Why at eight?

About this video

Theo is four, and he has learned the best question in the world. "We're going to the bakery at eight," says his sister Rosa. "Why at eight?" "Because it opens at eight." "Why?" "Because the sign on the door says so." "Why?" "Because the baker wrote it." "Why do you believe the baker?" Rosa stops.

In Knowledge Level 1 we said that knowledge needs good reasons. But a reason is itself a belief - "the sign says eight" - and it needs a good reason too, and that reason needs one. Each reason hangs from the one behind it, like links in a chain: the chain of reasons. Philosophers call this the problem of the regress, a word that means "going back".

About 2,000 years ago, a Greek thinker called Agrippa saw that the chain can go only three ways, and none looks good at first. It never ends: but then you would need infinitely many reasons before you could know anything, and nobody has them. It goes round in a circle: "I trust the sign because the baker is honest, and I know the baker is honest because the sign is right" - the belief ends up being its own reason. Or it stops somewhere: "this one needs no further reason". But why is stopping there allowed, and not one step earlier?

It is one of the oldest puzzles about knowledge. Philosophers have answered in two main ways: the chain stops at beliefs that need no further reason, or beliefs hold each other up together, like the answers in a crossword. Neither side has won. This video goes with the lesson A Reason for Every Reason? in Knowledge Level 2 on Knaph.

Transcript

1. 0:00Rosa says, we go to the bakery at eight. Theo asks, why?
2. 0:05It opens at eight. Why? The sign says so. Why? The baker wrote it.
3. 0:11Agrippa saw three ways it could go. One, it never ends.
4. 0:17Two, it goes round, and the belief ends up as its own reason.
5. 0:23Three, it stops somewhere. But why there, and not one step earlier?
6. 0:29Every reason is a belief that needs a reason too.