That’s not to say that all uncertainties are created equal. There are many things we don’t know with 100 percent certainty about the future, but we do know enough to make an educated guess. Demographic changes, for example,are largely predetermined by long-term trends.their degree of uncertainty is very low. Not so with many other trends (e.g. new technologies)which may come screaming out of the blue, taking the market and the world by complete surprise.