The chicken and the farmer

About this video

A chicken lives on a farm. Every morning the farmer comes out and throws it some grain. After a hundred mornings the chicken is sure: when the farmer comes, food comes. Then one morning the farmer comes out and, instead of feeding it, catches it for the family's dinner. The chicken had a hundred good examples, and it was still wrong. Bertrand Russell told this story in 1912, and he wasn't really talking about chickens. He was talking about us.

Almost everything we expect, we expect because of the past. The Sun has risen every morning of your life, so you expect it tomorrow. Going from many past cases to a general rule or to the future is called induction, and we do it all day long.

Nearly 300 years ago David Hume asked what our reason is to believe that the future will be like the past. We can't know it by thinking alone: there is no contradiction in "the Sun won't rise tomorrow", the way there is in "a triangle has four sides". So it must come from experience - but saying "in the past, the future has always been like the past" is induction again. We would be using induction to prove that induction works, going round in a circle. This is the problem of induction, and there is still no answer everyone accepts.

Hume thought we can't stop expecting anyway: it is how our minds work. But two things make it safer. Expecting the future to be like the past works best when we know why something happens - the Sun rises because the Earth spins, while the chicken knew nothing about why it was fed. And the more varied our past cases, the better. This video goes with the Will the Sun Rise Tomorrow? lesson of Knowledge Level 2 on Knaph.

Transcript

1. 0:00A chicken is fed every morning. After a hundred mornings, it is sure.
2. 0:05Then one morning, the farmer comes for dinner.
3. 0:11We expect tomorrow because of the past. That is induction.
4. 0:17Hume asked why. Not by thinking, and from experience it goes in a circle.
5. 0:23We can't stop expecting. Knowing why it happens makes it safer.
6. 0:29Is the future like the past?