I found this really fascinating:
All decisions involving uncertainty fall within two distinct categories-those with contingencies, and those without. The latter are distinctly more difficult to deal with.
Most decisions, and nearly all human interaction, can be incorporated into a contingencies model. For example, a President may start a war, a man may sell his business, or divorce his wife. Such an action will produce a reaction; the number of reactions is infinite but the number of probable reactions is manageably small. Before making a decision, an individual can predict various reactions, and he can assess his original, or primary-mode, decision more effectively.
But there is also a category which cannot be analyzed by contingencies. This category involves events and situations which are absolutely unpredictable, not merely disasters of all sorts, but those also including rare moments of discovery and insight, such as those which produced the laser, or penicillin. Because these moments are unpredictable, they cannot be planned for in any logical manner. The mathematics are wholly unsatisfactory