Why Knowledge, Logic, and Evidence Only Make Sense If God Exists
Without God, Knowledge and Evidence Would Not Be Possible
I’m going to say something that might sound extreme at first, but it’s a hill worth dying on: without God, you can’t have knowledge. You can’t make sense of evidence. You can’t even trust your own thinking. That might sound like a bold claim, but it’s where we end up when we examine what it actually takes to know anything.
This is what presuppositional apologetics is all about. I’m not arguing that God might be the best explanation based on evidence. I’m saying you don’t get to even use evidence unless God is real. You can’t account for logic, for reasoning, or for the idea of truth without Him. This came out clearly in a recent conversation I had with a former Christian who now identifies as an atheist.
Defining Evidence
He started by saying there’s no credible evidence for God. So I asked him what he meant by “credible.” He said it would need to be something that convinced him personally—something like a court case where you have to prove guilt beyond a reasonable doubt.
So I asked, “Are you the ultimate standard of credibility?” In other words, is your mind the final authority for what counts as true? Because if that’s the case, then it doesn’t matter what I say—you’ve made yourself the judge and jury, and you’ve already decided the verdict. That’s not objectivity. That’s just personal preference dressed up like epistemology.
Then he said he used to be a Christian. He’d read the Bible cover to cover, with dictionaries and study helps and all that, and decided it was fake. But that’s not the issue. The issue is: how do you know anything at all without God? Telling me what you don’t believe doesn’t give me a foundation for what you do believe.
Born Again or Just Playing Church?
I asked him if he had ever been born again. He said he got baptized a couple of times, but wasn’t sure what I meant by “born again.”
So I explained: being born again isn’t just joining a church or getting dunked. It’s about being made new. Regeneration. 2 Corinthians 5:17 says, “If anyone is in Christ, he is a new creation.”
Eventually, he admitted that maybe he hadn’t really been born again. Maybe he was faking it. And I said, “That actually lines up with Scripture. 1 John 2:19 says that if they go out from us, they were never really of us.” His own words validated the Bible’s categories.
Faith Is Not Blind Belief
Then came the common line: “Faith is just believing without evidence.” I had to push back. Where did you get that definition? Because it’s not in the Bible. Biblical faith is trust in the God who has revealed Himself. Faith isn’t a leap into the dark—it’s a step into the light of truth that God has already made clear.
Besides, if you’re demanding evidence, but you can’t explain why evidence should even matter, you’ve already lost the argument.
How Evidence Actually Works
So I laid it out: for evidence to be meaningful, we rely on things like rules of inference—if A, then B. A, therefore B. These are logical laws. They’re not physical. You can’t bump into them or find them in a lab. But they’re real. They’re immaterial. They’re universal. They don’t change.
I asked him, “Given your atheism, why do you believe those rules exist? Where do they come from?”
His response? “I don’t know. And I’m okay with that.”
But that’s not okay. That’s not an answer. If you don’t know why you believe in logic, but you use it to argue against God, then you’re sawing off the very branch you’re sitting on. You want to talk about evidence? Great. Then you need to explain how your worldview justifies using evidence in the first place.
Don’t Borrow What You Can’t Account For
Here’s the thing: atheism doesn’t give you the tools you need to make sense of the world. It just borrows them from Christianity. Logic. Reason. Morality. Objective truth. These are things that only make sense in a world created and upheld by the triune God of Scripture.
If you reject God but keep using His tools, that’s inconsistent. You’re leaning on a foundation you say isn’t there.
Atheism Isn’t a Neutral Position
Eventually, he tried to get out of the argument by claiming that atheism is just a “lack of belief.” He said, “It’s like not collecting baseball cards. That’s not a hobby. I just don’t believe in God.”
But I pointed out the category error. We’re not talking about hobbies. We’re talking about your view of ultimate reality. Saying “I lack belief in God” still has implications. You’ve still made a decision about the nature of reality—that it’s not personal, not moral, not created, not governed by a Lawgiver. That’s not neutral. That’s a worldview.
And if that’s your worldview, then you still need to explain things like logic, knowledge, ethics, and human dignity. And you can’t do that coherently without borrowing from the Christian worldview.
The Preconditions of Intelligibility
That’s what presuppositional apologetics is about. It’s not about meeting the unbeliever on supposedly neutral ground. There is no neutral ground. Everyone brings presuppositions to the table. The question is whether your presuppositions allow you to make sense of reality.
The Christian worldview does. Atheism doesn’t.
God is the necessary precondition for intelligibility. He’s the reason logic exists. He’s the source of moral law. He’s the one who upholds the uniformity of nature so science can function. And He’s the one who made you in His image, so you could know Him.
Take Him out of the picture, and everything else falls apart.
So What Are We Left With?
By the end of our conversation, the atheist hadn’t made a case for atheism. He couldn’t explain why he trusts evidence. He couldn’t ground logic or morality. He admitted he wasn’t really a Christian back then, and now he doesn’t know why anything is the way it is. He just knows he doesn’t want God.
That’s not an argument. That’s just personal resistance.
Romans 1 says that what can be known about God is plain to people, but they suppress the truth in unrighteousness. The evidence is there—creation, conscience, Scripture—but they don’t want it. It’s not a matter of needing more information. It’s a matter of needing regeneration.
So Christian, don’t be intimidated. When someone demands evidence, ask the deeper questions:
Why do you believe evidence matters?
Why do you trust your reasoning?
Where do logic and moral laws come from?
Why does a godless universe behave in a lawful, knowable way?
Keep bringing it back to Christ. Colossians 2:3 says that in Him are hidden all the treasures of wisdom and knowledge.
Without God, knowledge isn’t just unlikely—it’s impossible. But with God, you have a rock-solid foundation to stand on. And that’s an apologetic you can live by—and share with boldness.
🎥 Watch the Full Discussion
See the entire exchange that inspired this post and watch the argument play out in real time:
👉 https://www.youtube.com/watch?v=QakizukNjbA
📣 Pastors: Host a Defend Your Faith Weekend at Your Church
Want to equip your people to stand confidently for the truth of the Christian worldview? I’d love to come and lead a Defend Your Faith Weekend at your church. Visit our For Churches page to get the conversation started.