Two teams of hikers, each crossing a glacier, approached a crevasse. One team saw the crevasse in time and stopped. The other team did not see the deep hole in the ice until the leader had fallen into it, at which time it became rather dramatically perceptible. Different perceptions obviously result in different actions. Perception, in this instance, changed action but perception did not change reality: the crevasse was really there whether noticed or not. Human systems, however, can be more complicated because perception can actually change the reality, at least to some degree.

Consider a thought experiment in the bulk wine market…