Introduction
In philosophy, understanding what knowledge is has been a central concern for centuries. One well-known definition is “Justified True Belief” (JTB). According to this view, a person knows something if three conditions are met: the belief must be true, the person must believe it, and there must be justification for the belief. This essay explains each part of this definition and evaluates whether it truly explains what knowledge is.
The Three Parts of Justified True Belief
1. Belief
To have knowledge, one must believe the statement or fact. If someone doesn’t believe something, they can’t claim to know it. For example, if Ravi doesn’t believe that water boils at 100°C, we wouldn’t say he knows it, even if it’s true.
2. Truth
Just believing something doesn’t make it true. For a belief to be considered knowledge, it must actually be true. For instance, someone may believe that the moon is made of cheese, but that’s not true, so it’s not knowledge.
3. Justification
This means having good reasons or evidence for the belief. If you guess the answer to a question correctly without any reason, it’s not knowledge. But if you study and answer it correctly based on that study, it’s justified. Justification adds value and support to a belief.
Why Was This Definition Accepted?
For a long time, philosophers accepted the JTB definition because it seemed to cover all the important parts of knowing something. It combined belief, truth, and logical reasoning — three things that seemed essential for real knowledge. Plato, in his dialogues, hinted at this view, and it became a standard in Western philosophy.
Gettier’s Challenge
In 1963, philosopher Edmund Gettier presented some problems (called “Gettier cases”) that challenged the JTB definition. He showed situations where all three conditions were met, but it still didn’t feel like real knowledge.
Example:
Suppose Sita looks at a perfectly working clock that says it’s 3:00. She believes it is 3:00, and it is actually 3:00. So her belief is justified and true. But what if, unknown to her, the clock had stopped 24 hours earlier and coincidentally shows the correct time now? In that case, her belief is true and justified, but it’s just luck — not real knowledge.
Is JTB Still a Valid Definition?
Many philosophers still consider JTB a good starting point. They have tried to improve it by adding more conditions to avoid Gettier-type problems. Some say we need to ensure the justification is not based on any false belief. Others argue we should include the reliability of the method used to form the belief.
Arguments Supporting JTB
- It’s simple and easy to understand.
- It includes all three important elements: belief, truth, and reasons.
- It has helped frame discussions on knowledge for centuries.
Arguments Against JTB
- It cannot handle Gettier problems without additional rules.
- It may not explain how people gain knowledge in real-world situations like intuition or creativity.
Conclusion
The idea of knowledge as justified true belief is a strong and useful definition. It covers the essential elements of belief, truth, and reason. However, it is not perfect. Gettier problems show that just meeting these three conditions may not always mean we have true knowledge. Despite its limitations, JTB remains an important and helpful way to think about knowledge, especially for students trying to understand how we know what we know.