Edmund Gettier - Is Justified True Belief Knowledge?

You know how sometimes you're really sure about something, but it turns out to be wrong, like thinking your favorite toy is still in your backpack when it's actually at home.

Justified true belief is a way people used to think about knowledge. It means if you believe something, and your reason for believing it is good enough, and what you believe is actually true, then that’s knowledge. But Edmund Gettier showed that this idea doesn’t always work, like when you're sure about something, but the reason you're sure is a bit tricky.

Imagine you have a bag full of toys. You think your favorite toy, let's say it's a red ball, is in there. Your reasoning? You saw your friend put a red ball into the bag earlier. But actually, your friend put a blue ball in instead. However, the red ball was hiding under some other toys all along.

You believed the red ball was in the bag, and you were right (it was in there), but your reason wasn’t perfect, it was just lucky. That’s like Gettier's example, where justified true belief happens, but it’s not always knowledge.

So sometimes being sure about something doesn't mean you know it, it might be more like a happy accident!