Should we or should we not set big, hairy, audacious goals where success is far from certain (at least without the benefit of hindsight)?

I for one am grateful for the existence of people who set big goals. My country (the USA) would not exist otherwise. Nor would my city, my family, our computers, the Internet, my breakfast, this Thanksgiving holiday, or the various freedoms I enjoy today. A number of people close to me would be dead if not for the existence and drive of