The Turtle system is classic targeting of an opportunity. Take what is given and ride the bucking bronco of a trend up or down. This is the thinking needed to find a target of opportunity. Trend Follower View of World Unstable world. World is uncertain and dynamic.
Market players form rational beliefs but make mistakes.
Fundamental changes are often unanticipated. Non-Trend Follower View of World Stable world. World is knowable and static. Market players generally form rational expectations. Markets adjust quickly to new information.