Although, I never really was able to reconcile Thiels' criticism of an 'indefinite' worldview. It appears to me if the factors that influence things are not only the unknowns but the are unknown unknowns (i.e. you don't even know what you would need to know that will determine the fate of the company/country/whatever). In that case, how could you be anything but uncertain and just try to structure your life to benefit from convexity or as Taleb coined, anti-fragility?