Here in Silicon Valley, I have taken part in hundreds of conversations trying to convince people to dive in and become entrepreneurs. All too often, innovators with good, safe, jobs are unwilling to put their family's access to health care at risk by walking away from company-backed medical insurance.

If you cannot fail, you cannot learn.

Zero invites imagination, but small numbers invite questions about whether large numbers will ever materialize.

Entrepreneurs can't forecast accurately, because they are trying something fundamentally new. So they will often be laughably behind plan - and on the brink of success.

A Start Up is an institution designed to thrive in the soil of extreme uncertainty

At IMVU, the cost of customer acquisition through our five-dollar-a-day AdWords campaign was less than twenty-five cents. Our revenue from those same customers was more than a dollar.

This is one of the most important lessons of the scientific method: if you cannot fail, you cannot learn.