had that moment when you're boarding an airplane and logically, intellectually, you know that flying is safe? You know that planes take off and land every day without incident. You know that statistically, you are far more likely to be killed by a falling fridge than in a plane crash.

And yet, right at the moment the plane starts to take off, you get that jolt of fear. That spasm of panic. That voice in your head going: this is it, we're all going to die.

That moment reveals something really important: knowing something is true and actually, personally believing it are two completely different things. And that gap — the gap between intellectual knowledge and real personal belief — is exactly what this post is about. Because understanding how faith works means understanding what it takes to cross that gap.

This is part two of our Crash Course Catholicism series. If you missed part one, start here: What Is Faith, Actually?

How Faith Works: Faith Is More Than Just Reasoning

Maybe you've experienced this yourself. You've done the research. You've read the arguments for the existence of God, examined the evidence, weighed it all up, and intellectually, it all stacks up. You're looking at it going, "Okay, yes, this makes sense." But somewhere inside, you still find yourself saying: I just don't believe it.

That click hasn't happened. That lightbulb moment where understanding becomes personal conviction hasn't arrived yet.

So what's going on in that gap? And what does it actually take for Catholic faith to work, not just as a concept, but as a lived, personal experience?

Faith Begins With God, Not With Us

The first and most important thing to say about how faith works is that it begins with God. The Catechism puts it plainly in point 153:

"Faith is a gift of God, a supernatural virtue infused by him. Before this faith can be exercised, man must have the grace of God to move and assist him."

In the same way that we can't spark our own physical life into existence (we rely entirely on God for that) we also can't manufacture the spark of faith in our own souls. We can't think our way into that lightbulb moment. We can't will it into existence.

What we can do is prepare ourselves and stay open to it. And that starts with being able to honestly say: "God, I want to believe. I'm ready to believe. Please help me to believe.

The Four Elements of an Active Catholic Faith

To understand how faith works in practice, I want to use a metaphor. Imagine you have a friend who has never been to the ocean. Maybe they're housebound and never will go. And they're not sure the ocean even exists.

So you go to the beach. You fill up a bucket with seawater, grab some shells and some sand, and you take all of this evidence to your friend. You say, "Look: taste the water, it's salty. Feel it, it's cold. Here are the shells. Here's the sand. I know this isn't the ocean, but it's a piece of it."

Your friend takes it all in and says: "Okay. I don't have the full picture. But there's enough here that I believe you. I believe the ocean exists."

Now let's break down what actually happened there, because a few distinct things are going on.

1. Evidence came first. Before anything else, you brought evidence to your friend. This is what the Church calls "motives of credibility." Faith is not irrational or blind. In order to make an act of faith, we first need to see that faith is reasonable, whether through evidence, through logical arguments, or through our own lived experience. The brain is in the room. It has a job to do.

2. The intellect was involved. Your friend didn't just say "okay, sounds fine" and zone out. He engaged. He looked at the sand, tasted the water, asked questions. True faith doesn't bypass the intellect; it goes through it. Faith and reason are not opposites. They work together.

3. The will made a choice. Your friend was presented with evidence that made sense. He analysed it. And then he freely chose to say yes. We can easily imagine a version of this story where the friend looks at all the same evidence and says: "I'm sorry, a massive body of water with ecosystems in it? I just can't accept that." The issue in that case isn't a lack of evidence. It's that the will hasn't assented. Faith is ultimately a free act of the will, and God gives us that freedom, which means we also have the genuine capacity to say no.

4. The source had to be credible. Now imagine the same scenario, but instead of you bringing the bucket of ocean water, it's your friend's older brother who is constantly pranking him. He brings the exact same evidence. And your friend just laughs and says, "Get out of here. I don't trust you." The evidence is identical. But the source isn't trustworthy.

God is the Most Credible Source

That fourth point about credibility is incredibly important.

The Catechism (p.156) says that ultimately, the reason we believe revealed truths from God is not just because they make intellectual sense (although they do) — it's because God himself has revealed them, and God cannot and will not ever deceive us.

Now, when I first read that, I kind of balked. Aren't we always told not to believe things just because someone told us to? Isn't that exactly what fideism is? Blindly accepting things because an authority figure said so?

Here's the distinction. The reason we don't just take anyone's word for things is because human beings are fallible. They can be wrong, and they can deceive or make mistakes. That's why we check sources, weigh evidence, and think critically.

But God is not a fallible human being. God, by definition, is Truth itself. He is the source and creator of all that exists. As St. Thomas Aquinas puts it: "Truth itself speaks truly, or there is nothing true." If we can't trust God to tell us the truth, then there is no truth at all.

So when it comes to the mysteries of faith like the Trinity or the Eucharist -- truths that we couldn't have arrived at on our own -- God is not just a trustworthy source. He is the source.

What to Do If You're Struggling to Believe

All of this leads to something really practical. If you're wrestling with a particular truth of the faith, if you've done the reading, examined the arguments, and still find yourself stuck, it might be worth asking a different question.

Instead of starting with the concept you're struggling with, start with your relationship with God. Ask yourself: Do I really believe that God is truth itself? Do I really trust what God tells me? Because that's the foundation everything else rests on.

And if you're not even sure God exists yet, there's a remarkably simple prayer for that too: "God, if you're there, show yourself to me."

That click moment, where knowledge becomes personal conviction, isn't something we can force or manufacture. It's something we receive and then freely respond to.

Next up in the series: what does it actually look like to live faith day-to-day? Spoiler: it's harder than it sounds.