The Theory Behind the Question
Let me ask you something simple. What do you actually know?
Not what you think you know. Not what you were told. What do you genuinely, without a doubt, know to be true?
It sounds like an easy question until you sit with it for a moment. Then it starts to get slippery.
Philosophers have been wrestling with this for centuries, and the most widely accepted answer comes from a theory called JTB, which stands for Justified True Belief. The idea is straightforward: to truly know something, you need three things. You have to believe it. It has to be true. And you need a good reason for believing it, not just a gut feeling or a lucky guess.
Think of it like a jury. A verdict is not just about what the jury thinks happened. It has to be true, and it has to be supported by real evidence. Belief alone is not enough. Neither is truth without justification.
There are also different flavors of knowledge worth knowing about. There is knowledge through direct experience, like knowing what coffee tastes like. There is practical knowledge, like knowing how to ride a bike. And there is propositional knowledge, knowing that something is true, like knowing that 2+2=4. Most of what we call knowledge is some combination of all three.
Then there is the question of where knowledge even comes from. Rationalists would say reason. Descartes summed it up with his famous line: “I think, therefore I am.” If you can think, you can reason your way to truth. Empiricists push back and say no, knowledge comes from experience. You learn by observing, touching, tasting, living. Both camps have a point, which is probably why most of us land somewhere in the middle.
Now here is where it gets interesting.
A philosopher named Edmund Gettier came along in 1963 and quietly broke everything.
Imagine you are driving and you see a white fluffy animal on a hill in the distance. Based on the shape, the color, and every sheep you have ever seen, you conclude there is a sheep on that hill. You know it. Then you get closer and realize it is actually a dog. A white fluffy dog that looked exactly like a sheep from far away.
So did you know there was a sheep? You believed it. You had good reasons to believe it. But it was not true.
Gettier called this a problem, and it is a good one. Because it suggests that justified true belief might not be enough. You can check all three boxes and still be wrong. You can be completely confident in something that turns out to be false.
Here is another way to think about it. When you had your first child, you learned that a pregnancy takes nine months. That was your knowledge. Solid, justified, true. Now imagine science updated that understanding. Suddenly what you knew is no longer accurate. Does that mean you never really knew it?
This is what makes knowledge such a strange thing. It feels permanent. It feels like once you know something, you know it. But knowledge can expire. It can be wrong from the start without you realizing it. It can be justified and still miss the truth entirely.
So what is knowledge?
It is our best attempt at understanding reality. A combination of belief, truth, and justification that we use to make sense of the world around us. It is not perfect. It is not permanent. But it is the closest thing we have to solid ground.
The real question Gettier left us with is not just what knowledge is. It is whether we can ever truly be certain we have it.
I would love to know what you think. Drop a comment and let’s figure this out together.