After telling the story of co-founding PayPal — where the team's goal was nothing less than replacing the U.S. dollar with a new digital currency — Thiel noted a clear pattern: the more experience someone had in banking, the more certain they were that the venture could never succeed. They were wrong. PayPal now moves more than $200 billion every year. The lesson Thiel drew was that while they failed at their grandest ambition, doing new things is far from impossible. Youth's ignorance of what 'can't be done' is actually its greatest asset.