Do babies understand numbers, or are they a blank slate?  Is it a given that they will grow to understand numbers like we do, or do they need to be taught?  Is how we experience numbers different from how stone age people understood them?

These questions and more are examined in this Radiolab podcast from October 9, 2009.

The answers made me think deeper about what we know, how we know it, and if it’s real or a human invention.