How can we know something is true?
Learn how evidence can justify belief even when absolute certainty is impossible.
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Begin with the basics: how arguments work and how evidence helps us decide what to believe.
Good reasoning still needs evidence. So before we ask whether God exists, we need to know what counts as a fair reason for believing something.
The crosswalk
A few blocks later, Jordan comes back to the larger question. “Even if we can test arguments, religion still feels different. People say something can be true for you and not for somebody else.”
You reach a crosswalk just as a car is coming. Jordan starts forward, notices it, and stops. You ask whether the car can be there for you but not there for him. He laughs. “Okay, obviously not.”
Then he shakes his head. “But that is a car. We can both see it. We did not see Jesus rise from the dead, and people disagree about religion constantly.”
As you cross, he says, “So how do we know what is actually true when we were not there to see it ourselves?”
Truth is about reality, not preference. We can know many things reasonably without having absolute certainty.
To weigh evidence for God or Christianity fairly, we have to be clear about what we mean by truth and what counts as knowing something. Otherwise, every disagreement can be dismissed by saying, “That is true for you,” which does not actually help us figure out what is true.
Truth, certainty, and historical knowledge
Truth is not whatever someone sincerely believes or whatever a group of people agrees to believe. A statement is true when it matches reality. A person can sincerely believe something and still be wrong.
For example, if one person says Jesus rose from the dead and another person says Jesus did not rise from the dead, both claims cannot be true in the same sense. One of them describes what actually happened and the other does not. That does not mean we automatically know which person is right, but it does mean there is a real answer to the question.
Another problem is the idea that we need absolute certainty before we can know anything. But that is not how we live. We know all kinds of things that we did not personally see. We rely on evidence, testimony, documents, memory, and inference every day. Testimony is simply information given to us by another person, and it can be good evidence when that person is in a position to know what happened and has reason to be trusted.
Philosophers call the reasons for believing something justification. Good evidence gives us good reasons to believe it. That is different from being absolutely certain. You may not be able to prove a historical claim in an absolute sense, but that does not mean you have no good reason to believe it.
Christianity does not need to be proven beyond every possible doubt before it can reasonably be believed. We should ask whether the evidence gives us good reason to believe Christianity is true. That is how we will approach the arguments for God and the historical case for Jesus.
Bottom line: Truth depends on reality, and we can reasonably know something without being absolutely certain about it.
Think about it: Why can you rationally know a historical event you did not personally witness?
Truth is about reality, and evidence can justify belief
You explain that belief and truth are not the same thing. People can sincerely disagree, but contradictory claims cannot both match reality in the same sense.
You also point out that most historical knowledge does not come from personally seeing the event. We use testimony, documents, physical evidence, memory, and inference all the time.
Jordan says, “That makes more sense than saying I have to see everything myself. I still want to know how good the evidence is, though.”
Use what you learned in a different situation
Someone tells you, “What is true for one culture may be false for another, so there is no objective truth.” How would you explain the difference between belief and truth?
The full course lets you write your response, compare it with a model, and track your progress.
Practice this inside the full courseQuestions this argument still has to face
“That may be true for you.”
If someone says something is “true for you,” first ask whether they are talking about a preference or about reality. Two people may be equally sincere about whether Jesus rose from the dead, but contradictory claims cannot both describe what actually happened.
“You were not there, so you cannot know.”
That is true, none of us was there. But none of us is personally present for most of the historical events we believe happened. We know history through testimony, documents, and other evidence. The real question is whether the evidence is strong enough to justify the conclusion.
Use this in a real conversation
- When somebody says, “That is true for you,” find out whether they mean a preference or a claim about reality. Those are very different things.
- Absolute certainty is usually the wrong standard. Most of what we reasonably believe is based on evidence strong enough to justify the belief, not proof beyond every possible doubt.
- It is fine to admit that you could be wrong. That is very different from saying nobody can know anything.
Do not claim more certainty than the evidence gives. The strength of our belief should match the strength of the evidence.
Sources for further study
- Biola | Introduction to Christian Apologetics: Explores objective truth, knowledge, and how evidence supports Christian belief.
- Impact Apologetics | Why I Still Don’t Have Enough Faith to Be an Atheist: Explains why contradictory claims cannot both be true and how to recognize self-defeating claims about truth.
- Stand to Reason | Is It Rational to Believe in God?: Discusses rationality, warrant, and Christian truth claims.
- Reasonable Faith | Foundations: Treats reason, evidence, worldview, and apologetic method before specific arguments.
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