Think about your mistakes. Often they are not when we are in the swing of things and solving problems as we go. Humans are pretty good at that. I recall working out how to get a heavy twenty five foot canoe down a thirty foot rockface and into fast moving water. It was a fun problem to solve- and we managed it. But what if this had been the wrong river? All the solving in the world would have just got us deeper into trouble. We assume wrongly that screw ups are made as we go along but actually there are some highly inefficient workers who always manage to get a good job done. Because the real problems and disasters are all in the assumptions we make at the beginning. A truly colossal fuck-up is always there before a single move has been made. Just as a battle is almost always won or lost before any engagement, so too, a project is doomed from the outset or blessed by virtue of the assumptions we make. Before setting off on a big project ask yourself what are the assumptions we are making here. And then, as Idries Shah suggests, ask yourself what are the assumptions behind these assumptions.