That hurts

About this video

Amir bumps his knee on the table. "Ouch," he says, "that hurts." His friend Lina asks, "How do you know it hurts?" What could he say? "I can feel it" isn't really a reason for the belief - it is just the belief again. And yet he doesn't seem to need a reason.

The chain of reasons could go on forever, go round in a circle, or stop somewhere. This answer says it stops. Some beliefs you don't believe because of another belief, but because of what you feel or seem to see right now: "I am in pain", "I am thinking", "there seems to be something red in front of me". Philosophers call them basic beliefs: beliefs that need no further reason.

Think of knowledge as a house standing on a foundation. "I see a red, round shape" is a foundation stone; "there is an apple on the table" rests on it; "someone bought apples today" rests on that. The bottom beliefs hold themselves up. This view is called foundationalism, and Descartes held it: he looked for one belief so certain that everything could be built on it, and found "I am thinking".

The idea has two hard questions. Are the stones really safe? "I see something red" can be wrong in strange light, and even pain can be confused with pressure or an itch. And are there enough of them? From "I see red" and "I feel pain" you can't build very much - how would you get to "Cairo is in Egypt" or "the Earth is round"? Friends of foundations reply that the stones only need to be believable without further reasons. The argument continues. This video goes with the Where Reasons Stop lesson of Knowledge Level 2 on Knaph.

Transcript

1. 0:00Amir bumps his knee. That hurts! Lina asks, how do you know?
2. 0:05I am in pain. I see something red. Beliefs that need no further reason.
3. 0:11Everything else is built on them, like a house on its foundation.
4. 0:17First hard question. Are the stones safe? Red can fool you in strange light.
5. 0:23Second. Are there enough? From I see red, how do you get to Cairo?
6. 0:29Maybe the chain of reasons stops at what you feel right now.